Reprinted with permission from: Mitchell, T.B. 1962 Bees of the Eastern United States. North Carolina Agricultural Experiment Station Technical Bulletin No. 152.
FEMALE—Length 8-9 mm.; black including legs, the tegulae more brownish-testaceous, spurs yellow; eyes very slightly convergent below; clypeal margin nearly straight, with
very shallow and rather short, incurved, or emarginate area on each side of center; mandibles 4-dentate, a bevelled edge between 3rd and 4th teeth, where the margin is very slightly angulate; lateral ocelli subequ ally distant from eyes and margin of vertex; cheeks slightly narrower than eyes; punctures of vertex fine and close but quite deep and distinct, becoming somewhat more shallow and obscure on cheeks, irregularly so below; face below ocelli densely rugose, supraclypeal area closely and rather coarsely punctate on each side, with some shining, impunctate spaces apically in center, clypeus with a very narrow, obscure, shining and sparsely punctate median line, punctures on each side rather coarse and densely crowded; pubescence yellowish-white, rather short on face and cheeks, rather dense around antennae and on face laterally, thin, erect and rather elongate on vertex, hairs yellowish or dark; pubescence of cheeks more whitish, short above, somewhat more elongatebelow; thorax short, white pubescent laterally and posteriorly, quite densely so around tuberdes and behind wing bases, more yellowish, very short and inconspicuous on scutum, scutellum with more elongate, erect, yellowish hairs; dorsum of thorax densely punctate throughout, punctures rather coarse in center, punctures of pleura somewhat shallower but contiguous, becoming somewhat finer and crowded above; lateral faces of pleura somewhat shining, very minutely and quite closely punctate, posterior face somewhat more shin-
ing, punctures irregular, minute and vague; all basitarsi shorter and somewhat narrower than their tibiae; tegulae with only a few, scattered, minute and obscure punctures; wings subhyaline, veins piceous; abdominal terga 2 and 3 very shallowly grooved across base, these not carinate, apical margins of 2-5 rather abruptly depressed laterally but not medially, with entire, whitish, apical fasciae that are quite dense laterally, narrow medially; tergum 1 with rather copious but thin, elongate, whitish pubeseence that is rather dense laterally, 2-4 with very short, fuscous, discal pubescence, 3-6 with conspicuous, black hairs evident on each side in dorsal view; punctures fine and close on the more basal terga, disc of 2 with a dull, sublateral, impunctate area; punctures of 3-5 quite deep, distinct, and well separated; tergum 5 quite similar to 4, 6 nearly straight in profile, with numerous, suberect, fuscous hairs evident, without pale tomentum, surface very finely and quite densely punctate; scopa entirely pale on sterna 2-4, pale basally but more or less black apically and laterally on 5, entirely black on 6; the more basal sterna very closely and rather finely punctate, punctures becoming somewhat more coarse and sparse on the more apical sterna, apical margins narrowly depressed, distinctly white fasciate.
