The Bee Genera of Eastern Canada
Laurence Packer*, Julio A. Genaro** and Cory S. Sheffield***
York University, Department of Biology, 4700 Keele St., Toronto, ON, Canada, M3J 1P3
What are bees?
Canadian Bee Diversity
Bee Biology: Floral Relationships
Bee Biology: Nests
1. Ground: nests made by burrowing into the soil. Mason: nests made on a substrate from resin or mud. Cavities: nests made in naturally occurring cavities such as beetle borings in wood, snail shells, etc. Wood: nests excavated in woody substrates. Stems: nests excavated in pithy stems. Under rocks: (one species) brood cells made under rocks. Hive: the honey bee is the only species that nests in hives, although feral colonies can be found in other hollows and cavities. Rodent burrows: on the ground and in hollow trees; bumble bees nest in these diverse locations. Parasites: make no nests.
Bee Biology: Social Behaviour
1. Agapostemon. (Figs 132, 133). These bees are easily recognized through a combination of two features: bright green head and thorax with a pronounced carina around the posterior surface of the propodeum. The males are also the only bees that are bright green with yellow and black stripes on the metasoma. These are solitary or communal ground-nesting bees that are common in summer in southern regions of our area. Males in particular can often be found flying around Hollyhocks, Alcea spp., and Rose of Sharon, Hibiscus syriaca (both Mavlaceae), flowers in August and September. The four eastern species can be easily separated using Mitchell (1960), though A. radiatus (Say) is now known as A. sericeus (Foster).
2. Andrena. (Figs 134, 135, 136, 137). Andrenidae can be distinguished from other bee families by the paired subantennal sutures. Andrena in our area most commonly have three submarginal cells whereas the other andrenids (Calliopsis, Perdita, Protandrena) have two. Female Andrena can also be readily identified by the facial foveae that are covered in short velvety hairs; all other Canadian bees have hairless facial foveae or, more commonly, no facial foveae at all. These are common solitary ground-nesting bees ranging in size from 5mm to over 15mm, which construct nests in a wide variety of soil types and degrees of vegetation cover. Michener and Rettenmeyer (1956) remains the most detailed study of the nesting biology of any Andrena species. Most species have a black or dark brown integument (a few have red on the metasoma, males of quite a few have pale markings on the lower face). Variable in colour and density of pubescence, most species have dense, mostly brown hairs, while some have bright fuscous pubescence (e.g. A. milwaukeensis Graenicher), others more whitish hairs. Some are comparatively hairless, such as A. integra Smith. They are particularly common visiting willows (Salix, Salicaceae) in spring, but the genus as a whole can be found throughout the spring, summer and autumn. Late summer species are common on goldenrod (Solidago, Asteraceae). These bees can be found throughout eastern Canada, even in the warmer parts of the southern Arctic (Mitchell, 1960). There are approximately 74 species recorded from our area and they can be identified, albeit not easily, using Mitchell (1960), the Discover Life internet site, or using the keys of LaBerge (1967, 1969, 1971, 1973, 1977, 1980, 1986, 1987, 1989), LaBerge and Bouseman (1970), LaBerge and Ribble (1972, 1975), Donovan (1977), Bouseman and LaBerge (1978) and Ribble (1967, 1968).
3. Anthidiellum. (Fig 138). Along with Anthidium, Dianthidium and Paranthidium (discussed below), these bees are easily identified as yellow marked Megachilidae that possess a scopa. Our only species, A. notatum Latreille, which occurs in southern Ontario, can be distinguished from other non-cleptoparasitic Anthidiini by its small size, and the angulate anterior margin of the mesoscutum which overhangs the pronotum. Anthidiellum are summer bees which use resin to construct cells that are attached individually to stems.
4. Anthidium. (Figs 139, 140, 141). These are robust bees with yellow markings on the head and mesosoma, bands of yellow on the metasoma, and no arolia. One indigenous and two introduced Old World species occur in Ontario, one of these, A. manicatum (L.), was also recently reported from Nova Scotia (Hoebeke and Wheeler, 2005). These are the wool carder bees that line their brood cells with hairs from the leaves and stems of plants such as cultivated Lamb’s Ears (Stachys, Lamiaceae). Males are highly territorial and hover around the preferred floral hosts of the females, aggressively pursuing other individuals or other species of bee that visit the plants. Anthidium manicatum is very common in urban gardens in summer where they can be found at mint and other bluish-purple flowers with long corollas, even those kept in flower boxes on balconies of apartment buildings. The species can be distinguished using the keys of Miller et al. (2002) or Romankova (2003a).
