Macropis Cuckoo Bee (Epeoloides pilosulus): COSEWIC assessment and status report 2025

Official title: COSEWIC assessment and status report on the Macropis Cuckoo Bee (Epeoloides pilosulus) in Canada

Data Deficient

2025

COSEWIC assessment summary

Assessment summary – May 2025

Common name: Macropis Cuckoo Bee

Scientific name: Epeoloides pilosulus

Status: Data Deficient

Reason for designation: This very rare cuckoo bee lays its eggs in other bee nests and requires a specialized combination of its host bee (Macropis nuda), and the host’s food plants (native oil-producing loosestrifes). Since the first status report, eight additional sites have been recorded, greatly expanding the species’ known Canadian distribution. Based on the new information on distribution, there is substantial unsurveyed potential habitat for the cuckoo, host bee, and the host bee’s food plants across Canada. It is no longer possible to make conclusions about the species’ extent of occurrence, population size, threats, or trends. Thus, there was a change in status from Endangered to Data Deficient.

Occurrence: Alberta, Saskatchewan, Manitoba, Ontario, Quebec, New Brunswick, Nova Scotia

Status history: Designated Endangered in May 2011. Species considered in May 2025 and placed in the Data Deficient category..

COSEWIC executive summary

Macropis Cuckoo Bee

Epeoloides pilosulus

Wildlife species description and significance

Macropis Cuckoo Bee, Epeoloides pilosulus (Cresson, 1878), is the only North American member of this genus, the other species being found in Europe. Epeoloides Giraud, 1863 is the only genus in the tribe Epeoloidini (Apidae, Nomadinae), a unique lineage of bees containing only these two species that are nest parasites (henceforth referred to as cuckoo bees) of bees of the genus Macropis Panzer, 1809 (Melittidae), all of which are Lysimachia spp. plant oil-collecting obligates. Female cuckoo bees sneak into the nests of their host(s) and lay eggs on the food provision collected by the female host bee. The host’s egg and/or larva is killed by the cuckoo, which then consumes the food provision.

Aboriginal (Indigenous) knowledge

All species are significant and are interconnected and interrelated. There is no species-specific aboriginal (Indigenous) traditional knowledge in the report.

Distribution

Globally, Macropis Cuckoo Bee ranges in North America from Alberta east through Saskatchewan, Manitoba, Ontario, Quebec, New Brunswick, and Nova Scotia in Canada, and south throughout much of the eastern and central United States. There is a scattering of more recent iNaturalist records, including Massachusetts, New Hampshire, and New York.

Macropis Cuckoo Bee is arguably one of the rarest bees in North America. The first specimen in Canada was collected from Quebec in the late 1880’s and only 25 specimens have ever been collected or observed in Canada. In the past 50 years, it has been collected in Canada from Ontario (1978), Nova Scotia (2002), Alberta (2010), Saskatchewan (2013), Manitoba (2019, 2020, 2022) and New Brunswick (2023). There are seventeen subpopulations recorded in Canada: eight extant and nine historical. In the last ten years (2015-2024), only eight specimens have been collected or observed despite increased bee collecting throughout much of southern Canada.

Habitat

Macropis Cuckoo Bee is found in habitats supporting both their host bee (Macropis nuda) and the host’s food plants (that is, oil producing Lysimachia species – Fringed Loosestrife [L. ciliata] and Swamp Candles [L. terrestris] are likely the most important). Host bee food plants grow in ephemeral wet habitats, though both host bee and the host’s food plants have been recorded from drier, albeit shadier habitats. Both Macropis Cuckoo Bee and the host bee also use dogbane (Apocynum spp.) and potentially other milkweeds (Asclepias spp.) as nectar plants, and their presence with host bee food plants may be a good indicator of suitable habitat for both bee species. Host bee nest sites are typically within or adjacent to patches of the host’s food plant, in sandy soil with sun exposure and vegetative undergrowth.

Biology

Macropis Cuckoo Bee has an annual life cycle; adults emerge in June and July. Peak activity of the cuckoo coincides with peak nesting activity of the host bee which occurs in July and corresponds with flowering of the host bee’s food plants. Males and females overwinter as mature larvae (that is, pre-pupae) within host bee nests, and re-commence development as heat units are accumulated in the following spring. Females then search out host nests using scent and lay their egg within the host nest. Unlike most cuckoo bees, Epeoloides spp. females stay in host nests for a long time (one hour or more), mainly to construct a cell closure after laying their egg. Epeoloides spp. eggs hatch into larvae and begin consuming food provisions intended for the host’s offspring. The cuckoo larvae pass through 4 or 5 instars before entering diapause (that is, overwintering).

Population sizes and trends

Sampling effort, collecting methods, and available data are insufficient to assess the range wide population size and trends for Macropis Cuckoo Bee. Most sampling efforts have not been systematic and have only detected the presence of the cuckoo bee in a few areas, while other efforts have documented its host and/or the host’s food plant(s). It is unknown if Macropis Cuckoo Bee subpopulations are severely fragmented, although poor dispersal ability of both cuckoo and host bee, combined with low abundance and presumed isolated extant subpopulations, render it probable.

Threats

The main threats to Macropis Cuckoo Bee are inferred; threats that could impact the abundance and/or distribution of the host bee’s food plants, including habitat loss, degradation, fragmentation, and conversion. These threats primarily fall under other ecosystem modifications. For example, the continued spread of non-native and invasive plants such as Purple Loosestrife (Lythrum salicaria; not related to the loosestrife host bee plants) and European Common Reed (Phragmites australis subsp. australis) in wet areas cause ecosystem modifications that degrade bee host’s food plant habitat. Other non-native plant species are also important competitors with the bee host’s food plant in drier habitats, including thistles (Cirsium spp.) and Leafy Spurge (Euphorbia esula).

Protection, status, and recovery activities

Macropis Cuckoo Bee was assessed as endangered by the Committee on the Status of Endangered Wildlife in Canada in 2011 and listed as such on Schedule 1 of the federal Species at Risk Act (SARA) in 2018. Critical habitat was not identified in the federal recovery strategy. Macropis Cuckoo Bee is globally and nationally assessed as Critically Imperilled (G1/N1 respectively).

Technical summary

Epeoloides pilosulus

Macropis Cuckoo Bee

Abeille-coucou de Macropis

Indigenous names: None

Range of occurrence in Canada: Alberta, Saskatchewan, Manitoba, Ontario, Quebec, New Brunswick, Nova Scotia

Demographic information

Generation time

1 year

Based on known life history and seasonal phenology (adults observed during June/July and no evidence of a second brood)

Is there an [observed, estimated, inferred, or projected] continuing decline in number of mature individuals?

Unknown

Insufficient information to determine continuing decline in mature individuals. In the last ten years (2015-2024), only eight specimens have been collected or observed despite increased bee sampling throughout much of southern Canada.

[Observed, estimated, or projected] percent of continuing decline in total number of mature individuals within 3 years [or 1 generation; whichever is longer up to a maximum of 100 years]

Unknown

Insufficient information to determine continuing decline in total number of mature individuals. In the last ten years (2015-2024), only eight specimens have been collected or observed despite increased bee search effort throughout much of southern Canada.

[Observed, estimated, or projected] percent of continuing decline in total number of mature individuals within 5 years [or 2 generations; whichever is longer up to a maximum of 100 years]

Unknown

Insufficient information to determine continuing decline in total number of mature individuals. In the last ten years (2015 to 2024), only eight specimens have been collected or observed despite increased bee search effort throughout much of southern Canada.

[Observed, estimated, inferred, or suspected] percent [reduction or increase] in total number of mature individuals over the last 10 years [or 3 generations; whichever is longer]

Unknown

Insufficient information to determine continuing decline in total number of mature individuals. In the last ten years (2015-2024), only eight specimens have been collected or observed despite increased bee search effort throughout much of southern Canada.

[Projected, inferred, or suspected] percent [reduction or increase] in total number of mature individuals over the next [10 years, or 3 generations, up to a maximum of 100 years]

Unknown

Insufficient information to determine continuing decline in total number of mature individuals. In the last ten years (2015-2024), only eight specimens have been collected or observed despite increased bee search effort throughout much of southern Canada.

[Observed, estimated, inferred, projected, or suspected] percent [reduction or increase] in total number of mature individuals over any period of 10 years [or 3 generations; whichever is longer, up to a maximum of 100 years], including both the past and future (up to a maximum of 100 years in future)

Unknown

Insufficient information to determine continuing decline in total number of mature individuals. In the last ten years (2015 to 2024), only eight specimens have been collected or observed despite increased bee search effort throughout much of southern Canada.

Are the causes of the decline clearly reversible?

No

At ephemeral wetland habitats, causes of decline include habitat degradation from invasive non-native plant species and prolonged droughts (climate change). However, there is insufficient information to determine whether there is decline across the cuckoo bee’s entire Canadian range.

Are the causes of the decline clearly understood?

Partially

At ephemeral wetland habitats, causes of decline include habitat degradation from invasive non-native plant species and prolonged droughts (climate change). However, there is insufficient information to determine whether there is decline across the entire Canadian range.

Are the causes of the decline clearly ceased?

No

At some ephemeral wetland habitats, causes of decline include habitat degradation from invasive non-native plant species and prolonged droughts (climate change). The causes of decline in some of these habitats may have ceased due to mitigative or other measures. However, there is insufficient information to determine whether the causes of decline have ceased across the entire Canadian range.

Are there extreme fluctuations in number of mature individuals?

Unknown

Insufficient information to determine extreme fluctuations in mature individuals.

Extent and occupancy information

Estimated extent of occurrence (EOO)

1,497,441 km²

Calculated based on minimum convex polygon around extant subpopulations 2015-2024 = 1,497,441 km^2.

Index of area of occupancy (IAO), reported as 2 x 2 km grid value

36 km²

Extant subpopulations 2005 to 2024 = 36 km².

Is the population “severely fragmented”, that is, is >50% of individuals or >50% of the total area “occupied” (as a proxy for number of individuals) in habitat patches that are both (a) smaller than required to support a viable subpopulation, and (b) separated from other habitat patches by a distance larger than the species can be expected to disperse?

1. Unknown
2. Unknown

1. The size of the habitat patches necessary to sustain a subpopulation is unquantified; both cuckoo and host bees occur in low abundance, and it is not possible to determine spatial habitat needs
2. The cuckoo and host bee presumably have low dispersal ability. The foraging distance of the host bee is 120 to 600 m from nest

Number of “locations” (use plausible range to reflect uncertainty if appropriate)

> 8

If all extant (8) and historical (9) subpopulations are considered a separate location (total 17) based on threats to habitat (for example, cumulative habitat loss, fragmentation and ecosystem change from invasive non-native species compounded by prolonged droughts from climate change). Some sites are old (> 50 years) and it is unknown if habitat remains. There are likely additional undocumented subpopulations.

Is there an [observed, inferred, or projected] continuing decline in extent of occurrence?

Unknown

Over the past ten years (2015 to 2024), there is an observed decline in EOO despite extensive bee sampling. However, the habitat needs of the bee remain unknown, and it is unknown if the cuckoo remains at historical sites and unsurveyed habitat.

Is there an [observed, inferred, or projected] continuing decline in area of occupancy?

Unknown

Over the past ten years (2015 to 2024), there is an observed decline in IAO despite extensive bee sampling. However, the habitat needs of the bee remain unknown, and it is unknown if the cuckoo remains at historical sites and unsurveyed habitat.

Is there an [observed, inferred, or projected] continuing decline in number of subpopulations?

Unknown

Over the past ten years (2015 to 2024), there is an observed decline in number of subpopulations despite extensive bee sampling. However, the habitat needs of the bee remain unknown, and it is unknown if the cuckoo remains at historical sites.

Is there an [observed, inferred, or projected] continuing decline in number of “locations”?

Unknown

Some records are old (> 50 years) and determining threats at these sites is not possible.

Is there an [observed, inferred, or projected] continuing decline in [area, extent and/or quality] of habitat?

Yes

Observed, inferred and projected decline in area/quality of wetland habitat, based on spread of non-native plants. However, the host bee host’s food plants also occur in drier sites, and there is extensive potential unsurveyed habitat.

Are there extreme fluctuations in number of subpopulations?

Unknown

Insufficient data

Are there extreme fluctuations in number of “locations”?

Unknown

Insufficient data

Are there extreme fluctuations in extent of occurrence?

Unknown

Insufficient data

Are there extreme fluctuations in index of area of occupancy?

Unknown

Insufficient data

Number of mature individuals (by subpopulation)

All subpopulations

Unknown

Insufficient data

Total

Unknown

Insufficient data

Quantitative analysis

Is the probability of extinction in the wild at least 20% within 20 years [or 5 generations], or 10% within 100 years?

