ISSN 1911-2173

A product of the Biological Survey of Canada & the Entomological Society of Canada

Leafcutter and Mason Bees of the Genus Megachile Latreille (Hymenoptera: Megachilidae) in Canada and Alaska1

Leafcutter and Mason Bees of the Genus Megachile Latreille (Hymenoptera: Megachilidae) in Canada and Alaska1

Cory S. Sheffield*2

Claudia Ratti*

Laurence Packer*

Terry Griswold**

*Department of Biology, York University 4700 Keele St., Toronto, ON M3J 1P3 [email protected][email protected][email protected]. **USDA-ARS Bee Laboratory, Utah State Univ., Natural Resources Biology Bldg. Logan, UT 84322 [email protected].

1This paper is contribution #12 from the Canadian Pollination Initiative. 2Corresponding Author.

Abstract

Leafcutter and mason bees of the genus Megachile are common members of the North American bee fauna and many Megachile species are important pollinators of summer flowering crops and native plant species. Despite this, no comprehensive account of species in Canada and Alaska has been published. Our objective is to provide an up-to-date revision of the genus Megachile of this region, including an interactive key to the species, and summaries of biogeographic distribution and life history. Additionally, divergence in a 658 bp segment of the mitochondrial COI gene (the “DNA barcode” region) was used to clarify the taxonomic status of several Megachile species in North America. Based on morphological differences and over 6% sequence divergence in COI, M. (Litomegachileonobrychidis Cockerell, previously considered a subspecies of M. (Litomegachilebrevis Say, is recognized here as a valid species. Similarly, M. (Litomegachilepseudobrevis Mitchell, found in the southeastern United States, is also considered a distinct species and removed from synonymy with MbrevisMegachile (Eutricharaeaapicalis Spinola and M. (Megachiloidescasadae Cockerell and M. (Megachiloidesumatillensis (Mitchell) are recorded from Canada for the first time; M. (Xanthosarusgiliae Cockerell and M. (Megachilenivalis are placed into synonymy with M. (Xanthosaruscircumcincta (Kirby) and M. (Megachilelapponica Thomson, respectively, and are thus considered Holarctic in distribution; Msubanograe Mitchell is placed into synonymy with Msublaurita Mitchell (previously only known from its melanistic female form), and the male is described for the first time. Megachile (Megachiloidesalamosana Mitchell, known only from the male, M. (Megachiloideslaurita Mitchell, and M. (Megachiloideslaurita semilaurita Mitchell (both melanistic female forms) are placed into synonymy with M. (Megachiloidesanograe Cockerell, the latter three species previously only known only from the females. Full descriptions of all 38 species found in Canada and Alaska are provided.

A corrigendum to this paper has been published (November 27, 2020) doi:10.3752/cjai.2020.AC05

Megachile latimannus Photo by Stephen A. Marshall

Introduction

The Megachilidae is one of two families of long-tongued bees, the other being the Apidae (Michener 2007).  In North America, it is the only family in which females of non-cleptoparasitic taxa carry pollen entirely on the underside of the metasoma (Figure A).  Most megachilid bees have robust bodies with a head about as wide as the thorax, or wider (Banaszak & Romasenko 1998).  Megachilidae is found on every continent except Antarctica, and is one of the largest families in terms of the number of species (4037) and recognized genera (77) (Ascher & Pickering 2011; http://www.discoverlife.org; accessed May 16, 2011).  Species estimates in Michener (2007) are much lower (3198 in 77 genera).
The tribe Megachilini (Megachilinae) is represented in North America by two of the three genera; Megachile Latreille, the leafcutter bees,and their main cleptoparasite, Coelioxys Latreille; the third member, Radoszkowskiana Popov, is also a cleptoparasite of Megachile but is restricted to the Eastern Hemisphere (Rozen & Kamel 2007).  Megachile is one of the most common and diverse genera of bees (Mitchell 1980; O’Toole & Raw 1991; Michener et al. 1994; Baker & Engel 2006; Michener 2007).  Michener (2007) recognizes 56 extant subgenera; Engel & Baker (2006) describe an additional subgenus from Thailand known only from the male.  In the Western Hemisphere, 31 subgenera are known (Raw 2006), though Durante & Abrahamovich (2006) recognize Chaetochile Mitchell as a distinct monotypic subgenus and not a synonym of Dasymegachile Mitchell.  In North America, thirteen subgenera are indigenous, but species belonging to an additional three subgenera have been introduced (Cane 2003; Michener 2007), and also occur in Canada (Richards 1984; Magnum & Sumner 2003; Paiero & Buck 2003; Sheffield et al. 2010).  Hurd (in Krombein et al. 1979) listed 134 species of Megachile in America north of Mexico, including the genus Chalicodoma Lepeletier (recognized here as the subgenus Chelostomoides Robertson); an additional five species were reported by Michener et al. (1994).  A new North American species was described recently (Gonzalez & Griswold 2007).  However, taxonomic knowledge of the genus Megachile in North America remains far from complete as almost a third of the species are known from one sex only, primarily within the subgenus Megachiloides Mitchell (Sheffield & Westby 2007).  Interestingly, several species of Megachile that occur in Canada have been found as gynandromorphs, including M. angelarum Cockerell, M. gemula Cresson, M. latimanus Say, M. onobrychidis Cockerell, M. parallela Smith, M. perihirta Cockerell, and M. rotundata (Fabricius) (see Wcislo et al. 2004).