5. Anthophora. (Figs 142, 143). These are robust long-tongued bees, with hairless forewing cells and with the outer region of the forewing papillate. Most species nest in the ground, but one, A. terminalis Cresson, excavates nests in pithy stems, and can be found commonly at tomato flowers in urban areas in southern Ontario. These are solitary species. Mitchell (1962) can be used to identify the eastern Canadian species, although A. plumipes (Pallas), a recently introduced European form, is not included in that work and may extend its range into eastern Canada. However, some of the species names in Mitchell (1962) are now considered subspecies or integrades of A. bomboides (Kirby) (see Brooks (1983) for clarification).
6. Apis. (Fig 144). Readily identified by lacking hind tibial spurs, but also by overall appearance, the well known domesticated honey bee, Apis mellifera L., is common throughout the warmer regions of Canada. This introduced species is the only bee in Canada to winter as a colony; all others have a solitary stage in their life history.
7. Augochlora. (Fig 145). These are bright green bees with an acute epistomal lobe. There is only one species of this genus in Canada, A. pura (Say), a bright bluish-green bee that nests solitarily in rotting wood. It can be found through much of the summer and is common in southern Ontario, less so in the Atlantic provinces.
8. Augochlorella. (Figs 146, 147). These are also bright green or bronze bees with a right-angled epistomal lobe, rounded tegula and lacking a carina surrounding the posterior surface of the propodeum. This genus also has only one species in eastern Canada, A. aurata (Smith)(previously known as A. striata (Provancher)). It is a greenish-bronze species, somewhat smaller than A. pura. This eusocial species (Mueller, 1997; Packer, 1990) nests in the ground, forming small turrets at the nest entrance. Augochlorella is common in southern parts of eastern Canada.
9. Augochloropsis. (Fig 148). A third genus of bright green bee with only one species occurs in our area. Augochloropsis metallica (Smith) is a bluish-green species, more robust than either of the preceding species. It can easily be identified by the shape of the tegula. It is a moderately common species in southern Ontario. This species is a ground-nester and it is probable that at least some nests contain multiple females.
10. Bombus. (Fig 149). The common and easily recognized bumble bees are large and furry corbiculate bees with no jugal lobe to the hind wing. All species are eusocial except for the subgenus Psithyrus, which are social parasites that invade host bumble bee nests and replace the queen’s ovipositional activities while relying on her workers to feed their offspring (Fisher, 1987). An additional species not of this subgenus, B. hyperboreus Schönherr, adopts a similar invasion strategy in the far north, but is not a social parasite further south (Richards, 1973). Bumble bees are found throughout our area, and occur even in the arctic where they can forage for 24 hours a day under conditions of continual sunlight. Identification of the 27 eastern species is comparatively easy and mostly based upon details of colouration (Laverty and Harder, 1988).
11. Calliopsis. (Figs 150, 151). The only species in eastern Canada, C. andreniformis Smith, is easily identified by the pattern of white markings on the face of the female and the entirely yellow legs of the male. These bees nest in flat, sandy soil and are locally abundant in suitable areas from southern Ontario to Cape Breton, Nova Scotia, in summer. The biology of this species was discussed in detail by Shinn (1967).
12. Ceratina. (Fig 152). The three species of small carpenter bees found in eastern Canada are all dark metallic blue with ivory markings on the face and/or legs. They nest in dead, pithy stems and, as they overwinter as adults, are among the few Canadian bees that can be collected in midwinter. Although males and females overwinter together, nests that are actively being provisioned house only a single adult female. These bees are active throughout the summer and are found throughout the southern regions of eastern Canada. Mitchell’s (1962) key works well for males, but female identification has recently been improved upon by Rehan et al. (in press), available on the Discover Life website.
13. Chelostoma. (Fig 153). Easily recognized as very narrow and cylindrical Megachilidae, as noted in the key. Three species are known from eastern Canada, two of them introduced from Europe and found in Ontario; the indigenous species, C. philadelphi (Robertson), is known from Ontario and Quebec. One of the introduced species, C. campanularum (Kirby),is a tiny, narrow black bee which commonly visits Campanula (Campanulaceae) flowers in urban areas. These are solitary bees that nest in stems. Buck et al. (2005) provide a key to the species in eastern Canada.
14. Coelioxys. (Figs 154, 155). In our area, these are black bees with bands and/or spots of short dense white hairs. The males have multiple spines at the end of the metasoma, whereas the females’ metasoma ends in a narrow point; these characteristics make this genus easy to recognize. They are found in summer throughout most of eastern Canada and are cleptoparasites that lay eggs in the nests of Megachile species. The ten eastern Canadian species can be identified using Mitchell (1962).