Unknown

Analysis not conducted

Threats

Was a threats calculator completed for this species?

Yes

Overall assigned threat impact: Medium-Low

Threats conference call completed September 19, 2023 (see Appendix 1). The overall threat impact is Medium-Low. Key threats were identified as:

2.1 Annual and perennial non-timber crops – Low impact

7.1 Fire and fire suppression – Unknown

7.3 Other ecosystem modifications – Low impact

9.3 Agricultural and forestry effluents – Low impact

9.5 Air-borne pollutants – Unknown

11.1 Habitat shifting and alteration – Unknown

11.2 Droughts – Low impact

What limiting factors are relevant?

• Small subpopulation size
• Limited dispersal ability
• Natural parasitic enemies
• Host bee and host bee’s plant specificity
• Nest site specificity
• Vulnerability to weather patterns

Rescue effect (from outside Canada)

Status of outside population(s) most likely to provide immigrants to Canada.

Unknown

The national conservation status rank in the United States is NNR (national status not ranked) and state status ranks are Connecticut: S1, Maryland: SH, Massachusetts: S2, New Jersey: SNR, New York: S1, North Carolina: SNR, Pennsylvania: SNR, Virginia: SH, Wisconsin: S1 (NatureServe 2025).

Is immigration known or possible?

Unknown

Not likely possible; the bee has limited dispersal ability.

Would immigrants be adapted to survive in Canada?

Yes

There is no information that suggests subpopulations in the United States have different life history requirements.

Is there sufficient habitat for immigrants in Canada?

Yes

Both the host bee and host’s food plants are widespread.

Are conditions deteriorating in Canada?

Unknown

Both the host bee and host’s food plants are widespread in Canada, though in southern parts of its range. One recent study indicates that Canada may soon be more important for the host and host’s food plants in response to climate change, suggesting a northward shift in distribution.

Are conditions for the source (that is, outside) population deteriorating?

Unknown

Both the host bee and host’s food plants are widespread, and threats are unconfirmed in some parts of its potential range.

Is the Canadian population considered to be a sink?

Unknown

Both the host bee and host’s food plants are widespread and threats are unconfirmed in some parts of its potential range.

Is rescue from outside Canada likely, such that it could lead to a change in status?

No

The cuckoo and host bee presumably have low dispersal ability. The foraging distance of the host bee is 120 to 600 m from nest.

Wildlife species with sensitive occurrence data (general caution for consideration)

Could release of certain occurrence data result in increased harm to the Wildlife Species or its habitat?

No

The data are not considered sensitive.

Status and reasons for designation

Status: Data Deficient

Alpha-numeric codes: None

Reason for change in status: Vii

Reasons for designation: This very rare cuckoo bee lays its eggs in other bee nests and requires a specialized combination of its host bee (Macropis nuda), and the host’s food plants (native oil-producing loosestrifes). Since the first status report, eight additional sites have been recorded, greatly expanding the species’ known Canadian distribution. Based on the new information on distribution, there is substantial unsurveyed potential habitat for the cuckoo, host bee, and the host bee’s food plants across Canada. It is no longer possible to make conclusions about the species’ extent of occurrence, population size, threats, or trends. Thus, there was a change in status from Endangered to Data Deficient.

Applicability of criteria

A: Decline in total number of mature individuals

Not applicable. Insufficient data to reliably infer, project, or suspect population trends.

B: Small range and decline or fluctuation

Not applicable. The species meets B2 with an Index of Area of Occupancy of 36 km² (2015-2024) and (iii) there is an inferred decline in the area, extent, and/or quality of habitat. However, the species likely exists at more than 10 locations (based on unsurveyed potential habitat) and it is unknown if the species meets severe fragmentation or experiences extreme fluctuations.

C: Small and declining number of mature individuals

Not applicable. Insufficient data to determine the number of mature individuals and/or continuing decline.

D: Very small or restricted population

Not applicable. The number of mature individuals and vulnerability to rapid and substantial population decline are unknown.

E: Quantitative analysis

Not applicable. Analysis not conducted.

Data Deficient: the status report has fully investigated all best available information, yet the information is insufficient to satisfy any criteria or assign any status. The records of occurrence are too infrequent and widespread to make any conclusions about the full Canadian extent of occurrence, population size, threats, or trends; surveys to verify occurrences, when undertaken, have not been sufficiently intensive or extensive to ensure the reliability of the conclusions drawn from the data gathered.

Preface

Macropis Cuckoo Bee (Epeoloides pilosulus) was assessed by COSEWIC in 2011 as Endangered and listed on Schedule 1 of the federal Species At Risk Act (SARA) in 2018. The bee is a cleptoparasite, requiring a host bee to complete its life cycle. The host bee also has specific host plants. At the time of the first status report, the cuckoo bee was known from six sites across five provinces (1888-2002), with a seventy-year gap between records. Since the first status report, ten additional specimens of Macropis Cuckoo Bee have been recorded from eight additional sites, bringing the total recorded subpopulations to seventeen (eight extant and nine historical, including one record from 1978 in Ontario that was in a drawer of unidentified museum specimens).

Much of the natural history of Macropis Cuckoo Bee remains unknown, although the European species (that is, E. coecutiens) has been studied in more detail. There are large areas of Canada that remain unsurveyed for bees, including the ranges of both Macropis Cuckoo Bee and its bee host. The host bee and host’s food plants are widespread throughout much of Canada, suggesting there are large expanses of potential habitat. Macropis Cuckoo Bee is considered rare throughout its Canadian range, although there is insufficient information to conclude threats, population or habitat trends across its entire geographic range.

COSEWIC history

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list. On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.

COSEWIC mandate

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species for the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens.

COSEWIC membership

COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal entities (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biodiversity Information Partnership, chaired by the Canadian Museum of Nature), three non-government science members and the co-chairs of the species specialist subcommittees and the Aboriginal Traditional Knowledge subcommittee. The Committee meets to consider status reports on candidate species.

Definitions

(2025)

Wildlife species

A species, subspecies, variety, or geographically or genetically distinct population of animal, plant or other organism, other than a bacterium or virus, that is wild by nature and is either native to Canada or has extended its range into Canada without human intervention and has been present in Canada for at least 50 years

Extinct (X)

A wildlife species that no longer exists

Extirpated (XT)

A wildlife species no longer existing in the wild in Canada, but occurring elsewhere

Endangered (E)

A wildlife species facing imminent extirpation or extinction

Threatened (T)

A wildlife species likely to become endangered if limiting factors are not reversed

Special concern (SC)*

A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats

Not at risk (NAR)**

A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances

Data deficient (DD)***

A category that applies when the available information is insufficient (a) to resolve a species’ eligibility for assessment or (b) to permit an assessment of the species’ risk of extinction

*

Formerly described as “Vulnerable” from 1990 to 1999, or “Rare” prior to 1990.

**

Formerly described as “Not In Any Category”, or “No Designation Required”

***

Formerly described as “Indeterminate” from 1994 to 1999 or “ISIBD” (insufficient scientific information on which to base a designation) prior to 1994. Definition of the (DD) category revised in 2006.

Wildlife species description and significance

Name and classification

Current classification

Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Hymenoptera Linnaeus, 1758

Suborder: Apocrita Gerstaecker, 1867

Superfamily: Apoidea Latreille, 1802

Family: Apidae Latreille, 1802

Subfamily: Nomadinae Latreille, 1802

Tribe: Epeoloidini Linsley and Michener, 1939

Genus: Epeoloides Giraud, 1863

Species: Epeoloides pilosulus (Cresson, 1878)

Subspecies in Canada: There are no described subspecies.

Taxonomic changes since the previous (COSEWIC 2011) status report

At the time of the last report, the genus Epeoloides was considered a disjunct member of the otherwise Neotropical bee tribe Osirini (Apinae) following the classification of Roig-Alsina (1989) and Michener (2007). More recent phylogenetic analysis (that is, Straka and Bogusch 2007; Cardinal et al. 2010; Sless et al. 2021) have recognized its evolutionary significance and uniqueness, returning it to its status as a monotypic genus within the tribe Epeoloidini, a taxon originally proposed by Linsley and Michener (1939). Since Michener (2007), many of the cuckoo bee lineages placed in the subfamily Apinae (including Epeoloidini) have been moved to subfamily Nomadinae. Nomadinae consists entirely of cuckoo bee lineages (Sless et al. 2021; Martins et al. 2025).

Common names

English: Macropis Cuckoo Bee. “Macropis” refers to the genus name of the melittid bees which are the hosts of Epeoloides.

French: abeille-coucou de Macropis.

Indigenous: None

Synonyms and notes

Macropis Cuckoo Bee (Epeoloides pilosulus) was first described as Nomada pilosula from specimens collected in New York in 1878. The species was clearly recognized by Cresson as a cuckoo, even from the single male specimen he examined (Cresson 1878). Synonyms are Nomia compacta Provancher 1888, Viereckella ceanothina Cockerell, 1907 (in Swenk 2007), and V. obscura Swenk, 1907.

Ducke (1909) described Epeoloides nearcticus in 1909, a species he felt was congeneric with the European (then monotypic) genus Epeoloides; the type species is Epeoloides coecutiens (Fabricius, 1775; originally described by Fabricius (1775) in the genus Apis Linnaeus, 1758); thus, he was the first to assign a North American species to the genus Epeoloides (see Krombein et al. 1979). Mitchell (1962) and Krombein et al. (1979) subsequently placed E. nearcticus and the other proposed names into synonymy with Epeoloides pilosulus (Cresson), excluding Epeoloides obscura (Swenk), which was treated as a valid species by Krombein et al. (1979) and Roig-Alsina (1989). However, Michener (2000, 2007) and Sheffield et al. (2004) concluded E. obscura was also synonymous with E. pilosulus. Thus, Epeoloides pilosulus is the only species of the cuckoo tribe Epeoloidini present in the United States and Canada, and one of only two species of the genus worldwide (Michener 2007). The other species ranges in Europe and is E. coecutiens.

Description of wildlife species

Macropis Cuckoo Bee is a nomadine (Nomadinae) bee species, the only member of the genus in the New World and the only member of the tribe Epeoloidini in the Americas. This distinct species and can be easily identified using keys in Mitchell (1962; eastern North America), Stephen et al. (1969; western North America); Michener et al. (1994; North and Central America), Michener (2000, 2007; global) and Packer et al. (2007; eastern Canada).

Macropis Cuckoo Bee is moderate-sized (body length 7.5-10 mm) with smooth, black to dark brown, shining integument (Figure 1). The species possesses apical tergal bands of erect, densely plumose, white hairs (Cresson 1878) on their abdomen, which are lacking in other Nomadinae in Canada. On the wing margins, the second submarginal cell is much smaller than the first or third (see Sheffield et al. 2004) and the apex of the marginal cell is separated from the wing margin (illustrated in Michener et al. 1994; Sheffield et al. 2004).

Figure 1. Female (left) and male (right) Macropis Cuckoo Bee (Epeoloides pilosulus). Photos by Cory S. Sheffield.

Male Macropis Cuckoo Bees have large eyes which are strongly convergent above, and a uniquely shaped pygidial plate on the 7^th abdominal tergum (Linsley and Michener 1939; see Sheffield et al. 2004). Macropis Cuckoo Bee females do not collect pollen and lack scopae (specialized pollen-collecting and carrying hairs). Unlike most nomadine females, Epeoloides spp. females lack a well-defined pseudopygidial area on the 5^th metasomal tergum. Linsley and Michener (1939), Mitchell (1962), and Sheffield et al. (2004) provide illustrations of various structures, and the latter also provided a habitus drawing.

Macropis Cuckoo Bee adults differ from similar cuckoo bees by the short but densely plumose bands of erect pubescence on the abdomen (Cresson 1878; Linsley and Michener 1939; Mitchell 1962) and the absence of the red and/or yellow integument markings characteristic of the common genus Nomada. The lack of bands and/or presence of dense patches of short, appressed hair (which superficially resemble integument markings) are typical of the epeoline genera Epeolus and Triepeolus. The melectine bees of the genera Brachymelecta and Melecta are typically larger than Macropis Cuckoo Bee and do not have bands on the abdomen, although appressed patches of pale hair may be present. The melectine bee Zacosmia maculata is comparably sized yet has dense patches of pale and brownish pubescence.

Immature stages of Macropis Cuckoo Bee have not been observed, though those of the European species have been described (see Straka and Bogusch 2007) and are assumed to be similar.