Biology of Megachile
Much is known about the biology of many leafcutter bees due to their importance in crop pollination (Hobbs & Lilly 1954; Pengelly 1955; Osgood 1974; Peterson et al. 1992; Richards 1993; Raw 2002) and the fact that many species accept trap-nests (Medler 1959, 1964; 1965; Fye 1965; Krombein 1967; Frolich & Parker 1983; O’Toole & Raw 1991; Sheffield et al. 2008).  Most species nest above ground in pre-existing cavities (Figure B) or excavate into pithy stems or decomposing wood (Stephen 1956; Ivanochko 1979).  Trap-nesting of bees has allowed detailed study of life-history, nest building, provisioning and egg laying behaviours (Medler 1959, 1964; Klostermeyer & Gerber 1969; Frolich & Parker 1983; Kim 1992 ), and documentation of incidences of cleptoparasitism (Scott et al. 2000; Sheffield et al. 2008).  Trap-nest surveys also allow association of males and females of the same species (Sheffield & Westby 2007).  However, several North American species within the subgenera Argyropile Mitchell, Litomegachile Mitchell, Megachiloides, and Xanthosarus Robertson are ground-nesters (Hobbs & Lilly 1954; Eickwort et al. 1981; Williams et al. 1986; Neff & Simpson 1991; Krombein & Norden 1995; Gordon 2000).  Table 1 summarizes nesting site information for species of Megachile in Canada and Alaska.
Leafcutter bees require suitable nesting sites (see Table 1), nest building materials, and sufficient/suitable food plants for nectar and pollen.  These three factors not only influence the diversity of bees within a given habitat by meeting their specific needs (i.e., pollen specialists), they also strongly affect the abundance and/or fecundity of certain species through the quantities at which they occur (Müller et al. 2006; Williams & Kremen 2007; Sheffield et al. 2008).  Hobbs & Lilly (1954) noted that nesting site availability dictated which species of Megachile were found within specific habitats in southern Alberta; the absence of trees and/or logs (i.e., nesting sites with pre-existing or easily excavated cavities) limited the number of cavity-nesting species, whereas ground-nesting species were more prevalent.  Leafcutters and other cavity-nesting bee species can often be encouraged to nest within natural and highly managed systems simply by placing trap-nests within these habitats (Sheffield et al. 2008).  Using artificial nesting material, M. rotundata, which nests gregariously within shelters, was developed as a commercial pollinator of alfalfa in western North America (Free 1993; Richards 1993).  Thus, seed production in this important industry owes much of its success to this species.
Cut leaf pieces are the main nesting material used by leafcutter bees for nest cell construction.  Hobbs & Lilly (1954) noted that ground-nesting leafcutter bees were common in the prairies within flying distance of leaf sources (e.g., shrubs, etc.), and declined greatly in open prairies without broad leaved plants.  However, not all Megachile in Canada use leaf pieces as nesting material; members of the subgenera Callomegachile (M. sculpturalis Smith) and Chelostomoides (M. angelarum and M. campanulae (Robertson)) are masons, and collect plant resins, pebbles and mud for cell partitioning and closure (Michener 2007), as does Megachile (Pseudomegachile) ericetorum Lepeletier (Banaszak & Romasenko 1998), a species only recently reported in North America (Sheffield et al. 2010). Megachile (Megachile) montivaga Cresson collects flower petals (Hobbs & Lilly 1954; Ivanochko 1979).
From a standpoint of encouraging leafcutter bees, all three of the requirements mentioned above can be found in most natural habitats.  Trap-nests can be provided to accommodate cavity nesting species, supporting increases in species richness and abundance in agricultural systems (Sheffield et al. 2008).  Although ground nesting Megachile species are also important alfalfa pollinators (Hobbs & Lilly 1954; Rank & Goerzen 1981), very few ground nesting bees have been developed for pollination (see Richards 1993).

Taxonomy
Many of the Megachile species in Canada and Alaska are common, though no comprehensive account has been published.  Mitchell (1962) published keys to the species found in eastern North America; his descriptions (Mitchell 1927; 1934) and subgeneric revisions (Mitchell 1935a, b, 1936, 1937a-d) cover most of the remaining species found in Canada.  Sheffield & Westby (2007) provided a review of the subgenus Megachile s. str. in the western Hemisphere, which included the previously undescribed male of M. nivalis Friese (considered here as a synonymy of M. lapponica Thomson).  Ivanochko (1979) provided the first comprehensive account of leafcutter bees in Canada, though he omitted the subgenus Chelostomoides (which was later covered by Snelling (1990)), and summarized their biology with respect to alfalfa pollinating potential, but remains unpublished and virtually unknown.
The purpose of this work is to provide a revision of the species of Megachile occurring in Canada and Alaska, including and interactive and web-based key.  The keys make use of morphological features, but molecular techniques (i.e., divergence levels in a 658 bp segment of the COI mitochondrial gene) have been used to verify male-female associations, and to clarify species designations.  A single middle leg was removed from pinned specimens; whenever possible multiple individuals of a species were analyzed to quantify the extent of intra-specific sequence divergence.  Specimens were primarily collected in Canada, but material was also obtained from several localities in North America.  DNA extracts were prepared following procedures outlined in Hajibabaei et al. (2005), and sequences or “DNA barcodes” will be published on BOLD (http://www.barcodinglife.org) in the “Bees of Canada” project.

Notes on using the key, and on identifying leafcutter bees

One of the main difficulties in identifying Megachile species, especially females, is that many keys are based on mandibular dentation.  In old individuals, mandibles are often so badly worn that the shape of the teeth and even their number are difficult to distinguish (Figure C).  A similar problem occurs when identifying dirty specimens or specimens with the mandibles closed.  Therefore, we have tried to provide a key in which dentition is not so heavily relied on, but for obvious reasons it remains a useful character for separating some species (and even some subgenera).  Colour images of female mandibles (Plate 1), male genitalia (Plate 2), lateral images of females and males (Plate 3) and distribution maps are provided for all species.  For difficult specimens (including those females in which mandibles are not visible or useful), users of the key are asked to read through the couplets fully and follow both alternatives within the dichotomy.  Full descriptions and diagnoses are also provided to facilitate accurate identification, and these should also be read for additional morphological characters and distribution information.  A standard format is used to facilitate quick comparison of specific characters; these are numbered consistently within descriptions of the head, mesosoma and metasoma.

Table 1.  Nesting biology summary of the genus Megachile in Canada and Alaska.