15. Colletes. (Figs156, 157). The S-shaped recurrent vein is diagnostic for this genus, as is the combination of a concave apex of the tongue and three submarginal cells. These bees have a densely pubescent head and mesosoma, usually orange-brown, sometimes dull brown, less commonly blackish or grey. The metasoma is entirely covered in hair in one rare species, C. solidaginis Swenk, but in other species is usually distinctly banded, with the bands at the apex of the terga. These are solitary bees that nest in the ground and line their tubular nests with a cellophane-like secretion that waterproofs the brood cells to prevent both waterlogging from rain and leakage of the rather watery provisions provided for the larvae (Torchio et al., 1988). Different species are active at different times of year such that the genus can be found from early spring (mostly on maple flowers, Acer) to late autumn (mostly on goldenrod, Solidago, Asteraceae). Colletes is common throughout eastern Canada. Romankova (2003b) keyed the Ontario species, but several additional ones have been discovered since, so Mitchell’s (1960) key remains useful for the approximately 17 species.
16. Dianthidium. (Fig 158). One species, D. simile (Cresson), occurs in Ontario.
17. Dufourea. (Fig 159). These are small brownish or black bees which have the antennal bases located low on the face, and a scopa which is most strongly developed on the hind tibia. There are three species in southern parts of eastern Canada, each is oligolectic on different plant species. The only moderately common species is D. novaeangliae (Robertson), which forages solely on pickerel weed (Pontederia, Pontederiaceae), an aquatic plant. As such, it is one of the few bees most easily collected while canoeing! The other two species have rarely been seen in our area. These are solitary, ground-nesting bees (Eickwort et al., 1986). Mitchell (1960) identifies the species easily enough.
18. Epeoloides. (Fig 160). This bee is easily identified as a long-tongued cleptoparasite (therefore lacking a scopa) that has no discrete patches or bands of appressed, pale coloured hairs. The one North American species, E. pilosula (Cresson), was thought to be extinct until rediscovered in Nova Scotia (Sheffield et al., 2004). Epeoloides attacks the nests of Macropis and flies in July, but is extremely rare.
19. Epeolus. (Fig 161). These are robust bees with bands and/or spots of white or creamy appressed hairs. The integument is black, sometimes marked with orange or red, especially on the legs. It is only likely to be confused with species of Triepeolus from which it can be separated by the short pseudopygidial area in females and posteriorly convergent margins of the pygidial plate in males. These are cleptoparasitic bees that attack Colletes, and they can often be found flying low over the ground looking for host nests. Mitchell (1962) keyed the 11 species in our area.
20. Halictus. (Fig 162). These are common ground-nesting bees easily identified as halictines by the strongly arched basal vein, strong apical wing venation, and apical hair bands on the metasomal terga. One species (H. confusus Smith) is dull metallic green, the other three are brownish-black. These are socially variable bees. Halictus rubicundus (Christ) is known to be solitary in shorter summer habitats and eusocial in warmer environments (Eickwort et al., 1996) and H. ligatus is one of the best studied social sweat bees (e.g. Richards et al., 1995). Halictus species can be found throughout eastern Canada except in the far north. The four species can be easily identified using Mitchell (1960).
21. Heriades. (Figs 163, 164). These are small, black, coarsely sculptured Megachilidae with a short horizontal portion of the propodeum that is made up of a single row of large pits. They fly in the summer and accept trap-nests. The biology of our most common species, H. carinata Cresson, which occurs as far east as Nova Scotia (Sheffield, 2006), was discussed by Matthews (1965). The three species in our area can be identified with Mitchell (1962).
22. Holcopasites. (Fig 165). The only species in our area, H. calliopsidis (Linsley), is easily identified as a small black and red bee with many spots of white, appressed hairs, giving a checkerboard appearance to the metasoma. It is a cleptoparasite that attacks the nests of Calliopsis andreniformis. It occurs as far east as Nova Scotia (Sheffield, 2006).
23. Hoplitis. (Fig 166). These are small to relatively large, black Megachilidae (a metallic green species occurs in western Canada), similar in appearance to black Osmia, but distinguishable by the elongate parapsidial line on the scutum, and the more elongate metasoma. These summer-flying bees are common throughout our area, some species ranging into the sub-arctic regions (Michener, 2000). Most species can be trap-nested in drilled wood blocks or hollow stems, but a recently recorded species (Buck et al., 2005), H. anthocopoides (Schenck) is a mason which constructs exposed nests out of small pebbles. The eight species in our area (excluding H. anthocopoides) are identifiable using Mitchell (1962).