Most species have a unique Barcode Index Number (BIN); the DNA barcoding process enables specimens to be differentiated based on their BIN via comparison to the online barcode library (for further information on barcoding methods see Ratnasingham and Hebert 2007, 2013; BOLD Systems 2025). Macropis Cuckoo Bee specimens from Canada have been barcoded (Sheffield et al. 2017), in the Barcode of Life Data System (BOLD) and the identification of specimens is possible by comparing DNA barcode sequences of unidentified species to those referenced in BOLD.

Macropis Cuckoo Bee is dependent on the host bee Macropis nuda (Figure 2) to complete its life cycle. This host bee is also dependent on specific host food plants to complete its life cycle. In Canada, these host food plants are Lysimachia terrestris and Lysimachia ciliata (Figure 3). Information on the host bee and host food plants is inserted at various places throughout this report.

Figure 2. Female Macropis nuda (host bee), foraging on Lysimachia terrestris (host food plant) in Middleton, Nova Scotia, and on one of its preferred nectar plants, Apocynum cannabinum in Greenwater Lake Provincial Park, Saskatchewan. The latter is also used as a nectar plant by Macropis Cuckoo Bee. Photos by Cory S. Sheffield.

Figure 3. Examples of habitats where native Canadian Lysimachia spp. can be found. Small populations of Lysimachia terrestris in roadside ditches in A) Kings Co., and B) Yarmouth Co., Nova Scotia; C) Lysimachia ciliata growing next to a river in Guelph, Ontario; D) a large stand of Lysimachia terrestris at the edge of a lowbush blueberry field in Hants Co., Nova Scotia. Photos by Cory S. Sheffield.

Designatable units

Macropis Cuckoo Bee is being assessed as one designatable unit. There is no information on discreteness or evolutionary significance among subpopulations in Canada, and no differences among the DNA barcode sequences. There are no described subspecies. The species occurs within the Prairies, Boreal Plains, Boreal Shield, Mixedwood Plains, Atlantic Highlands, and Atlantic Maritime terrestrial ecozones of Canada (Canadian Council of Ecological Areas 2014).

Special significance

Macropis Cuckoo Bee is a unique member of the global bee fauna. Epeoloides has a disjunct distribution between Old and New World, E. pilosulus being one of two species in the genus globally and the only member of its genus in North America. Macropis (and all members of the Nomadinae) is the only genus in the tribe Epeoloidini which consists entirely of cuckoos. All known host taxa for Epeoloides spp. are floral oil-collecting specialists of the melittid genus Macropis. Macropis Cuckoo Bee and its close relationship with its host and host food plant provide an interesting example of how many species depend upon each other in complex ways.

Aboriginal (Indigenous) knowledge

Aboriginal Traditional Knowledge (ATK) is relationship-based. It involves information on ecological relationships between humans and their environment, including characteristics of species, habitats, and locations. Laws and protocols for human relationships with the environment are passed on through teachings and stories, and Indigenous languages, and can be based on long-term observations. Place names provide information about harvesting areas, ecological processes, spiritual significance, or the products of harvest. ATK can identify life history characteristics of a species or distinct differences between similar species.

Cultural significance to Indigenous peoples

There is no species-specific ATK in the report. However, Macropis Cuckoo Bee, its Macropis spp. hosts, and the oil-producing host food plants of the genus Lysimachia are important to Indigenous Peoples who recognize the interrelationships of all species within the ecosystem.

Distribution

Global range

Globally, Macropis Cuckoo Bee ranges within North America from Alberta to the Maritime provinces of Canada, south to Georgia, and west to Wisconsin, North Dakota and north to Montana (Wagner and Ascher 2008). The global range is patchy, and there are large expansive areas, especially in Canada, with no records. The global range is concurrent and smaller than the distribution of its host bee(s) and the host(s) food plants. The global range of Macropis Cuckoo Bee is approximately 2,592,155 km².

Canadian range

The Canadian range of Macropis Cuckoo Bee extends from Alberta (Elk Island National Park) through Saskatchewan (Wallwort, Wood Mountain area), Manitoba (Aweme, La Broquerie, Nourse, Sandilands Provincial Park, Florze, Lac du Bonnet), Ontario (One Sided [=Oneside] Lake, Milton), Quebec (Cap Rouge), Nova Scotia (Middleton) (Sheffield et al. 2004; Sheffield and Heron 2018; Gibbs et al. 2021, 2023) and New Brunswick (Arcadia) (Figure 4; Table 1). Approximately 60% of the species global range is in Canada.

Figure 4. The distribution of Macropis Cuckoo Bee (Epeoloides pilosulus), its host bee (Macropis nuda), and host bee host’s food plants (Lysimachia terrestris and Lysimachia ciliata) in Canada. Lysimachia terrestris records west of Saskatchewan are considered introduced and not considered part of the plant's native geographic range in Canada. Data from GBIF (2025). Map created by Ryan Collins (COSEWIC Secretariat, June 2025).

There are 17 known subpopulations^{Footnote 1} of Macropis Cuckoo Bee in Canada; eight extant^{Footnote 2} and nine historical^{Footnote 3} (Table 1). The distribution of Macropis Cuckoo Bee, the host bee, and the two Lysimachia spp. that serve as the host bee’s food plants are shown in Figure 4.

Macropis Cuckoo Bee is surveyed by both hand collection and by passive trapping methods. Hand collection involves the surveyor(s) carrying an aerial net, specifically targeting habitat patches with potential host bee plants, and capturing and euthanizing specimens caught using the net. Many bee species are not possible to identify on the wing, and most bee (genus) specific hand collection typically collects and euthanizes all bees encountered during a survey. Passive trapping for Macropis Cuckoo Bee involves bee bowls (also called pan traps) and malaise traps. Bee bowls involve placing a bowl (the colour of royal blue, white or bright yellow) filled with clear liquid (typically water or propylene glycol) in a patch of bee host food plants. Bees are drawn to the bowls and trapped by the liquid in the bowl. Bee bowls are typically left in place from a day to a week. Recent records of Macropis Cuckoo Bee on iNaturalist support that photography-based methods of documenting bee species may also be useful for documenting its presence, and in recognizing suitable habitat through the presence of host bee and host bee food plant subpopulations.

In total, ten specimens of Macropis Cuckoo Bee have been documented in Canada since 2005 (Table 1). There continues to be extensive bee sampling in southern Canada since the first Macropis Cuckoo Bee COSEWIC (2011) assessment (for example, Rubens 2019; Vickruck et al. 2019; Audet et al. 2021; Nelson et al. 2021; Gerner and Sargent 2022; Sharkey 2022; Gibbs et al. 2023). However, available online data supports the rarity of Macropis Cuckoo Bee. For example, specimens from Canada on the Global Biodiversity Information Facility (GBIF 2025a-f) total 455,474 records, and only 49 of are Macropis Cuckoo Bee (unfortunately, some of the occurrences of Macropis Cuckoo Bee in GBIF appear more than once). Between 2012 and 2024, 314,550 bee specimens have been documented from Canada on GBIF, yet only six of these are Macropis Cuckoo Bee (a corrected value due to the data duplication; the total numbers also represent and over-estimate due to duplicate records and include “Research Grade” data from iNaturalist). On iNaturalist there are 300,286 observations of bees from Canada (as of February 2025) represent 467 “species,” yet only one record of Macropis Cuckoo Bee (from New Brunswick) has been observed.

A summary of search efforts prior to 2011 is provided in the first COSEWIC (2011) status report, and one additional historical record from Ontario (1978) was found in unsorted museum specimens (Table 1).

Population structure

Macropis Cuckoo Bee records reveal a wide and patchy geographic distribution in Canada, although this is likely due to little sampling effort throughout most of its potential range. Genetic analysis of the mitochondrial gene COI (that is, the DNA barcode) from various specimens (for example, Sheffield et al. 2009; Sheffield et al. 2017 and specimens from Alberta [Sheffield and Heron 2018]) do not show any sequence variation across the species geographic range.

Extent of occurrence and area of occupancy

The extent of occurrence (EOO) is calculated using a minimum convex polygon that encompasses all known Canadian records of Macropis Cuckoo Bee. The index of area of occupancy (IAO) is calculated using a 2 x 2 km grid drawn over known records of Macropis Cuckoo Bee.

Current EOO includes extant records (2005 to 2024) and is estimated at 1,497,441 km². (Table 1; Figure 4).

Current IAO includes extant records (2005 to 2024) and is 36 km² (Table 1; Figure 4).

Much of the potential range of Macropis Cuckoo Bee (and its host) have not been surveyed in Canada (Figure 4). Using records from GBIF (2025a-h) the approximate EOO and IAO are:

• Host bee Macropis nuda EOO = 2,239,375 km² and IAO = 296 km²
• Host bee plant Lysimachia terrestris EOO = 4,049,063 km² and IAO = 9,056 km²
• Host bee plant Lysimachia ciliata EOO = 3,740,834 km² and IAO = 10,376 km²
• Both Lysimachia terrestris and Lysimachia ciliata EOO = 5,335,665 km² and IAO = 18,588 km²

Fluctuations and trends in distribution

There is insufficient data for Macropis Cuckoo Bee from which to determine fluctuations and trends in the populations and distribution. Despite extensive surveys throughout the southern extent of the cuckoo’s geographic range (see above), recent records have been limited to Nova Scotia (2002), Alberta (2010), Saskatchewan (2013), Manitoba (2019, 2020, 2022) and New Brunswick (2023). It is suspected that this species continues to occur in intact historical sites, and sites that are not easily accessible.

In the United States the range of the host bee and its main floral host, L. ciliata, are predicted to undergo habitat loss due to global warming (Buckner and Danforth 2022). This study projected a northward (that is, into Canada) range shift, which could result in a significant increase in the proportion of the host bee’s global range in Canada, and potential increase in the host abundance for Macropis Cuckoo Bee. However, this study overlooked other floral hosts used by the host bee in Canada, specifically L. terrestris (see Sheffield et al. 2004; COSEWIC 2011).

Biology and habitat use

Macropis Cuckoo Bee is a cuckoo in the nests of bees of the genus Macropis. This relationship (discussed in Sheffield et al. 2004; Sheffield and Heron 2018) is based on the well-known associations between the more abundant European species (E. coecutiens (Fabricius, 1775), and its two confirmed Macropis spp. hosts, M. europaea Warncke, 1973 and M. fulvipes (Fabricius, 1804) [Pekkarinen et al. 2003; Bogusch 2005; Celary 2004]); as well as historical (see Ascher 2005) and recent (Sheffield et al. 2004; Wagner and Ascher 2008; Sheffield and Heron 2018; Gibbs et al. 2021) co-occurrence of host and cuckoo in and near host food plant patches.

Macropis Cuckoo Bee has proved to be a challenging species to observe and study. A live specimen of Macropis Cuckoo Bee from New Brunswick was photographed and posted to iNaturalist in 2023 suggesting observational studies may be possible. However, most records have been through passive trapping, and habitat and natural history information inferred. The life history information summarized below is based on published accounts of Macropis Cuckoo Bee in North America, and that published for the European species, which is expected to be like the Macropis Cuckoo Bee.

Life cycle and reproduction

Globally, Macropis Cuckoo Bee can be inferred to parasitize all four North American Macropis spp. (see Table 2, and Michez and Patiny 2005). However, M. nuda (Figure 2) is the only confirmed species of Macropis in Canada and is the presumed host for Macropis Cuckoo Bee in Canada (Sheffield et al. 2004; Sheffield and Heron 2018; Gibbs et al. 2021).

^a The original type material of M. longilingua Provancher [= M. ciliata Patton] from Canada [Quebec, Cap Rouge] has been lost (see Snelling and Stage 1995; Sheffield and Perron 2014), so a neotype (a specimen of M. ciliata from New York) was designated by Snelling and Stage (1995) to fix the name to a specimen. However, Provancher’s (1888) brief description makes it difficult to confirm the synonymy of his species, and Snelling and Stage (1995) indicated that there was no certainty that it is even a Macropis, though Provancher described the hairs of the legs “avec poils blancs”, partially supporting the distinction between it and M. nuda (see Mitchell 1960; Snelling and Stage 1995; though the differences in mid and hind leg colour are restricted to the basitarsi only), but not necessarily between it and M. patellata Patton. Michener (1938) thought that Provancher’s species, likely based on description, was a probable synonym of either M. ciliata or M. patellata (as did Snelling and Stage 1995), but without having Provancher’s type material, its presence in Canada (INHS has a specimen identified as M. ciliata from NB) needs to be confirmed. Gibbs et al. (2023) recently reported that the specimen from MB (at INHS) was a misidentified M. nuda (Provancher).