Species Nesting substrate Reference
M. addenda Sandy soil Medler & Lussenhop 1968; Ivanochko 1979; Cane et al. 1996
M. angelarum Cavities, trap-nests Barthell et al. 1998; Frankie et al. 1998
M. anograe Soil Hobbs & Lilly 1954; Bohart & Youssef 1972; Mitchell 1973
M. apicalis Cavities, trap-nests Barthell et al. 1998
M. brevis Cavities, hollow plant stems, soil, rolled leaves Hicks 1926; Michener 1953; Hobbs & Lilly 1954; Pengelly 1955; Ivanochko 1979; Baker et al. 1985; Packer 1987; Reed 1871
M. campanulae Cavities, trap-nests Medler 1966; Krombein 1967; Baker et al. 1985
M. casadae Unknown (probably soil)
M. centuncularis Cavities, trap-nests Krombein 1967; Sheffield et al. 2008
M. circumcincta Soil Latter 1906
M. coquilletti Cavities, trap-nests, probably soil? Bohart 1957; Barthell et al. 1998
M. dentitarsis Soil Hobbs & Lilly 1954; Bohart 1957
M. ericetorum Cavities, plant stems Banaszak & Romasenko 1998
M. fidelis Cavities, trap-nests Barthell et al. 1998; Frankie et al. 1998
M. fortis Soil Ivanochko 1979; Neff & Simpson 1991
M. frigida Rotting logs, trap-nests Hobbs & Lilly 1954; Pengelly 1955; Stephen 1956; Jenkins & Matthews 2004
M. gemula Poplar logs, hollow twigs Peck & Bolton 1946; Fye 1965; Medler & Lussenhop 1968
M. gentilis Cavities, trap-nests Snelling 2003; Kim 1992
M. inermis Cavities, trap-nests, rotting logs Stephen 1956; Medler 1958; Sheffield et al. 2008
M. lapponica Cavities, trap-nests Sheffield & Westby 2007
M. latimanus Soil Mitchell 1936; Bohart 1957; Ivanochko 1979
M. lippiae Probably soil Hicks 1926; Hobbs & Lilly 1954 (as M. cleomis)
M. manifesta Unknown (probably soil)
M. melanophaea Soil Hobbs & Lilly 1954; Pengelly 1955
M. mellitarsis Unknown
M. mendica Trap-nests; soil Medler 1965; Krombein 1967; Baker et al. 1985; Williams et al. 1986
M. montivaga Soil; old stems Ivanochko 1979; Hicks 1926; Hobbs & Lilly 1954; Baker et al. 1985
M. onobrychidis Probably soil and/or cavities? Bohart 1957
M. parallela Soil Fischer 1951; Hobbs & Lilly 1954
M. perihirta Soil Sladen 1918; Hicks 1926; Hobbs & Lilly 1954; Bohart 1957; Ivanochko 1979
M. pugnata Cavities, trap-nests, rotting logs Medler 1964; Hobbs & Lilly 1954; Sheffield et al. 2008
M. relativa Cavities, trap-nests Medler & Koerber 1958; Sheffield et al. 2008
M. rotundata Cavities, trap-nests, soil in vertical banks Krombein 1967; Sheffield et al. 2008
M. sculpturalis Cavities, trap nests, Xylocopa nests Mangum & Sumner 2003
M. sublaurita Soil Bohart & Youssef 1972
M. subnigra Unknown (probably soil)
M. texana Soil Krombein 1953; Hobbs & Lilly 1954; Eickwort et al. 1981
M. umatillensis Sandy soil Bohart & Youssef 1972
M. wheeleri Sandy soil, trap-nests at ground level Hobbs & Lilly 1954; Gordon 2000

Species Keys

Species

Megachile addenda
Megachile angelarum
Megachile anograe
Megachile apicalis
Megachile brevis
Megachile campanulae
Megachile casadae
Megachile centuncularis
Megachile circumcincta
Megachile coquilletti
Megachile dentitarsis
Megachile ericetorum
Megachile fidelis
Megachile fortis
Megachile frigida
Megachile gemula
Megachile gentilis
Megachile inermis
Megachile lapponica
Megachile latimanus
Megachile lippiae
Megachile manifesta
Megachile melanophaea
Megachile mellitarsis
Megachile mendica
Megachile montivaga
Megachile onobrychidis
Megachile parallela
Megachile perihirta
Megachile pugnata
Megachile relativa
Megachile rotundata
Megachile sculpturalis
Megachile sublaurita
Megachile subnigra
Megachile texana
Megachile umatillensis
Megachile wheeleri

Acknowledgments

We thank Sue Westby (retired), Agriculture and Agri- Food Canada, Kentville, NS; John Ascher, American Museum of Natural History, NY; Sam Droege, USGS Patuxent Wildlife Research Center, Beltsville, MD; Felix Sperling, University of Alberta, Edmonton, AB; Steve Marshall, University of Guelph, Guelph, ON; John Huber, Andy Bennett, and Louise Dumouchel, Canadian National Collection of Insects, Ottawa, ON; Elizabeth Elle, Simon Fraser University, Vancouver, BC for providing specimens for study. Thanks also to Roy Larimer, Visionary Digital, VA for advice and assistance with imaging, and to members of the Packer lab, York University, especially Lincoln Best and Nicholai de Silva, for providing additional specimens from Canadian locations, and Miriam Richards, Brock University, St. Catharines, ON for helpful comments on earlier drafts of the key. Additional thanks to Steve Marshall and Sheila Dumesh for use of photographs, and for encouragement and support throughout this study. DNA barcoding was funded by the Canadian Barcode of Life Network
from Genome Canada (through the Ontario Genomics Institute), NSERC (Natural Sciences and Engineering Research Council of Canada) and other sponsors listed at www.BOLNET.ca. Funding for CSS was provided by the NSERC-CANPOLIN Network.

References

Alfken, J.D. 1929. Apidae, excluding genus BombusIn: Entomologische Ergebnisse der schwedischen Kamtschatka-Expedition 1920-1922. Arkiv för Zoologi 20(A): 1-8.

Ascher, J.S., and J. Pickering 2011. Discover Life's bee species guide and world checklist. (http://www.discoverlife.org/mp/20q?guide=Apoidea_species&flags=HAS:)

Baker, D.B., and M.S. Engel. 2006. A new subgenus of Megachile from Borneo with arolia (Hymenoptera: Megachilidae). American Museum Novitates 3505: 1-12.

Baker, J.R., E.D. Kuhn, and S.B. Bambara. 1985. Nests and immature stages of leafcutter bees (Hymenoptera: Megachilidae). Journal of the Kansas Entomological Society 58: 290-313.