MALE—Length 7-8 mm.; black, tegulae somewhat more brownish or testaccous, front tarsi in part yellowish, spurs yellow; eyes very slightly convergent below; median third of clypeal margin very slightly incurved; mandibles 3-dentate, inferior process sub-basal, slender and acute; apical segment of flagellum slender and simple; lateral ocelli subequally distant from eyes and margin of vertex; cheeks considerably narrower than eyes; vertex rather dull, punctures very close, rather fine but deep and distinct, these becoming somewhat finer and more shallow on cheeks; face below ocelli rather finely rugoso-punctate, clypeus very finely and densely rugose; pubescence of face and vertex yellow, dense around antennae and over lower portion of face, supraclypeal area with very dense, subappressed, upwardly directed hairs that completely hide surface, clypeal pubescence more erect, slightly downcurved at tips, but largely obscuring surface, that on vertex thin and erect, yellowish on cheeks above, becoming white, very long and dense below; pubescence of thorax more whitish, quite dense laterally and posteriorly, yellowish or whitish on dorsum, more elongate and erect on scutellum; dorsum of thorax dull, surface densely and finely rugoso-punctate, punctures of pleura somewhat coarser but densely crowded; lateral faces of propodeum rather smooth, with only exceedingly minute, vague punctures, posterior face somewhat more shining, with minute, vague and sparse punctures; front coxal spines spatulate, rather broad and quite short, densely white pubescent posteriorly, coxae rather densely white pubescent laterally but largely bare toward inner side, no red bristles evident; front tarsi slender and simple, with a very short but rather dense, posterior fringe, segments 2 and 3 yellow at base, 4 and 5 largely yellow; front tibiae dark, and front femora largely dark on posterior face, apical half of anterior face quite conspicuously yellow, lower margin only obscurely carinate and yellow not invading margin of posterior face; mid tibial spurs well developed, mid and hind tarsi slender and simple; tegulae minutely and closely punctate; wings subhyaline, somewhat clouded apically, veins piceous; basal grooves of abdominal terga very shallow, subcarinate, apical margins of 2-5 rather deeply depressed laterally but not medially, with dense, complete, whitish or yellowish fasciae; basal tergum with copious, erect, entirely pale pubescence, becoming very dense laterally, disc of 2 rather densely covered with suberect, pale hairs which do not hide surface, 3 and 4 with shorter, more obscure, suberect pubescence which is dark at least in part; punctures of terga close medially, fine on 2 and somewhat coarser on 3 and 4, discs of 2 and 3 with dull sublateral, impunctate areas on each side; tergum 5 densely pale tomentose across base, with sub-erect, somewhat darker hairs apicaliy, apical margin deeply depressed laterally but not in center, punctures rather irregular but quite coarse and close, apical margin not fasciate; tergum 6 very densely pale tomentose, largely hiding surface, carina very low and irregularly crenulate, median emargination very obscure, apical margin without distinct median teeth, and lateral angles very obscure; tergum 7 transverse, flattened, not at all produced medially; sterna 1-4 exposed, finely and rather closely punctate, punctures becoming very fine apically on 4, 2 and 3 quite deeply depressed apically, yellowishhyaline, with quite dense fringes of rather elongate, white hairs; sternum 5 quite broadly incurved apically, median area occupied by the very short, transverse setose area, the setae very fine and dense; setose areas of sternum 6 slightly separated medially, setae very fine and quite dense, apical lobe broad and very short, deeply incurved medially, resulting in a pair of sublateral, more or less acute lobes; gonocoxites of genital armature strongly narrowed above base, strongly and rather obliquely compressed, down-curved apically, but tip elongate, very narrow, at right angles to the sub-apical part, inner surface of apical half very conspicuously long setose.
DISTRIBUTION—This is another Old World species, and was introduced into the United States aarentIy some time during
just after World War II. It now ranges from Virginia to Massachusetts, west to California, and is in flight during June, July and August.
FLOWER RECORDS—Asclepias, Melilotus, Polygonum, Solidago and Veronica.
There is a degree of uncertainty regarding the identity of this species. A female specimen in the Copenhagen Museum that
indicated as the type is in close agreement with centuncularis Linnaeus, and bears little resemblance to the species which has been accepted by European taxonomists as rotundata. There is a possibility that this concept of rotundata is based on another type specimen. Moreover, the original brief description seems to suggest this species rather than centuncularis.
Extracted from: Sheffield C. S., et al (2011). Leaf cutter and Mason Bees of the Genus Megachile Latreille (Hymenoptera; Megachilidae) in Canada and Alaska. Canadian Journal of Arthropod Identification No. 18 Megachile (Eutricharaea) rotundata (Fabricius, 1793)
Apis rotundata Fabricius, 1793. Entom. system. 2: 332 (♂).
Apis pacifica Panzer, 1798. Faunae Ins. German. 55: 16 (♀).
Megachile imbecilla Gerstaecker, 1869. Stettin. Entomol. Ztg. 30: 359 (♀).