^b Snelling and Stage (1995) indicated that this species occurred in [eastern] Canada in the discussion of M. longilingua described by Provancher (see footnote 2). Though no specific Canadian localities were provided, and Canada is not indicated in the range listed for M. patellata later in that work (Snelling and Stage 1995), or by Mitchell (1960). However, its known proximity to eastern Canada (southern Ontario and Quebec) indicates that it likely could occur in Canada.

The known flight season of Macropis Cuckoo Bee is June and July (Mitchell 1962). Peak nesting activity occurs in July and corresponds with peak host bee and bloom of its host’s food plant (Sheffield et al. 2004; Wagner and Ascher 2008; Sheffield and Heron 2018; Gibbs et al. 2021). The European congener flies from June to August (Pekkarinen et al. 2003).

The life cycle of Macropis Cuckoo Bee is probably like that of most summer flying bees (Stephen et al. 1969). Males and females overwinter as mature larvae (prepupae) within host bee nests and re-commence development as heat units are accumulated in the spring (see Sheffield [2008] for an account of development of another summer flying bee species). Adults emerge in late June through early July, mate, and feed on pollen and nectar. Females then search out host nests using scent and lay their egg within the host nest (Straka and Bogusch 2007; Dötterl 2008). Unlike most cuckoo bees, Epeoloides spp. females stay in host nests for a long time (one hour or more), mainly to construct a cell closure after laying their egg (Straka and Bogusch 2007). Other activities inside the nest are unknown (Straka and Bogusch 2007). Epeoloides spp. eggs hatch into larvae and begin consuming food provisions intended for the host’s offspring. The cuckoo larvae complete 4 or 5 instars before entering diapause (that is, overwintering).

Habitat requirements

Macropis Cuckoo Bee habitat requirements are grouped into three broad categories: 1) floral resources for Macropis Cuckoo Bee adults; 2) host nests for the cuckoo to parasitize; and 3) the habitat (including floral hosts) needed to sustain host bee subpopulations.

Macropis Cuckoo Bee adults visit a variety of plants for nectar (Mitchell [1962] listed four floral records), though observations and literature suggest that dogbanes and milkweeds are likely important nectar sources for both cuckoo and host bees (Figure 3).

Female host bees are entirely dependent on plants of the genus Lysimachia (Malyshev 1929; Popov 1958; Vogel 1976, 1986; Michez and Patiny 2005). Within the range of Macropis Cuckoo Bee, there are four species of host bee (Table 2) and 19 Lysimachia spp. (four of which are adventive) (Table 3). The Canadian distribution of L. ciliata and L. terrestris (Figure 4) is much more widespread than Macropis Cuckoo Bee or its host(s) (Popov 1958).

Lysimachia spp. normally grows in moist areas such as swamps, roadside ditches, and riparian zones (Figure 3), though some species also grow in drier areas out of direct sunlight. Dogbanes also grow in these habitats, and sites with both oil-producing Lysimachia spp. and dogbanes co-occurring are more likely to have the host present. Studies of M. nuda nest sites in eastern North America indicate a preference for sunny areas in sandy, well-drained soil, often amongst the floral hosts themselves (Rozen and Jacobson 1980; Cane et al. 1983). Macropis spp. bees are univoltine (that is, one generation per year) and are solitary, but often nest in small aggregations on sloping banks. Nests are typically shallow (ca 6.5 cm), with the entrances usually partially concealed by vegetation (Rozen and Jacobson 1980). Nesting tunnels are 3 to 3.5 mm in diameter and contain 2 to 4 linearly arranged brood cells (Rozen and Jacobson 1980) which are lined with oils obtained from the floral host (Cane et al. 1983). Malyshev (1929) provided a detailed account of the nesting biology of two European species of Macropis.

Movements, migration, and dispersal

Movements, migration and dispersal of Macropis Cuckoo Bee, the host bee and host bee plant are unstudied. The distances between healthy plant subpopulations are likely greater than the host and cleptoparasite can disperse. Solitary bees typically forage within 120 to 600 m of their nests, the distance increasing with body size (Gathmann and Tscharntke 2002). As such, large subpopulations of Lysimachia spp. (and dogbanes) are important for supporting subpopulations of M. nuda, and reduction in size or loss of plant subpopulations ultimately can lead to local extirpation. However, no studies have been conducted on foraging ranges or movement between floral host patches, although M. nuda females typically nest near their floral hosts (Pekkarinen et al. 2003). Macropis Cuckoo Bee does not migrate.

Interspecific interactions

Diet

Macropis Cuckoo Bee adults’ nectar on plants in the milkweed family, including dogbanes, milkweeds, and others. The females do not collect pollen provisions for their own offspring; they are reliant on the hosts’ provisions, which mainly includes Lysimachia spp. floral oils and pollen, and likely nectar of other plants (including dogbane) (Figure 3).

Predators and competitors

No specific predators have been recorded for Macropis Cuckoo Bee or host bees in North America. Likely predators include crab spiders and other general predators that specialize on insects as prey. There are no species-specific parasites, such as mites, dipterans, or pathogens, known for Macropis Cuckoo Bee or M. nuda.

Physiological, behavioural, and other adaptations

Macropis Cuckoo Bee is dependent on a single host bee genus (that is, M. nuda) which forages pollen and oil from flowers of a single plant genus. This specialization leaves cuckoo bee subpopulations highly susceptible to changes in the abundance of its host bee and its host’s food plant.

There have been no physiological or behavioural studies focused on Macropis Cuckoo Bee, although the species probably displays adaptations like other bees in temperate-zone climate (see Stephen et al. 1969 for a review). The only physiological studies of Epeoloides spp. examined electro-antennagraphic responses to floral constituents of Lysimachia spp. (Dötterl 2008). Like their host bees, Epeoloides spp. show similar responses to the odours of Lysimachia spp. pollen and oil; in M. nuda this probably helps find flowers (Dötterl and Schäffler 2007; Dötterl 2008). Dötterl (2008) suggests that these same odours are used by Epeoloides spp. to find the nests of their hosts. It is highly probable that Macropis Cuckoo Bee uses similar odour cues.

The temperate zone European species E. coecutiens only flies during warm (23-37°C) and sunny weather (Straka and Bogusch 2007). This species is limited to walking at temperatures below 18°C (Bogusch 2005). In hot weather, host bee females remain at nest entrances; an important nest defense from Epeoloides spp. attack (Straka and Bogusch 2007).

In North America, four additional Lysimachia spp. have been introduced and apparently are oil producers (Table 3). A few of these are widespread and able to grow in a variety of habitats, including dry areas within urban habitats and rural areas. One species, L. vulgaris, is considered the main pollen and oil plant of Macropis spp. in western Europe, though L. nummularia and L. punctata (from Asia) are also used (Pekkarinen et al. 2003). North American subpopulations of Macropis spp. may be able to use these plant species as suitable host food plants, however this is unstudied. Sheffield (unpublished observation) found that female host bees only foraged on native L. ciliata adjacent to a river in Guelph, Ontario (Figure 3C), despite a nearby (< 20 m) stand of an ornamental species which was much more abundant.

Recently, Buckner and Danforth (2022) reported that the main host bee of Macropis Cuckoo Bee (that is M. nuda) was entirely dependent on L. ciliata. However, this is not the case as Sheffield et al. (2004) collected M. nuda (and Macropis Cuckoo Bee) in sites containing only L. terrestris, the former foraging on it (Figure 3). Buckner and Danforth (2022) stressed that climate warming would likely move the distribution of M. nuda (host bee) and L. ciliata (host food plant) further northward. Their work suggests Macropis Cuckoo Bee may also be able to move with its host.

Limiting factors

Limiting factors are generally not human-induced and include intrinsic characteristics that make the species less likely to respond to conservation efforts. Limiting factors may become threats if they result in population decline. The main limiting factors for Macropis Cuckoo Bee are:

Small subpopulation size

The bee appears to occur as small or localized subpopulations, thus preventing genetic mixing between subpopulations, which could lead to inbreeding depression, increasing the chance of local extirpation.

Limited dispersal ability

The bee is likely not able to disperse long distances through unsuitable habitat. Subpopulation structure and spatially isolated habitats likely limit dispersal capabilities and subpopulation intermixing. Subpopulations of Lysimachia spp. (preferably those with dogbanes) are typically scattered and/or fragmented as they are often, though not exclusively, found in semi-moist habitats usually at distances much greater than the flight range of most medium-sized bees (Gathmann and Tscharntke 2002).

Natural parasitic enemies

Parasites are known to attack bees at all life stages, although no species-specific information is available for Macropis Cuckoo Bee, or its bee host.

Host bee and host’s food plant specificity

As Macropis spp. are dependent upon Lysimachia spp. for floral oils, their subpopulations are vulnerable to a reduction in these host food plants.

Nest site specificity

Loss or reduction of Macropis spp. nest aggregations is probably the most likely limiting factor for Macropis Cuckoo Bee in North America (Ascher 2005), although data supporting this are lacking, and other factors likely contribute to the uncommonness of bee host and cuckoo.

Vulnerability to weather patterns

The overall seasonal weather patterns affect the abundance and distribution of insects at all life stages. However, as the host’s food plants, and host bee nests (which also serves as the nest of Macropis Cuckoo Bee) are often in or near wet areas, if is possible that extreme flooding events could affect nesting habitat, especially if bees are actively nesting. Conversely, drought may also have an indirect negative impact on the bees by reducing the number of flowers available for nest provisioning.

Unrealized fecundity

Cuckoo bees have more ovarioles (potential eggs) per ovary than non-cuckoo taxa and produce more eggs during their life span than solitary bees (Alexander and Rozen 1987). In addition, a larger number of the eggs mature at any given time, allowing cuckoo bees to deposit eggs in rapid succession (Alexander and Rozen 1987). As such, female cuckoos can lay several eggs within a day while visiting the nests of several host bees. Typically, bees, whether the host taxa or cuckoo, lay a single egg on or near the food provision; one pollen “loaf” is used to produce one bee only. However, Epeoloides spp. may not reach its full fecundity due to intraspecific competition. According to Straka and Bogusch (2007), intraspecific competition between E. coecutiens larvae occurs within nests of the host, indicating that multiple female cuckoos may attack the same nest. Straka and Bogusch (2007) believe the brief first larval instar (followed by molting to the second instar which is the “killing” stage) is a selective pressure for intraspecific conflict (versus elimination of the host). Female Macropis spp. use effective nest guarding against Epeoloides spp. females (Straka and Bogusch 2007). Thus easily accessed nests may be in short supply, leading to multiple attacks of single nests, high levels of intraspecific competition and death of larval cuckoos, effectively reducing the fecundity of Epeoloides spp., an already rare bee.

Overall fecundity may also be reduced by the production of sterile males in place of females. In the very small, isolated subpopulations, like Macropis Cuckoo Bee, local extirpation may be due to intrinsic factors linked to the haplodiploid reproductive system of bees, that is, the production of sterile or inviable diploid males instead of fertile females as population size declines (Zayed and Packer 2005). As such, fewer egg-laying females would be produced within subpopulations, which exacerbates the other impacts of small subpopulation size. However, there are few studies of this phenomenon in the wild.

Population sizes and trends

Data sources, methodologies, and uncertainties

Sampling effort and methods have not been sufficient to assess the range wide population size and trends for Macropis Cuckoo Bee throughout much of Canada. Most historical and recent sampling efforts and collection of Macropis Cuckoo Bee have been incidental. A few recent efforts have focused on recording the distribution or presence of Macropis Cuckoo Bee, its host and/or the host’s food plant at a site (see Distribution/Canadian range).

Abundance

Most entomological collection events that target a specific area or habitat usually collect a minimum number of specimens that represent a series of individuals throughout that habitat type. No long series of Macropis Cuckoo Bee have been collected at any specific site and time, suggesting that it has likely always occurred in low abundance within its habitat. Historically in Canada, the longest series of Macropis Cuckoo Bee specimens collected during a site and year were four, collected in Wallwort, Saskatchewan over a ten-day period in 1942 (Table 1). Sheffield et al. (2004) collected two male specimens in Nova Scotia within a two-week period using yellow pan traps, although the subpopulation of the host bees was not large (that is, < 5 individuals were seen foraging at any time). Recently, seven specimens were collected at several sites within southern Manitoba over several years (see Table 1).

Although considered rare, the European species, E. coecutiens, is much more abundant than the North American species. Bogusch (2005) observed the behaviour of 45 individuals among nine localities in the Czech Republic, while Monsevièius (2004) collected almost 300 individuals with Moericke’s yellow-coloured traps in Èepkeliai Nature Reserve in South Lithuania between 1997 and 2001.