Banaszak, J., and L. Romasenko. 1998. Megachild Bees of Europe (Hymenoptera, Apoidea, Megachilidae). Pedagogical University of Bydgoszcz, Poland. 239 pp.

Barthell, J.F., G.W. Frankie, and R.W. Thorp. 1998. Invader effects in a community of
cavity nesting megachilid bees (Hymenoptera: Megachilidae). Environmental
Entomology 27: 240-247.

Benoist, R. 1940. Remarques sur quelques espèces de mégachiles principalement de la faune française. Annales de la Société Entomologique de France 109: 41-88.

Bohart, G.E. 1957. Pollination of alfalfa and red clover. Annual Review of Entomology 2: 355-380.

Bohart, G.E., and N.N. Youssef. 1972. Notes on the biology of Megachile (Megachiloides) umatillensis Mitchell (Hymenoptera: Megachilidae) and its parasites. Transactions of the Royal Entomological Society of London 124: 1-19.

Cane, J. H. 2003. Exotic nonsocial bees (Hymenoptera: Apiformes) in North America: ecological implications. Pgs. 113-126. In: K. Strickler, and J.H. Cane. (Eds). For Nonnative Crops, Whence Pollinators of the Future? Thomas Say Publications in
Entomology: Proceedings, Entomological Society of America. Lanham, MD.

Cane, J.H., D. Schiffhauer, and L.J. Kervin. 1996. Pollination, foraging, and nesting ecology of the leafcutting bee Megachile (Delomegachile) addenda (Hymenoptera: Megachilidae) on cranberry beds. Annals of the Entomological Society of America 89: 361-367.

Cockerell, T.D.A. 1898. Some bees of the genus Megachile from New Mexico and Colorado. Annals and Magazine of Natural History (7) 1: 125-130.

Cockerell, T.D.A. 1898. New and little known bees from Washington State. Proceedings of the Academy of Natural Sciences of Philadelphia 50: 50-56.

Cockerell, T.D.A. 1899. Notes on American bees. Entomologist 32: 154-159.

Cockerell, T.D.A. 1900. The New Mexico bees of the genus Megachile and a new AndrenaAnnals and Magazine of Natural History (7) 6: 7-20.

Cockerell, 1902. Hymenoptera of southern California I. Bulletin of the Southern California Academy of Sciences 1: 70-71.

Cockerell, T.D.A. 1904. Some bees from San Miguel County, New Mexico. Entomologist 37: 5-9.

Cockerell, T.D.A. 1904. Two new bees. Entomological News 15: 32-34.

Cockerell, T.D.A. 1906a. Descriptions and records of bees—VIII. Annals and Magazine of Natural History (7) 17: 222-2230.

Cockerell, T.D.A. 1906b. The bees of Florissant, Colorado. Bulletin of the American Museum of Natural History 22: 419-455.

Cockerell, T.D.A. 1908a. Descriptions and records of bees—XVIII. Annals and Magazine of Natural History (8) 1: 259-267.

Cockerell, T. D. A. 1908b. A new name in MegachileCanadian Entomologist 40: 460.

Cockerell, T.D.A. 1912. Canadian bees in the British Museum. Canadian Entomologist 44: 354-358.

Cockerell, T. D. A., 1913. Descriptions and records of bees—LII. Annals and Magazine of Natural History (8) 11: 530-542.

Cockerell, T. D. A., 1914. Descriptions and records of bees—LVIII. Annals and Magazine of Natural History (8) 13: 424-433.

Cockerell, T.D.A. 1915. Descriptions and records of bees—LXVI. Annals and Magazine of Natural History (8) 15: 341-350.

Cockerell, T.D.A. 1916. Descriptions and records of bees—LXXI. Annals and Magazine of Natural History (8) 17: 277-287.

Cockerell, T.D.A. 1924. Descriptions and records of bees—C. Annals and Magazine of Natural History 9 (13): 594-606.

Cockerell, T.D.A. 1925. Bees in the collection of the California Academy of Sciences. Proceedings of the California Academy of Sciences (4) 14: 185-215.

Cockerell, T.D.A. 1928. Bees collected in Siberia in 1927. Annals and Magazine of Natural History (10) 1: 345-361.

Cockerell, T.D.A. 1930. Siberian bees. Entomologist 63: 184.

Cockerell, T.D.A. 1931. Descriptions and records of bees—CXXVI. Annals and Magazine of Natural History (10) 7: 273-281.

Cooper, K W. 1984. Discovery of first resident population of the European bee, Megachile apicalis, in the United States (Hymenoptera: Megachilidae). Entomological News 95: 225-226.

Costa, A. 1863. Nuovi studii sulla entomologia della Calabria ulteriore. Atti dell’Accademia nazionale di scienze fisiche e matematiche di Napoli 1(2): 1–80.

Cresson, E.T. 1872. Hymenoptera Texana. Transactions of the American Entomological Society 4: 153-292.

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.

Cresson, E.T. 1879. Descriptions of new North American Hymenoptera in the collection of the American Entomological Society. Transactions of the American Entomological Society 7:201-214.

Dalla Torre, C.G. de 1896. Catalogus Hymenopterorum Vol. X, Apidae (Anthophilia). Leipzig, Engelmann, 643 pp.

Dours, J.A. (1873) Hyménoptères du bassin mediterranéen Andrena (suite). Biareolina, Eucera. Revue et Magazin de Zoologie 3: 274–325.

Dufour, L. 1841. Recherches anatomiques et physiologiques sur les Orthoptères, les Hyménoptères et les Néuroptères. Deuxieme partie. Mémoires de l'Académie des Sciences de l'Institut de France 7: 265-647 (Part II: 374-556).

Durante, S.P., and A.H. Abrahamovich. 2006. Redescription of Chaetochile as a subgenus of Megachile (Hymenoptera, Megachilidae). Transactions of the American Entomological Society 132: 103-109.

Eickwort, G.C., R.W. Matthews, and J. Carpenter. 1981. Observations on the nesting behavior of Megachile rubi and M. texana with a discussion of the significance of soil nesting in the evolution of megachilid bees (Hymenoptera: Megachilidae). Journal of the Kansas Entomological Society 54: 557-570.