Diagnosis: The female of M. rotundata can be recognized by the combination of dense, white apical fasciae on the metasomal sterna (i.e., beneath the scopa), the dull, impunctate fovea-like patches laterally on T2, a nearly straight clypeal margin, and the scopa entirely pale on S4 with some pale hairs basally on S5. It is most similar to M. apicalis. Females of M. apicalis have the apical edge of clypeus angulate medially, and the scopa black apically and laterally on S4, and entirely so on S5 and S6. The male of M. rotundata is recognized by the dull, lateral, impunctate areas on T2 only, and tarsomeres 4 and 5 largely yellow. They are most similar to M. apicalis. Males of M. apicalis have dull, lateral, impunctate areas on both T2 and T3, and mostly dark tarsomeres (which may be yellowish basally).
FEMALE: Length 8-9 mm.
Head. 1) compound eyes very slightly convergent below; lateral ocelli subequally distant from eyes and margin of vertex, 2) clypeal margin nearly straight, with very shallow and rather short emarginate area on each side of the central impunctate edge, 3) mandibles 4-dentate, with cutting edge between 3rd and 4th teeth, margin of 4th tooth very slightly angulate (Plate 1, Figure M6), 4) gena narrower than compound eye (4:7), 5) punctures of vertex fine and close but quite deep and distinct, becoming somewhat more shallow and obscure on gena,irregularly so below; frons densely rugose, supraclypeal area closely and rather coarsely punctate on each side, with some shining, impunctate spaces apically in centre, clypeus with a very narrow, obscure, shining and sparsely punctate median line, punctures on each side rather coarse and densely crowded, 6) pubescence yellowish-white, rather short on face, rather dense around antennae and on paraocular area, sparse, erect and rather elongate on vertex, with dark hairs intermixed; pubescence of gena more whitish, short above, somewhat more elongate below, 7) F1 and F2 quadrate and subequal in length, slightly shorter than pedicel, which is longer than broad (2:1.5), remaining flagellomeres slightly longer, but almost quadrate, apical flagellomere longer than broad (5:3).
Mesosoma. 1) pubescence short, white laterally and posteriorly, quite dense around pronotal lobes and behind wing bases, more yellowish, very short and inconspicuous on mesoscutum, scutellum with more elongate, erect, yellowish hairs, 2) dorsal surface densely punctate throughout, punctures rather coarse in centre, lateral faces of pleura somewhat shining, with punctures somewhat shallower but contiguous, becoming somewhat finer and crowded above, larger and sparser below, propodeum somewhat more shining, punctures irregular, minute and vague, triangle dull and impunctate, becoming somewhat rugose basally, 3) all basitarsi shorter and somewhat narrower than their tibiae, spurs yellow, 4) tegula brownish-black with only a few, scattered, minute and obscure punctures, 5) wings subhyaline, veins black.
Metasoma. 1) disc of T2 with a dull, sublateral, impunctate area, fovea-like, distinct from remaining surface of disc; T2-T5 with apical margins rather abruptly depressed laterally but not medially, with entire, whitish, apical fasciae that are quite dense laterally, narrow medially; T1 with rather copious but sparse, elongate, whitish pubescence that becomes rather dense laterally, T2-T4 with very short, black, discal pubescence, T2-T6 with conspicuous, black hairs evident on each side in dorsal view, T6 nearly straight in profile, with numerous, suberect, black hairs evident on disc, without pale tomentum; punctures fine and close on the more basal terga, punctures of T3-T5 quite deep, distinct, and well separated; T6 surface very finely and quite densely punctate, 2) scopa entirely pale on S2-S4, S5 with scopal hairs pale basally, but more or less black apically and laterally, entirely black on S6; the more basal sterna very closely and rather finely punctate, punctures becoming somewhat more coarse and sparse on the more apical sterna; apical margins narrowly depressed, distinctly white fasciate beneath scopa.
MALE: Length 6-8 mm.