Fluctuations and trends

Macropis Cuckoo Bee population fluctuations and trends are unknown. There is no information to support a continuing decline^{Footnote 4} in number of mature individuals; evidence for continuing, projected, or suspected future decline; extinction risk based on quantitative analysis or long-term trends. There is no evidence of extreme fluctuations in the population. About 1/3 (that is, 8/25) of the known records of Macropis Cuckoo Bee in Canada are since 2015; increased sampling in previously un-surveyed areas may prove fruitful in the future. Recent records of Macropis Cuckoo Bee posted to iNaturalist from Canada (1 observation) and the United States (3 observations) support the worthwhileness of photo-based surveys for this species, its host bee, and the associated host food plants.

Severe fragmentation

A taxon can be considered to be severely fragmented if most (> 50%) individuals or most (> 50%) of the total area occupied (as a proxy for number of individuals) is in habitat patches that are both (a) smaller than would be required to support a viable subpopulation and (b) separated from other habitat patches by a distance larger than the species can be expected to disperse and where a species has a restricted distribution (that is, IAO < 2000 km²). It is unknown if Macropis Cuckoo Bee subpopulations meet the definition of severely fragmented. Both Macropis Cuckoo Bee and its host bee likely have poor dispersal ability due to their relatively small size, and a low number of separate and isolated extant subpopulations, especially across areas that do not support populations of L. ciliata and/or L. terrestris. However, as much of the potential range of Macropis Cuckoo Bee (and its host bee) have not been surveyed in Canada (Figure 4), there is insufficient information to conclude severe fragmentation.

Rescue effect

Macropis Cuckoo Bee is a small bee and does not appear to have high dispersal ability. The species is likely to remain close to host bee subpopulations, which are also limited to habitats with its host’s food plant(s). Given the extreme rarity of this species evidenced by past and recent collection records and the possible fragmented nature of the wetland habitat or other habitats supporting the floral host of its host bee, the chances of natural recolonization are likely minimal.

Threats

Historical, long-term, and continuing habitat trends

Habitat trends for Macropis Cuckoo Bee are linked to its host bee and host’s food plants (L. ciliata and L. terrestris), which are not at risk. Some host plant subpopulations may have undergone declines in southern parts of both Macropis Cuckoo Bee and its host bee’s geographic ranges. Wetland habitats continue to decline across the range of Macropis Cuckoo Bee. For example, in southern Ontario, wetlands have declined to 80% of their historical extent and what remains is projected to decline by more than 5% per year (Snell 1989). Invasive non-native plants, such as European Common Reed (Phragmites australis subsp. australis), continue to spread. In Nova Scotia, there has been extensive wetland development to urban areas and cranberry farms in the Annapolis Valley over the past few decades. In non-wetland or moist habitats supporting Lysimachia spp., non-native thistles (Cirsium spp.) and Leafy Spurge (Euphorbia esula) may also compete with floral hosts.

Current and projected future threats

The nature, scope, and severity of threats to Macropis Cuckoo Bee are tallied in Table 4 and described in Appendix 1, following the IUCN-CMP (International Union for the Conservation of Nature – Conservation Measures Partnership) unified threats classification system (see Salafsky et al. 2008 for definitions and Master et al. 2012 for guidelines). The threat assessment process consists of assessing impacts for each of 11 main threat categories, based on the scope (proportion of population exposed to the threat over the next 10-year period), severity (predicted population decline within the scope during the next 10 years or 3 generations, whichever is longer, up to ~100 years), and timing of each threat. The overall threat impact is calculated by considering the separate impacts of all threat categories and can be adjusted by the species experts participating in the threat’s evaluation.

The overall impact for Macropis Cuckoo Bee is medium-low, corresponding to an anticipated decline of < 1 and up to 30% over the next ten years. These values are to be interpreted with caution, as they may be based on subjective information, such as expert opinion, although efforts have been made to corroborate the scores with available studies and quantitative data.

The main threats to Macropis Cuckoo Bee are inferred and are those that impact the host bee’s food plants. The loss and degradation of appropriate host’s food plant habitat, which includes swamps, and stream, pond, and lake margins (Ray 1956) may impact host bee and Macropis Cuckoo Bee subpopulations. For example, the continued spread of non-native and invasive plants such as Purple Loosestrife (Lythrum salicaria) and European Common Reed change the host bee’s habitat. These threats primarily fall under other ecosystem modifications (7.3). Threats applicable to each subpopulation are in Table 4.

^a An extant subpopulation refers to some evidence of presence of single or multiple specimens ideally with evidence of on-site breeding (although difficult to determine with Macropis Cuckoo Bee) at a given site with potential breeding habitat. Evidence is derived from reliable published observation or collection data; unpublished, though documented (that is, government or agency reports, web sites) observation or collection data; or museum specimen information. The record has been documented within the last 20 years or there is no reason to suspect the species has been extirpated from the site (for example, the habitat is still intact, low or no threats) (definition edited from NatureServe 2022).

^b A historical subpopulation refers to a record where more than 20 years have passed since the last credible record of Macropis Cuckoo Bee. There is a possibility the species may remain at this site based on known historical occurrences, and there is still some hope of rediscovery. Examples of evidence include (1) that a species has not been documented despite some searching and/or some evidence of significant habitat loss or degradation; (2) that a species has been searched for unsuccessfully, but not thoroughly enough to presume that it is extirpated from this site. Most historical records for Macropis Cuckoo Bee are vague, or refer to a town, however most of these occurrences are surrounded with natural habitat where the bee could remain.

Annual and perennial non-timber crops (IUCN no. 2.1; threat impact low)

The host bee food plants occur in a wide range of habitats, including ephemeral wetlands and wet habitats. The conversion of ephemeral wetlands as well as permanent wetlands (for example, ditches, swamps, lake margins), and the cumulative loss, reduction and fragmentation of habitat contribute to the decline of Macropis Cuckoo Bee subpopulations. This includes the conversion of natural areas to agriculture or intensification of existing agricultural areas.

Different provinces have different wetland policies. For example, Saskatchewan does not have a wetland policy that prevents the draining of agricultural areas and the conversion for agriculture is ongoing. Although Saskatchewan may not be a large portion of the range, the impact could be high because wetland conversion for agriculture is large.

By contrast, Alberta does have a wetland policy (ESRD 2013), which provides strategic direction and tools to conserve, restore, protect and manage Alberta’s wetlands. The policy also describes the province’s commitment to maintain wetlands by avoiding, minimizing, and replacing lost wetland areas when avoidance is not possible. Alberta’s Water Act also provides guidance on wetland assessment, delineation, mitigation, and replacement, and applications are required for any activities that impact wetlands.

In Nova Scotia, a wetland conservation policy (DECC 2019) applicable to large developments requires an environmental assessment (EA). EAs can include multiple developments in one application (for example, including agricultural clearing, mines, wind turbines and other forms) and it is difficult to separate impacts from each development apart. This new wetland policy does not apply to historical sites, and it will be at the discretion of consultants working under the wetland alteration proposal to detect whether Macropis Cuckoo Bee is present or not (through the purview of wetlands biologists; the work will not be reviewed by the appropriate government division or species at risk biologists).

In Manitoba, a lot of agricultural areas are managed or wetlands drained, and in some areas there is potential for “tile drainage.” Even after wetland conversion, agricultural practices can impact small habitat patches. For example, ditches are cleared, and ditchwater is used for irrigation.

Approximately 30% of Ontario are wetlands (OMNR 2017). The province has a wetland policy; however, the policy relies on best management practices during development projects. “All of the other species (L. terrestris, L. thyrsiflora, L. ciliata, and L. quadriflora) are wetland plants, and wetlands cover 80% of their historical extent in southern Ontario and the remainder are projected to be declining by more than 5% per year” (Snell 1989).

The New Brunswick Wetlands Conservation Policy (2002) aims to prevent the loss of Provincially Significant Wetland (PSW) habitat and achieve the goal of no net loss of wetland function for all other wetlands. A Watercourse and Wetland Alteration (WAWA) permit will be required for any alteration in or within 30 metres of a watercourse or wetland (based on the definitions in the New Brunswick Clean Water Act). All wetlands are regulated based on their presence on the ground, regardless of whether they are identified on the WAWA Reference Map or not.

Other ecosystem modifications (IUCN no. 7.3; threat impact low)

Ecosystem modifications from the gradual spread of non-native and invasive weeds such as Purple Loosestrife and European Common Reed are known to impact wetlands and host food plants (for example, L. ciliata and L. terrestris) growing within that habitat. The growth of invasive/non-native plants has an impact on butterflies which are host’s food plant specialists (Burghardt et al. 2010) and this impact may be similar with other host’s food plant specialists.

European Common Reed is a dense growing species and a single plant can quickly spread into open wetland areas at a rate of 1 to 2m per year, with annual cane shoots that reach 2 to 4m (OMNR 2011). Dead canes can remain standing for 3 to 4 years, preventing any shade-intolerant plants from growing under these stems (OMNR 2011). The plant can grow dense monocultural stands, take over smaller wetlands or ephemeral areas and disperses through seeds or rhizome fragments (Lee et al. 2025). European Common Reed releases a toxin from its roots that can kill plants growing nearby (OMNR 2011).

Four species of Lysimachia spp. are introduced to North America and it is unknown whether these plants are suitable food plants for the host bee. If they are not suitable floral hosts and they are able to outcompete native Lysimachia spp. in appropriate habitat, they would be a threat to the Macropis Cuckoo Bee.

Agricultural and forestry effluents (IUCN no. 9.3; threat impact low)

Because they occur in wetland margins, the host bee and Macropis Cuckoo Bee may be especially vulnerable to insecticides used for mosquito control (Ascher 2005). Neonicotinoids also accumulate in wetlands.

In the European Food Safety Authority’s (2013) risk assessment, worker bees, queens, and larvae of bumble bees and adult females and larvae of solitary bees were categories of bees that are most exposed to pesticides via ingestion. Specifically, the larvae of solitary bees (that is, M. nuda and Macropis Cuckoo Bees) are provisioned with large amounts of unprocessed pollen and are more exposed to residues in pollen and oil. Additionally, solitary bees may be further exposed by contact with nesting material (that is, soil or floral resources).

One of the most recent Macropis Cuckoo Bee records in Saskatchewan was close to rangeland and adjacent agriculture; the southern part of the cuckoo bee’s range could be susceptible to pesticide drift. In Manitoba, Macropis Cuckoo Bee was recorded from a roadside ditch; ditches often have concentrated pesticide residues and thus encountering pollutants is possible. In Alberta, although the record is from Elk Island National Park, the area is surrounded by agriculture and may be impacted by neonicotinoid accumulation from nearby agricultural areas. In Nova Scotia, New Brunswick, and parts of Ontario, this is also possible.

Habitat shifting and alteration (IUCN no. 11.1; threat impact unknown)

Climate change may disrupt the relationships between Macropis Cuckoo Bee, the host bee and the host’s food plant; responses will differ between species (see Buckner and Danforth 2022). As temperatures rise, flowers may bloom earlier or bees may emerge earlier in the spring in response to warm daytime temperatures; either situation potentially creates a mismatch in timing between when flowers produce oil and pollen and when host bees are able to exploit these floral resources. Buckner and Danforth (2022) suggest climatic warming is likely to result in shifts of both L. ciliata and M. nuda in the United States, and that Canada will potentially become a higher proportion of Macropis Cuckoo Bee’s global range. This study did not consider that L. terrestris is a host bee food plant.

Droughts (IUCN no. 11.2; threat impact low)

Hotter, drier summers (drought) may lead to increased stress on flowering plants and may affect the quantity and/or quality of floral resources for Macropis spp. (Phillips et al. 2018). Many of the Macropis Cuckoo Bee records are linked to wetland habitats, and prolonged hotter summers may lead to ephemeral wetlands drying out earlier, thereby impacting floral host blooms and host bee emergence.

In general, Lysimachia spp. habitats have high spring moisture and as the summer months pass, this habitat dries out towards fall. However, these ephemeral wetland areas appear to be changing; deeper water zones may hold some plants, but shallow water zones no longer hold moisture, sometimes for a few consecutive years, and the cumulative impact is likely changing the wetlands and host plant(s) health. For example, there is less running water throughout ephemeral wetlands within Wood Mountain, Saskatchewan, and as the summer progresses, and this could lead to loss and drying out of these sites (Sheffield pers. comm. 2024). Whether this has an impact to host food plant subpopulations are unknown and in some areas, host food plants appear to survive in non-wetland areas. With the droughts in Saskatchewan, especially in the past 4 to 10 years, the wetlands are starting the spring season dry and may be getting a snowmelt pool, but it is not holding water in the spring season (Semmler pers. comm. 2024). In the Maritimes, L. terrestris and L. ciliata grows in a wide range of wetland areas, and droughts may not be a significant threat to host bee food plants within this region (Klymko pers. comm. 2024).