Engel, M.S., and D.B. Baker. 2006. A remarkable new leaf-cutter bee from Thailand. Beitrage zur Entomologie 56: 69–74.

Fabricius, J.Ch. 1787. Mantissa Insectorum sistens eorum species nuper detectas adiectis characteribus genericis, differentiis, specificis, emendationibus. Hafniae (Proft) 1. 20 + 348 pp.

Fabricius, J.Ch. 1793. Entomologia systematica emendata et aucta, secundum classes, ordines, genera, species adjectis synonymis, locis, observationibus, descriptionibus. Hafniae (Proft), 2, 8 + 519 p.

Ferton, C. 1914. Perezia maura, nouveau genre d’Apiares parasites d’Algérie et observations de ce genre. Annales de la Société Entomologique de France 83: 233-237.

Fischer, R.L. 1951. Observations on the nesting habits of megachilid bees. Journal of the Kansas Entomological Society 24: 46-50.

Fischer, R.L. 1956. The muscular mechanism of the male metasoma and genitalia of Megachile fortis Cresson (Hymenoptera: Megachilidae). Canadian Entomologist 88: 657-673.

Frankie , G.W., R.W. Thorp, L.E. Newstrom-Lyoyd, M.A. Rizzardi, J.F. Barthell, T.L. Griswold, J.-Y. Kim, and S.

Kappagoda. 1998. Monitoring solitary bees in modified wildland habitats: implications for bee ecology and conservation. Environmental Entomology 27: 1137-1148.

Free, J.B. 1993. Insect Pollination of Crops. Second Edition. Academic Press, Inc. San Diego, CA. 684 pp.

Friese, H. 1903. Neue Arten der Bienen gattung Megachile aus Amerika. Zeitschrift für Systematische Hymenopterologie und Dipterologie 3(4): 246-248.

Frohlich, D.R., and F.D. Parker. 1983. Nest building behavior and development of the sunflower leafcutter bee: Eumegachile (Sayapis) pugnata (Say) (Hymenoptera: Megachilidae). Psyche 90: 193-209.

Fye, R.E. 1965. Biology of Apoidea taken in trap nests in northwestern Ontario (Hymenoptera). Canadian Entomologist 97: 863-877.

Gerstaecker, C.E.A. 1869. Beiträge zur näheren Kenntnis einiger Bienen-Gattungen. Entomologische Zeitung 30: 315-367.

Gibbs, J., and C.S. Sheffield. 2009. Rapid range expansion of the Wool-Carder Bee, Anthidium manicatum (Linnaeus) (Hymenoptera: Megachilidae), in North America. Journal of the Kansas Entomological Society 82: 21-29.

Gonzalez, V.H., and T.L. Griswold. 2007. A review of the North and Central American Megachile subgenus Argyropile Mitchell (Hymenoptera: Megachildae). Zootaxa 1461: 1-14.

Gordon, D.M. 2000. Plants as indicators of leafcutter bee (Hymenoptera: Megachilidae) nest habitats in coastal dunes. Pan-Pacific Entomologist 76: 219-233.

Hajibabaei, M., J.R. deWaard, N.V. Ivanova, S. Ratnasingham, R.T. Dooh, S.L. Kirk, P.M. Mackie, and P.D.N. Hebert. 2005. Critical factors for assembling a high volume of DNA barcodes. Philosophical Transactions of the Royal Society B: Biological Sciences 360: 1959-1967.

Hall, H.G., and J.S. Ascher. 2011. Surveys of bees (Hymenoptera: Apoidea: Anthophila) in natural areas of Alachua County in North-Central Florida. Florida Entomologist 93: 609-629.

Hinojosa-Díaz, I.A., O. Yáñez-Ordóñez, G. Chen, A.T. Peterson, and M.S Engel. 2005. The North American invasion of the giant resin bee (Hymenoptera: Megachilidae). Journal of Hymenoptera Research 14: 69-77.

Hirashima, Y. and Y. Maeta. 1974. Bees of the genus Megachile sensu lato (Hymenoptera, Megachilidae) of Hokkaido and Tohoku District of Japan. Kontyu 42: 157-173.

Hobbs, G.A. 1957. Alfalfa and red clover as sources of nectar and pollen for honey, bumble, and leaf-cutter Bees (Hymenoptera: Apoidea). Canadian Entomologist 89:230-235.

Hobbs, G.A., and C.E. Lilly. 1954. Ecology of species of Megachile Latreille in the
mixed prairie region of southern Alberta with special reference to pollination of
alfalfa. Ecology 35: 453-462.

Hobbs, G.A., W. O. Nummi, J. F. Virostek. 1961. Food-gathering behaviour of honey, bumble, and leaf-cutter bees (Hymenoptera: Apoidea) in Alberta. Canadian Entomologist 93: 409-419.

Hurd, P.D., Jr., 1979. Superfamily Apoidea. Pgs. 1741-2209. In: 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, DC.

Ivanochko, M. 1979. Taxonomy, Biology and Alfalfa Pollinating Potential of Canadian Leaf-Cutting Bees: Genus Megachile Latreille (Hymenoptera: Megachilidae). M.Sc. Thesis, McGill University, Montreal, QC.

Javorek, S.K. 1996. The Potential of the Alfalfa Leafcutter Bee Megachile rotundata Fabr. (Hymenoptera: Megachilidae) as a Pollinator of Lowbush Blueberry (Vaccinium angustifolium Ait., V. myrtilloides Michx.). M.Sc Thesis, Acadia University, Wolfville, NS.

Jenkins, D.A., and R.W. Matthews. 2004. Cavity-nesting hymenoptera in disturbed habitats of Georgia and South Carolina: nest architecture and seasonal occurrence. Journal of the Kansas Entomological Society 77: 203-214.

Kim, J.-K. 1992. Nest dimensions of two leaf-cutter beees (Hymenoptera: Megachilidae). Annals of the Entomological Society of America 85: 85-90.

Kirby, W. 1802. Monographia Apum Angliae. II. Ipswich, 388 pp.

Klostermeyer, E.C., and H.S. Gerber. 1969. Nesting behavior of Megachile rotundata (Hymenoptera: Megachilidae) monitored with an event recorder. Annals of the Entomological Society of America 62: 1321-1325.