24. Hylaeus. (Fig 167). Unlike most comparatively glabrous (hairless) species, Hylaeus are not cleptoparasites; rather, they carry pollen and nectar internally and therefore do not possess a scopa. Hylaeus are shiny black bees with white/yellow markings on the face (although females of one species, H. basalis (Smith), are completely black) and with pale banded legs. One species, H. nelumbonis (Robertson), has the basal few metasomal segments red. There are usually a few patches of white hairs on the mesosoma, and on the apicolateral portions of the more basal metasomal terga in some subgenera. Hylaeus are small bees common in the summer, and most nest in stems (and trap-nests) but a few species nest in the ground and, like Colletes, they line their nest with cellophane-like material. The best account of the nesting biology of any Hylaeus species is that of Torchio (1984). Hylaeus in our area can be identified using Mitchell (1960), although H. hyalinatus Smith, an introduced species, was only recently recorded in Ontario (Buck et al., 2005).
25. Lasioglossum. (Figs 168, 169). These are halictines with reduced apical wing venation. The numerous species are classified in four subgenera in eastern Canada: Lasioglossum, Evylaeus, Dialictus and Sphecodogastra. Most nest in the ground, although a few species of the subgenus Dialictus are known to nest in soft wood. This is the most socially diverse genus of bees in the world, with many solitary, a few communal and many eusocial species known. A few species are cleptoparasitic (previously placed in genus or subgenus Paralictus but now considered to be Dialictus – Fig 176). Lasioglossum are very common throughout temperate and boreal Canada, less so in the subarctic, and often make up a large proportion of all specimens collected in surveys (e.g. MacKay and Knerer, 1979; Grixti and Packer, 2006). Larger species (those of the subgenus Lasioglossum) are readily identified using McGinley (1986). The single Eastern Canadian species in the subgenus Sphecodogastra – L. oenotherae (Stevens) is found from Ontario to New Brunswick and is a common early morning visitor to the flowers of evening primroses and sundrops, Oenothera (Onagraceae) (Knerer and MacKay, 1969). The other subgenera, which are typically smaller bees (and many are dull metallic), can be identified, with some difficulty, using Mitchell (1960) although he raised several subgenera to generic rank, incorrectly associated the sexes of several species and made several other mistakes with this group. Ongoing molecular work reveals that there are numerous cryptic species in this difficult group.
26. Macropis. (Figs 170, 171). This is the only genus of Melittidae in Canada. These are uncommon, relatively small, ground-nesting bees that are completely dependent on their floral hosts, Lysimachia (Primulaceae), from which they collect pollen and oils. The oils are used both as a larval food source and as part of the nest cell lining (Cane et al., 1983). Macropis is found in the southern part of our area as far east as Nova Scotia. Mitchell (1960) can be used to separate our two species.
27. Megachile. (Figs 172, 173). The leafcutting bees are readily identified by the combination of metasomal sternal scopa, lack of arolia and lack of yellow integumental markings. All our species use cuttings from leaves or floral petals to line their brood cells which are usually in pre-existing holes in wood (they commonly accept trap-nests), although some species nest in the ground. One species, the alfalfa leafcutter bee, M. rotundata (Fabricius), was accidentally introduced into North America prior to the 1950’s, and is now managed for alfalfa pollination, although it visits many other flowers and has become widely established and is commonly collected. Megachile are common throughout eastern Canada as far north as the sub-arctic zone The 18 species can be identified using Mitchell (1962), although the key uses characteristics of the mandibles, primarily the teeth and cutting edge shape, and identification of specimens with closed mandibles or badly worn teeth, may be difficult.
28. Melissodes. (Figs 174, 175). These are robust, solitary ground-nesting, long-tongued bees. The males have extremely long antennae, in Eastern Canada shared only with Svastra obliqua (Say), which is much less common and rarely collected in our area. Melissodes can be separated by the narrowed anterior portion of the tegula. Mitchell (1962) can be used to separate the ten species in our area; M. rustica (Say) is now known as M. druriella (Kirby).
29. Nomada. (Figs 176, 177). Nomada are wasp-like bees with narrow bodies marked with yellow, orange or red (or combinations of these colours), lacking discrete hair patches and without a strongly curved basal vein. These are mostly cleptoparasites of Andrena and can be easily found flying low above the ground looking for host nests. They are found throughout our area to the arctic circle with different species active at different times of year, although they are most dominant in the early spring. Nomada are often difficult to identify, and numerous species are known from only one sex. Mitchell (1962) can be used to identify the 37 named species in our area and some taxa can be identified using the Discover Life website.