The scope of this threat is Restricted-Small (1 to 30%) because host bee food plants remain apparently viable in habitats that dry up early in the summer months, as well as those that remain moist. However, the host bee nest sites may be impacted by a lack of moisture, and impacts to the host bee and Macropis Cuckoo Bee may still occur. The severity of this threat is also considered low (1 to 10%).

Air-borne pollutants (IUCN no. 9.3; threat impact unknown)

Forest fire smoke may have an impact on insect abundance. It is anecdotal, but bee activity appears to decline with forest fire smoke (Klymko pers. comm. 2024; Sheffield pers. comm. 2024). Smoke is scored under this threat (not under 7.1). Additional information is needed to determine whether forest fire smoke has an impact on Macropis Cuckoo Bee, its host bee or host bee food plant abundance and distribution.

Number of threat locations

The most serious plausible threat to Macropis Cuckoo Bee is ecosystem modifications to the species’ habitat compounded with prolonged droughts due to climate change. There is a minimum of eight extant subpopulations, based on the number of sites found in the past 20 years, and up to seventeen locations (Table 1), if we assume all known subpopulations could potentially be extant (based on the assumption that the habitat is still intact; low abundance and probability of capturing the bee). This means that, if each subpopulation is small and localized, they would each represent a threat-based location. This corresponds to a minimum of eight locations^{Footnote 5} proposed for Macropis Cuckoo Bee. It is not possible to place a precise upper limit on the number of subpopulations since data are so sparse, but the number is probably more than seventeen, which includes all known subpopulations recorded within Canada. There is extensive potential Macropis Cuckoo Bee habitat in Canada that has not been surveyed, and extensive areas likely remain intact.

Protection, status, and recovery activities

Legal protection and status

Macropis Cuckoo Bee was assessed by COSEWIC as Endangered in May 2011 and listed on Schedule 1 of the federal Species at Risk Act (SARA) in 2018. It was not considered possible to identify critical habitat; the recovery of the species was determined to not be biologically and technically feasible under SARA (ECCC 2021).

Macropis Cuckoo Bee is listed as endangered under the Nova Scotia Endangered Species Act. The Committee on the Status of Species at Risk in Ontario assessed Macropis Cuckoo Bee as Data Deficient in 2010; the species does not receive protection under the Ontario Endangered Species Act. The species is not protected under Alberta’s Wildlife Act (RSA 2000, c. W-10), Manitoba’s Endangered Species and Ecosystems Act (C.C.S.M. c. E111, Regulation 25/38), nor the Loi sur les espèces menacées ou vulnérables DU Québec (Act respecting threatened or vulnerable species E-12.01 r.2).

The host bee and host’s food plants have a broad geographic range from Nova Scotia to British Columbia and are not legally protected within these jurisdictions.

The Manitoba Water Rights Act includes wetlands and was amended in 2019. The Water Rights Regulation “reduces red tape for lower-risk, lower-impact drainage and water retention works, focusses regulatory review on higher-impact, higher-risk projects, and increases protection for Manitoba’s wetlands. The shift toward streamlined drainage authorizations and no net loss of wetlands will support the sustainable management of water in Manitoba” (Manitoba Environment and Climate Change 2025).

Non-legal status and ranks

The conservation status ranks for Macropis Cuckoo Bee its host bee and host bees food plants in Canada, globally and provincially are listed in Table 3. The national conservation status rank in the United States is NH (Possibly Extirpated) and state status ranks are Connecticut: S1, Maryland: SH, Massachusetts: S2, New Jersey: SNR, New York: S1, North Carolina: SNR, Pennsylvania: SNR, Virginia: SH, Wisconsin: S1 (NatureServe 2025).

The Xerces Society has listed Macropis Cuckoo Bee in their Red List of pollinators (Ascher 2005).

Land tenure and ownership

Two specimens of Macropis Cuckoo Bee have been collected on private land near Middleton, Nova Scotia (Sheffield et al. 2004). Since 2008, this site appears to have undergone natural succession, with very little open space for L. terrestris (Klymko pers. comm. 2022), although surrounding areas appear to have host’s food plants and host bee subpopulations. The Alberta specimen was collected in Elk Island National Park and protected under the National Parks Act. The Nova Scotia Wetland Conservation Policy (2011) and wetland stewardship benefits the Macropis Cuckoo Bee, its host bee, and its bee host food plant habitat in this province.

Recovery activities

No specific recovery activities have been undertaken for Macropis Cuckoo Bee in Canada since the first COSEWIC (2011) assessment. Inventory for Macropis Cuckoo Bee from 2011 to 2024 includes:

• A review of all specimens of Macropis Cuckoo Bee, its host bees (Macropis spp.) and its host’s food plants (Lysimachia spp.) in Canada (Sheffield and Heron 2018)
• Recent surveys and confirmation of the species in Manitoba (Gibbs et al. 2021) plus new unpublished records for 2022
• Recent surveys at historical subpopulation sites in Saskatchewan (that is, Wood Mountain, Wallwort) from 2013 and 2022. Techniques included hand netting, pan traps and malaise traps at Wood Mountain, and hand nets and photography within the Wallwort area in 2022. No specimens recorded though the host bee’s food plants were present at both sites, and the host bee was collected near the latter (Greenwater Lake Provincial Park). Suitable habitat exists in both sites, and it is assumed that the Macropis Cuckoo Bee is likely still present
• Recent surveys (2024) in Elk Island National Park including some information on the timing of flowering of the host bee’s food plant (Neame pers. comm. 2024)

Information sources

Alexander, B., and J.G. Rozen, Jr. 1987. Ovaries, ovarioles, and oocytes in parasitic bees (Hymenoptera: Apoidea). Pan-Pacific Entomologist 63:155-164.

Ascher, J.S. 2005. Species Profile: Epeoloides pilosula. In Shepherd, M. D., D. M. Vaughan, and S. H. Black (Eds). Red List of Pollinator Insects of North America. Portland, OR: The Xerces Society for Invertebrate Conservation.

Ascher, J.S., and J. Pickering. 2023. Discover Life bee species guide and world checklist (Hymenoptera: Apidae: Anthophila). [Accessed February 18, 2025].

Audet, T., N. Romero, and M. Richards. 2021. Negative effects of early spring mowing on a bee community: a case study in the Niagara Region. Journal of the Entomological Society of Ontario 152:39-55.

Bogusch, P. 2005. Biology of the cleptoparasitc bee Epeoloides coecutiens (Hymenoptera:Apidae:Osirini). Journal of the Kansas Entomological Society 78:1-12.

BOLD Systems. 2025. [accessed February 24, 2025].

Britton, N.L., and A. Brown. 1913. An Illustrated Flora of the Northern United States and Canada. 2^nd Edition. Dover Publications, New York, NY.

Buckner, M.A., and B.N. Danforth. 2022. Climate-driven range shifts of a rare specialist bee, Macropis nuda (Melittidae) and its host’s food plant Lysimachia ciliata (Primulaceae). Global Ecology and Conservation 37(2022) e02180. [Accessed February 24, 2025].

Burghardt, K.T., D.W. Tallamy, C. Phillips. and K.J. Shropshire. 2010. Non-native plants reduce abundance, richness, and host specialization in lepidopteran communities. Ecosphere 1:1-22.

Canadian Council of Ecological Areas. 2014. Terrestrial ecozone map. [accessed February 17, 2025].

Cane, J.H., G.C. Eickwort, F.R. Wesley, and J. Spielholz. 1983. Foraging, grooming, and mating behaviors of Macropis nuda (Hymenoptera:Melittidae) and use of Lysimachia ciliata (Primulaceae) oils in larval provisions. American Midland Naturalist 110:257-264.

Cardinal, S., J. Straka, and B.N. Danforth. 2010. Comprehensive phylogeny of apid bees reveals the evolutionary origins and antiquity of cleptoparasitism. Proceedings of the National Academy of Sciences 107(37):16207-16211.

Celary, W. 2004. A comparative study of the biology of Macropis fulvipes (Fabricius, 1804) and Macropis europaea Warncke, 1973 (Hymenoptera:Apoidea:Melittidae). Folia biologica 52:81-85.

Coffey, V.J., and S.B.J. Jones. 1980. Biosystematics of Lysimachia section Seleucia (Primulaceae). Brittonia 32:309-322.

COSEWIC. 2011. COSEWIC assessment and status report on the Macropis Cuckoo Bee Epeoloides pilosulus in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. ix + 25 pp.

Cresson, E.T. 1878. Descriptions of new North American Hymenoptera in the collection of the American Entomological Society. Transactions of the American Entomological Society 7:61-136.

DECC (Nova Scotia Department of Environment and Climate Change). 2019. Nova Scotia Wetland Conservation Policy. Wetlands Program, Government of Nova Scotia. 27pp. [Accessed February 22, 2025].

Dötterl, S. 2008. Antennal responses of an oligolectic bee and its cleptoparasite to plant volatiles. Plant Signaling and Behavior 3:296-297.

Dötterl, S., and I. Schäffler. 2007. Flower scent of floral oil-producing Lysimachia punctata as attractant for the oil-bee Macropis fulvipes. Journal of Chemical Ecology 33:441-445.

Ducke, A. 1909. Contributions à la connaissance des Hyménoptères des deux Amériques. Revue d’Entomologie 27:28‑55.

Environment and Climate Change Canada. 2021. Recovery Strategy for the Macropis Cuckoo Bee (Epeoloides pilosulus) in Canada [Proposed]. Species at Risk Act Recovery Strategy Series. Environment and Climate Change Canada, Ottawa. vii + 12 pp.

ESRD (Alberta Environment and Sustainable Resource Development). 2013. Alberta Wetland Policy, Government of Alberta, 25pp. [accessed February 22, 2025].

European Food Safety Authority. 2013. Conclusion on the peer review of the pesticide risk assessment for bees for the active substance imidacloprid. EFSA Journal 2013;11(1):3068. [55 pp.] doi:10.2903/j.efsa.2013.3068.

Fabricius, J.C. 1775. Systema entomologiae sistens insectorum classes, ordines, genera, species, adiectis synonymis, locis, descriptionibus, observationibus. Karte 30u Flensburgi et Lipsiae. 832 pp.

Fernald, M.L. 1950. Gray’s Manual of Botany: A Handbook of the Flowering Plants and Ferns of the Central and Northeastern United States and Adjacent Canada. 8^th Edition. Dioscorides Press, Portland, OR.

Gathmann, A., and T. Tscharntke. 2002. Foraging ranges of solitary bees. Journal of Animal Ecology 71:757-764.

GBIF 2025a. GBIF.org (16 February 2025) GBIF Occurrence Download

GBIF 2025b. GBIF.org (16 February 2025) GBIF Occurrence Download

GBIF 2025c. GBIF.org (16 February 2025) GBIF Occurrence Download

GBIF 2025d. GBIF.org (16 February 2025) GBIF Occurrence Download

GBIF 2025e. GBIF.org (16 February 2025) GBIF Occurrence Download

GBIF 2025f. GBIF.org (16 February 2025) GBIF Occurrence Download

GBIF 2025g. GBIF.org (17 February 2025) GBIF Occurrence Download

GBIF 2025h. GBIF.org (17 February 2025) GBIF Occurrence Download

Gerner, E.E., and R.D. Sargent. 2022. Local plant richness predicts bee abundance and diversity in a study of urban residential yards. Basic and Applied Ecology 58:64-73.

Gibbs, J. 2024. Personal communication to Cory Sheffield (email). August 2024. Associate Professor, Department of Entomology, Curator - J. B. Wallis / R. E. Roughley Museum of Entomology, University of Manitoba (Fort Garry campus), Winnipeg, MB.

Gibbs, J., E. Hanuschuk, R. Miller, M. Dubois, M. Martini, S. Robinson, P. Nakagawa, C.S. Sheffield, and T. Onuferko. 2023. A checklist of the bees (Hymenoptera:Apoidea) of Manitoba, Canada. The Canadian Entomologist 155:E3.

Gibbs, J., E.J. Hanuschuk, and S. Shukla-Bergen. 2021. Rediscovery of the rare bee Epeoloides pilosulus in Manitoba (Hymenoptera:Apidae). Journal of the Kansas Entomological Society 93(2):176-182.

IUCN (2001, 2012). IUCN Red List Categories and Criteria: Version 3.1. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, U.K. [accessed February 17, 2025].

Klymko, J. 2024. Personal communication to Cory Sheffield (email). August 2024. Zoologist, Atlantic Conservation Data Centre, Sackville, NB.

Krombein, K.V., P.D. Hurd, Jr., D.R. Smith, and B.D. Burks. 1979. Catalog of Hymenoptera in America North of Mexico. Volume 2. Apocrita (Aculeata). Smithsonian Institution Press, Washington.