Krombein, K.V. 1953. A note on the nesting habits of Megachile texana Cresson. Proceedings of the Entomological Society of Washington 55: 84-85.

Krombein, K.V. 1967. Trap-nesting Wasps and Bees: Life Histories, Nests, and Associates. Smithsonian Press, Washington, DC. vi + 570 pp.

Krombein, K.V., and B.B. Norden. 1995. Notes on the behavior and taxonomy of Megachile (Xeromegachile) brimleyi Mitchell and its probable cleptoparasite, Coelioxys (Xerocoelioxys) galactiae Mitchell (Hymenoptera: Megachilidae). Proceedings of the Entomological Society of Washington 97: 86-89.

Krunic, M. D. 1971. Influence of food on the cold-hardiness of Megachile rotundata (F.). Canadian Journal of Zoology 49:863–865.

Krunic, M. D., and R. W. Salt. 1971. Seasonal changes in glycerol content and supercooling points of Megachile rotundata (F.) and M. relativa Cress. Canadian Journal of Zoology 49:663–666.

Latter, O.H. 1906. How do inquiline bees find the nest of their host? Nature 74: 200.

Lepeletier, A.L.M. 1841. Histoire naturelle des Insectes. Hyménoptères. Vol. 2. Librairie Encyclopédique de Roret, Paris. 680 pp.

Linnaeus, C. 1758. Systema naturae per regna tria naturae secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. T. I. Edition X. Holmia. 823 pp.

Lovell, J.H, and T.D.A Cockerell. 1907. The Megachilidae of Southern Maine. Psyche 14: 15-21.

Magnum W.A., and R.W. Brooks. 1997. First records of Megachile (Callomegachile) sculpturalis Smith (Hymenoptera: Megachilidae) in the continental United States. Journal of the Kansas Entomological Society 70: 146-148.

Magnum, W.A., and S. Sumner. 2003. A survey of the North American range of Megachile (Callomegachile) sculpturalis, and adventive species in North America. Journal of the Kansas Entomological Society 76: 658-662.

Mavromoustakis, G.A. 1953. On the bees (Hymenoptera, Apoidea) of Cyprus. Part IV. Annals and Magazine of Natural History (12)6: 769-781.

Medler, J.T. 1959. A note on Megachile centuncularis (Linn.) In Wisconsin (Hymenoptera: Megachilidae). Canadian Entomologist 91: 113-115.

Medler, J.T. 1964. A note on Megachile (Sayapis) pugnata pugnata Say in trap-nests in
Wisconsin (Hymenoptera: Megachilidae). Canadian Entomologist 96: 918-921.

Medler, J.T. 1965. A note on Megachile mendica Cresson in trap nests in Wisconsin (Hymenoptera: Megachilidae). Proceedings of the Entomological Society of Washington 67: 113-116.

Medler, J.T. 1966. A resin bee using trap-nests in Wisconsin and a note on other resin bees (Hymenoptera: Megachilidae). Entomological News 77:228-230.

Medler, J.T., and T.W. Koerber. 1958. Biology of Megachile relativa Cresson in trap-nests in Wisconsin. Annals of the Entomological Society of America 51: 337-344.

Medler, J.T., and J.F. Lussenhop. 1968. Leaf-cutter bees of Wisconsin (Hymenoptera: Megachilidae). University of Wisconsin Research Bulletin 274: 1-80.

Michener, C.D. 1947. Bees of a limited area in southern Mississippi (Hymenoptera; Apoidea). American Midland Naturalist 38: 443-455.

Michener, C.D. 1953. The biology of a leafcutter bee (Megachile brevis) and its associates. University of Kansas Science Bulletin 35: 1659-1748.

Michener, C.D. 1962. Observations on the classification of the bees commonly placed in the genus Megachile (Hymenoptera: Apoidea). Journal of the New York Entomological Society 70: 17-29.

Michener, C. D. 2007. The Bees of the World. 2nd Ed. Johns Hopkins University Press, Baltimore, MD. xvi+[1]+953 pp.

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.  vii + 209 pp.

Mitchell, T. B. 1924. New megachilid bees. Journal of the Elisha Mitchell Scientific Society 40: 154-165.

Mitchell, T.B. 1926. New species of Megachile, with notes and corrections (Hymenoptera). Transactions of the American Entomological Society 52: 111-118.

Mitchell, T. B. 1927. New megachilid bees. Psyche 34: 104-121

Mitchell, T.B. 1934. A revision of the genus Megachile in the Nearctic region. Part I. Classification and descriptions of new species (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 59: 295-361; plates xx-xxi.

Mitchell, T.B. 1935a. A revision of the genus Megachile in the Nearctic region. Part II. Morphology of the male sternites and genital armature and the taxonomy of the subgenera Litomegachile, Neomegachile and CressoniellaTransactions of the
American Entomological Society 61: 1-44; plate i.

Mitchell, T.B. 1935b. A revision of the genus Megachile in the Nearctic region. Part III. Taxonomy of the subgenera Anthemois and Delomegachile (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 61: 155-205; plates viii-ix.

Mitchell, T.B. 1936. A revision of the genus Megachile in the Nearctic region. Part IV. Taxonomy of the subgenera Xanthosarus, Phaenosarus, Megachiloides and Derotropis (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 62: 117-166; plates viii-xi.

Mitchell, T.B. 1937a. A revision of the genus Megachile in the Nearctic region. Part VI. Taxonomy of subgenera Argyropile, Leptorachis, Pseudocentron, Acentron and Melanosarus (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 63: 45-83; plates v-vi.

Mitchell, T.B. 1937b. A revision of the genus Megachile in the Nearctic region. Part VII. Taxonomy of the subgenus Sayapis (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 63: 174-206; plates xii-xiii.

Mitchell, T.B. 1937c. A revision of the genus Megachile in the Nearctic region. Part V. Taxonomy of the subgenus Xeromegachile (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 62: 323-382; plates xxii-xxvi.

Mitchell, T.B. 1937d. A revision of the genus Megachile in the Nearctic region. Part VIII. Taxonomy of the subgenus Chelostomoides, addenda and index (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 63: 381-421; plates xxvi-xxix.