30. Osmia. (Figs 178, 179). These are robust bees, with a dull metallic blue-green integument in most species, a sternal metasomal scopa, and punctiform parapsidal lines. This is the only megachilid genus to overwinter as an adult, and they are thus common in spring and early summer throughout our area, north to the arctic circle. Some individuals in short summer climates skip a year entirely and fly almost two years after their mother laid the egg (Tepedino and Frohlich, 1984). They mostly nest in pre-formed cavities; holes in walls, door locks, and have even been found in stethoscopes in field hospitals! These species commonly accept trap nests. A few species, such as O. inermis (Zetterstedt), build nests under rocks. A variety of extraneous materials are used to line the brood cells, including grass blades, mud, chewed leaves, and gravel. Most of the 23 species can be identified using Mitchell (1962), although additional species have been recorded in our area since that time (Discover Life), and some species are notoriously difficult to identify (Rust, 1974).
31. Paranthidium. (Fig 180). The one uncommon species found in our area, P. jugatorium (Say), can readily be told from all other genera (except Anthidiellum, Anthidium and Dianthidium) by having a sternal scopa, yellow markings on the body, and from these three anthidiine genera by the presence of arolia, a rounded anterior profile to the mesoscutum, and the anterior portion of the mesopleuron which is not separated from the lateral surface by a sharp carina. It nests in sandy soil and lines the brood cells with resin (Evans, 1993).
32. Peponapis. (Fig 181). One species is known in the east, P. pruinosa (Say), the Hoary Squash Bee. This species is most easily identified through its host association: it is oligolectic on curcubits (Cucurbita, Curcubitaceae) and readily found in gardens in southern Ontario. This is a solitary ground-nesting bee found from mid to late summer. Information on this species from Ontario was presented by Kevan et al. (1989).
33. Perdita. (Fig 182). Perdita are small, rather flat bees with body mostly dull metallic and with pale markings on the face and metasoma. These are solitary or communal ground-nesting species and are locally common in southern parts of eastern Canada in the summer and autumn. The nesting biology of the three species found in eastern Canada was reviewed by Michener and Ordway (1963) and Eickwort (1977). The species can be identified using Mitchell (1960).
34. Protandrena. (Figs 183, 184). These are small, black bees with two subantennal sutures and glabrous facial foveae. Species in our area have two submarginal cells. Males have yellow face maculations, including the entire clypeus, though not as extensive as in Calliopsis. These are summer and autumn flying bees, which can often be collected on goldenrod (Solidago) and black-eyed susan (Rudbeckia, Asteraceae). Mitchell (1960) can be used to identify the six species in our area (as the genus Pseudopanurgus).
35. Sphecodes. (Fig 185). This is our only genus of cleptoparasitic halictines (strongly arched basal vein), which are also shiny, usually coarsely sculptured and with the metasoma largely red (but entirely black in males of a few species). These bees mostly attack the nests of other halictines. Common throughout our area south of the arctic circle. There are 24 species recorded from our area, and they can be identified with difficulty using Mitchell (1960). One reason for their taxonomic complexity is that species attacking a single eusocial host with strong size dimorphism between queens and workers, or a species attacking multiple hosts of different sizes, will exhibit marked size variation according to which caste or species of host the parasite female laid eggs on.
36. Stelis. (Figs 186, 187).Identifiable as cleptoparasitic Megachilidae with yellow markings on the metasoma. These bees attack Megachilidae, primarily Heriades and Hoplitis, but possibly Osmia and Chelostoma as well. The ten species can be identified using Mitchell (1962).
37. Svastra. (Figs 188, 189). One species is found in our area: S. obliqua (Say). It can be separated from other bees, except Melissodes, by the enormously long antennae in the male, and from Melissodes (and all other bees) by the spatulate hairs on some parts of the body (see the key for details). It is rare, known in eastern Canada only from southern Ontario and Quebec.
38. Triepeolus. (Fig 190). Readily identified from all other genera except Epeolus as a long-tongued cleptoparasitic bee with appressed patches/bands of white or yellowish hairs, giving a strongly patterned appearance. It is separated from Epeolus by the longer psuedopygidial area in females and sinuate lateral margin to the pygidial plate in males. These are cleptoparasites, mostly of Melissodes. Ten species are found in southern parts of eastern Canada. They can be identified using Mitchell (1962) or Rightmyer (2006).
39. Xylocopa. (Fig 191). One species is found in eastern Canada: Xylocopa virginica (L.). These large carpenter bees nest in wood and can be pests of outdoor wooden structures. Nest sharing by females is known and they are comparatively long-lived as adults. These bees are becoming increasingly common in southern Ontario and seem to be spreading north.
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