Lee, S.F., M.K. McCormick, T.J. Mozdzer, K. Clay, and E.C. Farrer. 2025. Regional variation in Phragmites australis reproductive traits and seedling performance in North America. Wetlands 45(19)

Linsley, E.G., and C.D. Michener. 1939. A generic revision of the North American Nomadidae. Transactions of the American Entomological Society 65: 265-305.

MacDonald, M., and B. Freedman. 2011. Two vascular plants new to Nova Scotia: Yellow Glandweed (Parentucellia viscosa (L.) Caruel) and Whorled Loosestrife (Lysimachia quadrifolia L.). The Canadian Field-Naturalist 125(1):63-64.

Malyshev, S.I. 1929. The nesting habits of Macropis Pz. (Hym. Apoidea). EOS 5:97‑109.

Manitoba Environment and Climate Change. 2025. Drainage and Water Control. [accessed February 15, 2025]

Martins, A.C., F.V. Freitas, L.C. Rocha-Filho, M.G. Branstetter, A.J.C. Aguiar, E.A.B. Almeida, and T. Vasconcelos. 2025. Host-cleptoparasite biogeographical congruence through time: the case of cuckoo oil bees. Journal of Biogeography

Master, L.L., D. Faber-Langendoen, R. Bittman, G.A. Hammerson, B. Heidel, L. Ramsay, K. Snow, A. Teucher, and A. Tomaino. 2012. NatureServe conservation status assessments: factors for evaluating species and ecosystems risk. NatureServe, Arlington, Virginia.

Michener, C.D. 1938. A review of the American bees of the genus Macropis. Psyche 45:133-135.

Michener, C.D. 2000. The Bees of the World. Johns Hopkins University Press; Baltimore, MD. 913 pp.

Michener, C.D. 2007. The Bees of the World, Second Edition. Johns Hopkins University Press; Baltimore, MD.

Michener, C.D., R.J. McGinley, and B.N. Danforth. 1994. The Bee Genera of North and Central America (Hymenoptera:Apoidea). Washington, Smithsonian Institution Press.

Michez, D., and S. Patiny. 2005. World revision of the oil-collecting bee genus Macropis Panzer 1809 (Hymenoptera:Apoidea:Melittidae) with a description of a new species from Laos. Annales de la Société Entomologique de France 41:15-28.

Mitchell, T.B. 1960. Bees of the eastern United States. Volume I. North Carolina Agricultural Experiment Station Technical Bulletin 141.

Mitchell, T.B. 1962. Bees of the eastern United States. Volume II. North Carolina Agricultural Experiment Station Technical Bulletin 152.

Monsevièius, V. 2004. Comparison of three methods of sampling wild bees (Hymenoptera, Apoidea) in Èepkeliai Nature Reserve (South Lithuania). Ekologija 4:32-39.

NatureServe. 2025. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.827036/Epeoloides_pilosula [accessed August 11, 2025]

Neame, L. 2023. Personal communication to Cory Sheffield (email). August 2024. Biodiversity Policy Analyst, Alberta Environment and Parks, AB.

Neame, L. 2024. Personal communication to C. Sheffield. Biodiversity Policy Analyst, Alberta Environment and Protected Areas, Calgary, AB.

Nelson, C.J., C.M. Frost, and S.E. Nielsen. 2021. Narrow anthropogenic linear corridors increase the abundance, diversity, and movement of bees in boreal forests. Forest Ecology and Management 489:119044

New Brunswick Wetlands Conservation Policy. 2002. [accessed June 2, 2025].

Nova Scotia Wetland Conservation Policy. 2011 https://www.novascotia.ca/nse/wetland/conservation.policy.asp [accessed February 17, 2025].

OMNR (Ontario Ministry of Natural Resources and Forestry). 2017. A Wetland Conservation Strategy for Ontario 2017 to 2030. Queen’s Printer for Ontario. Toronto, ON. 52 pp.

OMNR (Ontario Ministry of Natural Resources). 2011. Invasive Phragmites – Best Management Practices. Ontario Ministry of Natural Resources, Peterborough, Ontario. 17 pp.

Packer, L., J.A. Genaro, and C.S. Sheffield. 2007. The bee genera of eastern Canada. Canadian Journal of Arthropod Identification 3:1-33.

Pekkarinen, A., Ø. Berg, I. Calabuig, L. Janzon, and J. Luig. 2003. Distribution and co-existence of the Macropis species and their cleptoparasite Epeoloides coecutiens (Fabr.) in NW Europe (Hymenoptera:Apoidea, Melittidae and Apidae). Entomologica Fennica 14:53-59.

Phillips, B.B, R.F. Shaw, M.J. Holland, E.L. Fry, R.D. Bardgett, J.M. Bullock, and J.L. Osborne. 2018. Drought reduces floral resources for pollinators. Global Change Biol., 24 (2018), pp. 3226-3235 Saskatchewan Conservation Data Centre. 2018. Taxa List: Invertebrates. [accessed February 17, 2025].

Popov, V.B. 1958. Peculiar features of correlated evolution of two genera of bees—Macropis and Epeoloides (Hymenoptera, Apoidea)—and a plant genus Lysimachia (Primulaceae). Entomological Review 37:499-519. [In Russian.]

Provancher, L. 1888. Additions et corrections au Volume II de la Faune entomologique du Canada traitant des hyménoptères. Quebec, C. Darveau. 475 pp.

Province of Alberta. 2000. Wildlife Act, RSA 2000, c W-10. [Accessed February 14, 2025].

Ratnasingham S., and P.D.N. Herbert. 2007. BOLD: The Barcode of Life Data System. Molecular Ecology Notes 7:355 to 364. [Accessed September 18, 2023].

Ratnasingham S., and P.D.N. Herbert 2013. A DNA-based registry for all animal species: the barcode index number (BIN) system. PLoS ONE 8(7): e66213. [Accessed September 18, 2023]

Ray, J.D., Jr. 1956. The genus Lysimachia in the New World. Illinois Biological Monographs 24:1-160.

Roig-Alsina, A. 1989. The tribe Osirini, its scope, classification, and revisions of the genera Parepeolus and Osirinus (Hymenoptera, Apoidea, Anthophoridae). University of Kansas Science Bulletin 54:1-23.

Rozen, J.G., Jr, and N.R. Jacobson. 1980. Biology and immature stages of Macropis nuda, including comparisons to related bees (Apoidea, Melittidae). American Museum Novitates 2702:1-11.

Rubens, C. 2019. Changes in composition and structure of a wild bee community and plant-pollinator interactions in South-Central Ontario over a forty-nine year period. MSc Thesis, University of Guelph, Guelph, Ontario, xi + 135 pp.

Salafsky, N., D. Salzer, A.J. Stattersfield, C. Hilton-Taylor, R. Neugarten, S.H.M. Butchart, B. Collen, N. Cox, L.L. Master, S. O’Connor, and D. Wilkie. 2008. A standard lexicon for biodiversity conservation: unified classifications of threats and actions. Conservation Biology 22:897-911.

Scoggan, H.J. 1979. The Flora of Canada. Part 4. Dicotyledoneae (Loasaceae to Compositae). National Museums of Canada, Ottawa, ON.

Semmler, S. 2024. Personal communication to Cory Sheffield (email) August 2024. Director, Living Prairie Museum, Winnipeg, MB.

Sharkey, J.K. 2022. Restoring rarities: the impact of habitat management and restoration on native bee communities in tallgrass prairie and oak savanna in southern Ontario. MSc Thesis, University of Guelph, xv + 153 pp.

Sheffield, C.S. 2008. Summer bees for spring crops? Potential problems with Megachile rotundata (Fab.) (Hymenoptera: Megachilidae) as a pollinator of lowbush blueberry (Ericaceae). Journal of the Kansas Entomological Society 81:276-287.

Sheffield, C.S. 2024. Personal communication to Jennifer Heron (email and phone) August 2024. Curator of Invertebrate Zoology, Royal Saskatchewan Museum, Regina, SK.

Sheffield C.S., and J. Heron. 2018. A new western Canadian record of Epeoloides pilosulus (Cresson), with discussion of ecological associations, distribution, and conservation status in Canada. Biodiversity Data Journal 6:e22837. doi: 10.3897/BDJ.6.e22837. PMID: 29686501; PMCID: PMC5911681.

Sheffield, C.S., and. J.M. Perron. 2014. Annotated catalogue of the bees described by Léon Provancher (Hymenoptera: Apoidea: Apiformes). Canadian Entomologist 146:117-169. doi:10.4039/tce.2013.64.

Sheffield, C.S., J. Heron, J. Gibbs, T.M. Onuferko, R. Oram, L. Best, N. deSilva, S. Dumesh, A. Pindar, and G. Rowe. 2017. Contribution of DNA barcoding to the study of the bees (Hymenoptera: Apoidea) of Canada: progress to date. The Canadian Entomologist 149:736-754 [accessed February 18, 2025].

Sheffield, C.S., P.D.N. Hebert, P.G. Kevan, and L. Packer. 2009. DNA barcoding a regional bee (Hymenoptera: Apoidea) fauna and its potential for ecological studies. Molecular Ecology Resources 9 (Suppl. 1):196-207.

Sheffield, C.S., S.M. Rigby, R.F. Smith, and P.G. Kevan. 2004. The rare cleptoparasitic bee Epeoloides pilosulus (Hymenoptera: Apoidea: Apidae) discovered in Nova Scotia, Canada, with distributional notes. Journal of the Kansas Entomological Society 77:161-164.

Simpson, B.B., J.L. Neff, and D.S. Seigler. 1983. Floral biology and floral rewards of Lysimachia (Primulaceae). American Midland Naturalist 110:249-256.

Sless, T.J.L., M.G. Branstetter, J.P. Gillung, E.A. Krichilsky, K.B. Tobin, J. Straka, J.G. Rozen, F.V. Freitas, A.C. Martins, S. Bossert, J.B. Searle, and B.N. Danforth. 2021. Phylogenetic relationships and the evolution of host preferences in the largest clade of brood parasitic bees (Apidae: Nomadinae). Molecular Phylogenetics and Evolution 166: 107326

Snell, E.A. 1989. Recent wetland loss trends in southern Ontario. Pp. 183-197 in Bardecki, M.J. and Patterson, N, eds. Wetlands: inertia or momentum. Conference Proceedings. Federation of Ontario Naturalists, Don Mills.

Snelling, R.R., and G.I. Stage. 1995. A revision of the Nearctic Melittidae: the subfamily Melittinae (Hymenoptera: Apoidea). Natural History Museum of Los Angeles County Contributions in Science 451:19-31.

Statistics Canada. 2018. Ecological Land Classification, 2017. Government of Canada Catalogue no. 12-607-X.

Stephen, W.P., G.E. Bohart, and P.F. Torchio. 1969. The Biology and External Morphology of Bees with a Synopsis of the Genera of Northwestern America. Agricultural Experiment Station / Oregon State University; Corvallis, OR.

Straka, J., and P. Bogusch. 2007. Description of immature stages of cleptoparasitic bees Epeoloides coecutiens and Leiopodus trochantericus (Hymenoptera: Apidae: Osirini, Protepeolini) with remarks to their unusual biology. Entomologica Fennica 18:242-254.

Swenk, M.H. 1907. The bees of Nebraska. III. Entomological News 18:293-300.

Vickruck, J.L., L.R. Best, M.P. Gavin, J.H. Devries, and P. Galpern. 2019. Pothole wetlands provide reservoir habitat for native bees in prairie croplands. Biological Conservation 232: 43-50 [accessed February 18, 2025].

Vogel, S. 1976. Lysimachia: Ölblumen der Holarktis. Naturwissenschaften 63:44-45.

Vogel, S. 1986. Ölblumen und ölsammelnde Bienen. Zweite Floge. Lysimachia und Macropis. Tropische und Subtropische Pflanzenwelt 54:147-312.

Wagner, D.L., and J.S. Ascher. 2008. Rediscovery of Epeoloides pilosulus (Cresson) (Hymenoptera: Apidae) in New England. Journal of the Kansas Entomological Society 81:81-83.

Zayed, A., and L. Packer. 2005. Complementary sex determination substantially increases extinction proneness of haplodiploid populations. Proceedings of the National Academy of Sciences U.S.A. 102:10742-10746.