Mitchell, T.B. 1943. Records and descriptions in the megachilid subgenus Argyropile (Hymenoptera, Megachilidae). Pan-Pacific Entomologist 19: 12-16.

Mitchell, T.B. 1962. Bees of the eastern United States. Volume II. North Carolina Agricultural Experiment Station Technical Bulletin 152. 557 pp.

Mitchell, T.B. 1973. A Subgeneric Revision of the Bees of the Genus Coelioxys of the Western Hemisphere. Contribution from the Department of Entomology, North Carolina State University; Raleigh, NC. iii + 129 pp.

Mitchell, T.B. 1980. A Generic Revision of the Megachiline Bees of the Western Hemisphere. Contribution from the Department of Entomology, North Carolina State University; Raleigh, NC. ii + 95 pp.

Müller, A., Diener, S., Schnyder, S., Stutz, K., Sedivy, C. and Dorn, S. 2006. Quantitative pollen requirements of solitary bees: implications for bee conservation and the evolution of bee-flower relationships. Biological Conservation 130: 604-615.

Neff, J.L. and B.B. Simpson. 1991. Nest biology and mating behavior of Megachile fortis in Central Texas (Hymenoptera: Megachilidae). Journal of the Kansas Entomological Society 64: 324-336.

Nurse, C. G. 1903. New species of Indian aculeate Hymenoptera. Annals and Magazine of Natural History (7) 11: 529-549.

Nylander, W. 1852. Reviso synoptica apum  borealium, comparatis speciebus Europae mediae. Notiser ur Sällskapets pro Fauna et Flora Fennica Förhandlingar 2: 225-348.

Osgood, C.E. 1974. Relocation of nesting populations of Megachile rotundata, an important pollinator of alfalfa. Journal of Apicultural Research 13: 67-73.

O'Toole, C. and A. Raw. 1991. Bees of the World. Blandford. London, UK. 192 pp.

Packer, L. 1987. The triungulin larva of Nemognatha (Pauronemognatha) punctulata LeConte (Coleoptera: Meloidae) with a description of the nest of its host – Megachile brevis pseudobrevis Say (Hymenoptera: Megachilidae). Journal of the Kansas Entomological Society 60: 280-287.

Paiero, S.M. and M. Buck. 2003. The giant resin bee, Megachile sculpturalis Smith, and other newly introduced and newly recorded native Megachilidae and Andrenidae (Apoidea) from Ontario. Journal of the Entomolgical Society of Ontario 134: 141-143.

Panzer, G.W.F. 1798. Faunae Insectorum Germanicae. H. 49–60. Nürnberg : Felssecker.

Parker, F.D., and G.E. Bohart 1979. Dolichostelis, a new genus of parasitic bees (Hymenoptera: Megachilidae). Journal of the Kansas Entomological Society 52: 138-153.

Parker, F.D., and D.R. Frohlich. 1983. Hybrid sunflower pollination by a manageable composite specialist: the Sunflower Leafcutter Bee (Hymenoptera: Megachilidae). Environmental Entomologist 12: 576-581.

Peck, O., and J.L. Bolton. 1946. Alfalfa seed production in northern Saskatchewan as affected by bees, with a report on means of increasing the populations of native bees. Scientific Agriculture 26: 388-418.

Pengelly, D.H. 1955. The biology of bees of the genus Megachile with special reference to their importance in alfalfa seed production in southern Ontario. Ph.D. Thesis, Cornell University; Ithaca, NY.

Pérez, J. 1902. Espèces nouvelles de mellifères paléarctiques. Procès-verbaux de la Société Linnéenne de Bordeaux 57: 119-122.

Perkins, R. C. L. 1899. Hymenoptera Aculeata [except ants], pp. 1-115, pls. I, II, in R. C. L. Perkins and A. Forel, Hymenoptera Aculeata, in D. Sharp, ed., Fauna Hawaiiensis Volume 1, pt. 1. London: Cambridge University Press.

Peterson, S.S., C. R. Baird, and R.M. Bitner. 1992. Current status of the alfalfa leafcutter
bee, Megachile rotundata, as a pollinator of alfalfa seed. Bee Science 2: 135-142.

Pitts-Singer, T.L., and J.H. Cane. 2011. The Alfalfa Leafcutting Bee, Megachile rotundata: the world’s most intensively managed solitary bee. Annual Review of Entomology 56: 221-237.

Provancher, L. 1882. Faune Canadienne. Les Insectes Hyménoptères. Naturaliste Canadien 13: 225-242.

Provancher, L. 1883. Petite faune entomologique du Canada et particulierement de la province de Quebec. Quatrieme Ordre, les Hymenopteres. C. Darveau, Quebec. 830 pp.

Provancher, L. 1888. In 1885-1889. Additions et Corrections au Volume II de la Faune Entomologique du Canada Traitant des Hyménoptères, pp. 1-475. Quebec: Darveau.

Rank, G.H., and D.W. Goerzen. 1981. Native leafcutter bee species and associated parasites in commercial hives in Saskatchewan, Canada. Apidologie 12: 211-220.

Raw, A. 2002. New combinations and synonymies of leafcutter and mason bees of the Americas (Megachile, Hymenoptera, Megachilidae). Zootaxa 71: 1-43.

Raw, A. 2006. A new subgenus and three new species of leafcutter bees, Megachile (Austrosarus) (Hymenoptera, Megachilidae) from central Brazil. Zootaxa 1228: 25-34.

Reed, E.B. 1871. Notes on Megachile brevis, Say. Canadian Entomologist 3: 210-211.

Richards, K.W. 1984. Alfalfa leafcutter bee management in western Canada. Agriculture Canada Publication 1495E. 53 pp.

Richards, K.W. 1993. Non-Apis bees as crop pollinators. Revue suisse de Zoologie 100: 807-822.

Robertson, C. 1895. Notes on bees, with descriptions of new species. Transactions of the American Entomological Society 22: 115-125.

Robertson, C. 1903. Synopsis of Megachilidae and Bombinae. Transactions of the American Entomological Society 29: 163-178.