Head. 1) compound eyes convergent below; lateral ocelli subequally distant from eyes and margin of vertex, 2) median third of clypeal margin slightly incurved, 3) mandibles 3-dentate, lower process slender and acute, subbasal in position, 4) gena considerably narrower than compound eye (3:4), 5) punctures of vertex very close, rather fine but deep and distinct, these becoming somewhat finer and more shallow on gena; face below ocelli rather finely rugosopunctate, clypeus very finely and densely rugose, 6) pubescence of face and vertex yellow, dense around antennae and over lower portion of face, supraclypeal area with very dense, subappressed, upwardly directed hairs that completely hide surface, clypeal pubescence more erect, slightly down curved at tips, but largely obscuring surface, that on vertex sparse and erect, yellowish on gena above, becoming white, very long and dense below, 7) F1 about as long as broad, and subequal in length to pedicel, remaining flagellomeres longer than broad (5:3), apical flagellomere slender and elongate (7:3).
Mesosoma. 1) pubescence whitish, quite dense laterally and posteriorly, yellowish or whitish on mesoscutum, more elongate and erect on scutellum, 2) dorsal surface dull, surface densely and finely rugosopunctate, punctures of pleura somewhat coarser but densely crowded; propodeum rather smooth, with only exceedingly minute, sparse punctures, triangle dull and impunctate, 3) front coxal spine spatulate, rather broad and quite short, densely white pubescent posteriorly, coxa rather densely white pubescent laterally but largely bare toward inner side, no red bristles evident; front tarsus slender and simple, with a very short but rather dense, posterior fringe, tarsomeres 2 and 3 yellow at base, 4 and 5 largely yellow; front tibia dark, and front femur largely dark on posterior face, apical half of anterior face quite conspicuously yellow, lower margin only obscurely carinate and yellow not invading margin of posterior face; mid tibial spur well developed, mid and hind tarsi slender and simple, spurs yellow, 4) tegula brownish-black, minutely and closely punctate, 5) wings subhyaline, somewhat clouded apically, veins black.
Metasoma. 1) disc of T2 with dull sublateral, impunctate areas; basal grooves of T3 and T4 very shallow, subcarinate with a basal fasciae arising from under the edge of the carina; apical margins of T2-T5 rather deeply depressed laterally but not medially, with dense, complete, whitish or yellowish fasciae; T1 with copious, erect, entirely pale pubescence, becoming very dense laterally, disc of T2 rather densely covered with suberect, pale hairs that do not hide surface, T3 and T4 with shorter,more obscure, suberect pubescence, which is dark at least in part; punctures of terga close medially, fine on T2 and somewhat coarser on T3 and T4, T5 densely pale tomentose across base, with suberect, somewhat darker hairs apically, apical margin deeply depressed laterally but not in centre, punctures rather irregular but quite coarse and close, apical margin not fasciate; T6 very densely pale tomentose, largely hiding surface, carina very low and irregularly crenulate, median emargination very obscure, apical margin without distinct median teeth, and lateral angles very obscure; T7 transverse, flattened, not at all produced medially, 2) S1-S4 exposed, finely and rather closely punctate, punctures becoming very fine apically on S4, S2 and S3 quite deeply depressed apically, yellowish hyaline, with quite dense fringes of rather elongate, white hairs.
Genitalia. Plate 2, Figure G6.
Discussion. Although its presence in the Maritime Provinces may be a result of its ongoing commercial release for pollination of lowbush blueberry (Javorek 1996; see Sheffield 2008), trap-nest surveys in NS (Sheffield et al. 2008) have recovered M. rotundata in areas outside of the range of this crop. Therefore, it may have established naturally or from previous introductions in the province prior to the 1990’s. Its cold-hardiness probably limits its natural distribution in Canada (Krunic 1971; Krunic and Salt 1971; Sheffield 2008), and distributional records in more northern areas are probably a reflection of where it has been released for agricultural purposes: alfalfa pollination in the west and lowbush blueberry in the east. This species is a cavity nester, and accepts trap nests (Table 1). Pitts-Singer and Cane (2011) provide a comprehensive review of the management history of this important commercial pollinator; Trostle and Torchio (1994) discussed its nesting behaviour and development.
Distribution. Introduced into Atlantic Canada as a pollinator of lowbush blueberry, established populations in NS, and from southern QC-BC (see Map 6). Also used in NL, though not established.
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