Collections examined

The following collections were queried for Canadian specimens Macropis Cuckoo Be:

• American Museum of Natural History (AMNH), 200 Central Park West, New York, New York 10024-5102
• Buffalo Museum of Science, 1020 Humboldt Parkway, Buffalo, New York 14211 (Paige Langle)
• Canadian Museum of Nature, The Natural Heritage Campus, 1740 Pink Road, Gatineau, Quebec, J9J 3N7 (Robert Anderson)
• Canadian National Collection (CNC) of Insects, Arachnids and Nematodes, Agriculture and Agri-Food Canada, K.W. Neatby Building, 960 Carling Avenue, Ottawa, Ontario K1A 0C6
• Discover Life https://www.discoverlife.org/
• E.H. Strickland Entomological Museum, Department of Biological Sciences, University of Alberta, Edmonton, Alberta
• Great Lakes Forestry Centre (NRC-FRS), Natural Resources Canada, 1219 Queen Street East, Sault Ste Marie, Ontario P6A 2E5 (Kevin Barber)
• iNaturalist www.inaturalist.ca
• Lyman Entomological Museum, McGill University, 21111 Lakeshore Road, Ste-Anne-de-Bellevue, Quebec H9X 3V9 (Stephanie Boucher)
• Michigan State University, Albert J. Cook Arthropod Research Collection, 426 Auditorium Road, East Lansing, Michigan 48824 (online database search - https://doi.org/10.15468/dl.h8pebv)
• Milwaukee Public Museum Invertebrate Zoology Collection (MPM), 800 West Wells Street, Milwaukee, Wisconsin 53233 (online database search)
• Natural History Museum (NHM), Cromwell Road, London, England SW7 5BD (online database search)
• Northern Forestry Centre (NRC-FRS), Natural Resources Canada, 5320-122^nd Street, Edmonton, Alberta T6H 3S5. (Greg Pohl)
• Nova Scotia Insectary, Shubenacadie, Nova Scotia
• Nova Scotia Museum of Natural History, Halifax, Nova Scotia
• Packer's Apoidea Collection, Department of Biology, York University, Toronto, Ontario
• Royal Alberta Museum, 12845-102^nd Avenue, Edmonton, Alberta T5N 0M6 (Tyler Cobb)
• Royal British Columbia Museum, 675 Belleville Street, Victoria, British Columbia V8W 9W2 (online database search)
• Royal Ontario Museum (ROM), 100 Queen’s Park, Toronto, Ontario M5S 2C6 (Brad Hubley)
• Smithsonian National Museum of Natural History (USNM), 10^th Street and Constitution Avenue, Washington, D.C. 20560 (online database search)
• Snow Entomological Collection, Division of Entomology, University of Kansas, Lawrence, Kansas U.S.A
• Spencer Entomological Collection, Beaty Biodiversity Museum, University of British Columbia, 2212 Main Hall, Vancouver, British Columbia V6T 1Z4 (online database search)
• Strickland Entomological Museum, University of Alberta, Edmonton, Alberta T6G 2E9 (online database search)
• Texas A and M University, Department of Entomology, TAMU 2475, College Station, Texas 77843-2475 (James McDermott)
• The insect collection at Agriculture and Agri-Food Canada, Kentville, Nova Scotia
• The Manitoba Museum, 190 Rupert Avenue Winnipeg, Manitoba R3B 0N2 (Randall Mooi)
• Toronto Entomologists’ Association (TEA) Moth Atlas (online database search)
• University of Georgia Collection of Arthropods (UGCA), Natural History Museum Building, Athens, Georgia 30602-7882 (online database search)
• University of Guelph, Guelph, Ontario N1G 2W1 (Steve Marshall)
• University of Guelph Insect Collection, Department of Environmental Biology, University of Guelph, Guelph, Ontario
• University of Minnesota Insect Collection (UMSP), Department of Entomology, 219 Hodson Hall, 1980 Folwell Avenue, University of Minnesota, St. Paul, Minnesota 55108 (online database search)
• USDA-ARS Bee Biology and Systematics Laboratory, Logan, Utah U.S.A
• Wallis-Roughly Museum of Entomology, Department of Entomology, Faculty of Agricultural and Food Sciences, University of Manitoba, Winnipeg, Manitoba
• Western University, Department of Biology, Biological and Geological Sciences Building, London, ON N6A 5B7 (Nina Zitani)
• Yale Peabody Museum of Natural History (PMNH), 170 Whitney Avenue, New Haven, Connecticut 06511 (online database search)

Authorities contacted

• Anctil, Alexandre. Coordinator, Centre de données sur le patrimoine naturel du Québec, Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs, Quebec, Canada
• Anderson, Robert (Bob). Research Scientist, Canadian Museum of Nature - Natural Heritage Campus, Ottawa, Ontario
• Bennett, Andrew. Research Scientist, Agriculture and Agri-Food Canada, Ottawa, Ontario
• Bouchard, Nancy. Analyst, Comité conjoint de chasse, de pêche et de piégeage, Hunting, Fishing and Trapping Coordinating Committee, Montreal, Quebec
• Cannings, Syd. Species at Risk Biologist, Canadian Wildlife Service, Environment and Climate Change Canada / Government of Canada, Whitehorse, Canada
• Currie, Doug. Curator of Entomology, Department of Natural History, Royal Ontario Museum, Toronto, Ontario
• de Forest, Leah. Species Conservation Specialist, Conservation Programs Branch, Parks Canada Agency, Winnipeg, Manitoba
• Desrosiers, Nathalie. Direction générale des écosystèmes et des espèces menacées ou vulnérables, Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs, Québec, Quebec
• Favret, Colin. Curator, Ouellet-Robert Entomological Collection, Université de Montréal, Montreal, Quebec
• Gauthier, Isabelle. Coordonnatrice provinciale des espèces fauniques menacées et vulnérables, Direction générale des écosystèmes et des espèces menacées ou vulnérables, Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs, Québec, Quebec
• Hubley, Brad. Entomology Technician, Royal Ontario Museum, Department of Natural History, Toronto, Ontario
• Jones, Colin. Provincial Zoologist – Invertebrates, Ontario Natural Heritage Information Centre, Northern Development, Mines, Natural Resources and Forestry, Peterborough, Ontario
• Lonsdale, Owen, Collection Manager, Canadian National Collection of Insects, Arachnids and Nematodes and National Identification Service, Agriculture and Agri-
• Food Canada, Ottawa, Ontario
• Paiero, Steven. Curator, University of Guelph Insect Collection, Guelph, Ontario
• Randall Mooi. Curator of Zoology, Manitoba Museum, Winnipeg, Manitoba
• Soliman, Dina. Senior Data Management Specialist, Informatics, Centre for Biodiversity Genomics, University of Guelph, Guelph, Ontario
• Sones, Jayme. Collections Manager, Centre for Biodiversity Genomics Collections, University of Guelph, Guelph, Ontario

Acknowledgements

Funding for the preparation of this report was provided by Environment and Climate Change Canada. Those listed under Authorities provided valuable data and/or advice.

From the first report, thanks to Lisa Harkness (Acadia University, Wolfville, NS) for her assistance in surveying for Macropis Cuckoo Bee in Nova Scotia in 2008; Dr. John Ascher, American Museum of Natural History, New York, NY through earlier correspondence on the occurrence of this species; Dr. Laurence Packer, York University, Toronto, ON for support and advice throughout the duration of this study; Dr. Paul Catling (Agriculture and Agri-Food Canada, Ottawa, ON) for additional information on Lysimachia spp. in Canada, and helpful comments and suggestions during the preparation of the status report. Thanks are also due to others who have helped collect data on the distribution of Macropis nuda and Macropis Cuckoo Bee in Nova Scotia: Sue Westby, Kim Jansen, Meg Hainstock (all formerly at Agriculture and Agri-Food Canada, Kentville, NS). For this updated status report, thanks to Jennifer Heron, Dr. Jason Gibbs (University of Manitoba), and Michael Pelikan for the front cover photo of the live specimen.

Ryan Collins (COSEWIC Secretariat) completed the maps for this report and Joanna James (COSEWIC Secretariat) provided scientific and technical advice. Members of the Arthropods Specialist Subcommittee provided review: Robert Buchkowski, Sydney G. Cannings, Lisa Capar, Jeremy deWaard, Allan Harris, Colin Jones, John Klymko, Jayme Lewthwaite, Jessica Linton, Dawn Marks, Julia Mlynarek, Tyler D. Nelson, Jeff Ogden, Robert J. Pivar, Leah Ramsay, Brian Starzomski and Dan Benoit (ATK subcommittee).

Biographical summary of report writer

Cory S. Sheffield has been studying bees and pollination since 1993, starting with his undergraduate thesis project at Acadia University in Nova Scotia. His master’s research studied insect-plant interactions at Acadia University and Agriculture and Agri-Food Canada in Kentville, Nova Scotia, followed by a PhD at the University of Guelph, Ontario. These studies focused on the bee fauna of Nova Scotia, including their diversity and contributions to crop pollination. Cory then worked on post-doctoral studies of bee taxonomy and DNA barcoding, followed by a research associate position in bee taxonomy with the Canadian Pollination Initiative (CANPOLIN) at York University, Ontario. Since 2012, Cory has been a research scientist and Curator of Invertebrate Zoology at the Royal Saskatchewan Museum, Saskatchewan. His research continues to focus on bees: he has published on the taxonomy of Canadian/North American bees, the utility of DNA barcoding for bees, bee physiology, pollination contributions and diversity of the Canadian bee fauna.

Appendix 1. Threats assessment of the Macropis Cuckoo Bee (Epeoloides pilosulus) in Canada

The classification below is based on the IUCN-CMP (International Union for the Conservation of Nature–Conservation Measures Partnership) unified threats classification system. For a detailed description of the threat classification system, see the CMP web site (CMP 2010). Threats may be observed, inferred, or projected to occur in the near term. Threats are characterized here in terms of scope, severity, and timing. Threat “impact” is calculated from scope and severity. For information on how the values are assigned, see master et al. (2009) and footnotes to this table.

Scientific name: Macropis Cuckoo Bee (Epeoloides pilosulus)

Assessment date: September 9, 2023

Assessors: Cory Sheffield (report writer), John Klymko (Arthropods SSC Co-chair and facilitator), Jennifer Heron (Arthropods SSC Co-chair), Donna Hurlburt (NS), Robin Gutsell (AB), Jayme Lewthwaite (Arthropods SSC), Lisa Neame (AB), Syd Cannings (ECCC), Colin Jones (ON), Jason Gibbs (University of Manitoba), Sarah Vinge-Mazer (SK), Sarah Semmler (Arthropods SSC) and Joanna James (COSEWIC Secretariat).

References: Environment and Climate Change Canada. 2021. Recovery Strategy for the Macropis Cuckoo Bee (Epeoloides pilosulus) in Canada. Species at Risk Act Recovery Strategy Series. Environment and Climate Change Canada, Ottawa. vii + 12 pp.

Assigned overall threat impact: CD = Medium – Low

Impact adjustment reasons: Macropis Cuckoo Bee is wide-ranging and there is extensive unsurveyed potential habitat. Wetland habitat loss is extensive throughout areas with historical agricultural, urban, industrial, and other development, and climate change is ubiquitous. The host bee’s main food plant in Canada (Lysimachia terrestris) grows in ephemeral wet areas including meadows, fields, marshes, river and lakeshores and the edges of wetlands but also within drier areas. The other food plant, L. ciliata, grows in similar habitats. Threat impact was adjusted lower to consider the potential habitat and undocumented sites across the bee’s vast potential geographic range in Canada.

Overall, threat comments: See threats and limiting factors

^a Impact – The degree to which a species is observed, inferred, or suspected to be directly or indirectly threatened in the area of interest. The impact of each stress is based on Severity and Scope rating and considers only present and future threats. Threat impact reflects a reduction of a species population or decline/degradation of the area of an ecosystem. The median rate of population reduction or area decline for each combination of scope and severity corresponds to the following classes of threat impact: very high (75% declines), high (40%), medium (15%), and low (3%). Unknown: used when impact cannot be determined (for example, if values for either scope or severity are unknown).

^b Scope – Proportion of the species that can reasonably be expected to be affected by the threat within 10 years. Usually measured as a proportion of the species’ population in the area of interest. (Pervasive = 71 to 100%; Large = 31 to 70%; Restricted = 11 to 30%; Small = 1 to 10%)

^c Severity – Within the scope, the level of damage to the species from the threat that can reasonably be expected to be affected by the threat within a 10-year or three-generation timeframe. Usually measured as the degree of reduction of the species’ population (Extreme = 71 to 100%; Serious = 31 to 70%; Moderate = 11 to 30%; Slight = 1 to 10%).

^d Timing – High = continuing; Moderate = only in the future (could happen in the short term [< 10 years or 3 generations]) or now suspended (could come back in the short term); Low = only in the future (could happen in the long term) or now suspended (could come back in the long term); Insignificant/Negligible = only in the past and unlikely to return, or no direct effect but limiting.