Rozen, J.G, Jr., and S.M. Kamel. 2007. Investigations on the biologies and immature stages of the cleptoparasitic bee genera Radoszkowskiana and Coelioxys and their Megachile hosts (Hymenoptera: Apoidea: Megachilidae: Megachilini). American Museum Novitates 3573: 1-43.

Say, T. 1823. A description of some new species of Hymenopterous Insects. Western Quarterly Report 2: 71-82.

Say, T. 1837. Descriptions of new species of North American Hymenoptera, and observations on some already described. Boston Journal of Natural History 1: 361-416.

Schrottky, C. 1902. Ensaio sôbre abelhas solitárias do Brazil. Revista do Museu Paulista 5: 330–613, pls. XII-XIV.

Scott, V.L., S.T. Kelley, and K. Strickler. 2000. Reproductive biology of two Coelioxys cleptoparasites in relation to their Megachile hosts (Hymenoptera: Megachilidae). Annals of the Entomological Society of America 93: 941-948.

Scott, V.L., J.S. Ascher, T. Griswold, and C.R. Nufio. The bees of Colorado (Hymenoptera: Apoidea: Anthophila). Natural History Inventory of Colorado (in press).

Sheffield, C.S. 2006. Diversity and Management of Bees for the Pollination of Apple in the Annapolis Valley of Nova Scotia. Ph.D. Thesis, University of Guelph, Guelph, ON.

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., and S.M. Westby. 2007. The male of Megachile nivalis Friese, with an updated key to members of the subgenus Megachile s. str. (Hymenoptera: Megachilidae) in North America. Journal of Hymenoptera Research 16: 178-191.

Sheffield, C. S., P. G. Kevan, S. M. Westby, and R. F. Smith. 2008. Diversity of cavity-nesting bees (Hymenoptera: Apoidea) within apple orchards and wild habitats in the Annapolis Valley, Nova Scotia, Canada. Canadian Entomologist 140: 235-249.

Sheffield, C.S., M. Richards, and T. Griswold. 2010. Discovery of the Old World bee, Megachile (Pseudomegachile) ericetorum (Hymenoptera: Megachilidae), in Ontario, Canada. Journal of the Entomological Society of Ontario 141: 85-92.

Sladen, F.W.L. 1918. Pollination of alfalfa by bees of the genus Megachile. Agricultural Gazette of Canada 5: 125-126.

Sladen, F.W.L. 1919. Further notes on the latimanus group of the bee genus Megachile. Canadian Entomologist 51: 85.

Smith, F. 1844. Descriptions of the British species of leaf-cutter bees (Megachile of authors); with observations on their economy. Zoologist 2: 689-697.

Smith, F. 1853. Catalogue of Hymenopterous Insects in the Collection of the British Museum. Part I. Andrenidae and Apidae. London. 197 pp.

Smith, F. 1879. Descriptions of New Species of Hymenoptera in the Collection of the British Museum. London. xxi + 240 pp.

Snelling, R.R. 1990. A review of the native North American bees of the genus Chalicodoma (Hymenoptera: Megachilidae). Contributions in Science, Natural History Museum of Los Angeles County 421: 1-39.

Spinola, M. 1808. Insectorum Liguriae Species Novae aut Rariores. 2: 1-262.

Strand, E. 1915. Apidae von Tsingtau. Entomologische Mitteilungen 4: 69-75.

Strand, Ε. 1917. Ueber einige Apiden des deutschen Entomologischen Museums. Archiv für Naturgeschichte 83A (11): 58-68.

Stephen, W.P. 1956. Notes on the biologies of Megachde frigida Smith and M. inermis Provancher (Hymenoptera: Megachilidae). Pan-Pacific Entomologist 32: 95-101.

Tepedino, V.J., and D.R. Frohlich. 1982. Mortality factors, pollen utilization, and sex ratio in Megachile pugnata Say (Hymenoptera: Megachilidae), a candidate for commercial sunflower pollination. Journal of the New York Entomological Society 90: 269-274.

Thomson, C.G. 1872. Skandinaviens Hymenoptera. Lund, 2: 1–286.

Titus, E.S.G. 1906. Some notes on the Provancher Megachilidae. Proceedings of the Entomological Society of Washington 7: 149-165.

Tkalců, B. 1977. Taxonomisches zu einigen paläarktischen Bienenarten (Hymenoptera: Apoidea). Vestník Ceskoslovenské Spolecnosti Zoologické 41: 223-239.

Tkalců, B. 1988. Neue paläarktische Arten und Unterarten der Gattungen Chalicodoma und Megachile (Hymenoptera, Apoidea, Megachilidae). Vestník Ceskoslovenské Spolecnosti Zoologické 52: 48-62.

Trostle, G., and P.F. Torchio. 1994. Comparative nesting behavior and immature development of Megachile rotundata (Fabricius) and Megachile apicalis Spinola (Hymenoptera: Megachilidae). Journal of the Kansas Entomological Society 67: 53-72.

van der Zanden, G. 1989. Neue oder wenig bekannte Arten und Unterarten der paläarktischen Megachiliden (Insecta, Hymenoptera, Apoidea, Megachilinae). Entomologische Abhandlungen Staatliches Museum für Tierkunde in Dresden 53(6): 71-86.

Viereck, H.L. 1902. Descriptions of North American bees. Canadian Entomologist 34: 325-331-

Viereck, H.L. 1916. The Hymenoptera, or wasp-like insects of Connecticut. Connecticut State Geological and Natural History Survey Bulletin 22: 1-824, pls. I-X.

Wcislo, W.T., V.H. Gonzalez, and L. Arneson. 2004. A review of deviant phenotypes in bees in relation to brood parasitism, and a gynadromorph of Megalopta genalis (Hymenoptera: Halictidae). Journal of Natural History 38: 1443-1457.

Williams, N.M., and C. Kremen. 2007. Resource distributions among habitats determine solitary bee offspring production in a mosiac landscape. Ecological Applications 17: 910-921.

Williams, H.J., M.R. Strand, G.W. Elzen, S.B. Vinson, and S.J. Merritt. 1986. Nesting behavior, nest architecture, and use of Dufour's gland lipids in nest provisioning by Megachile integra and M. mendica mendica (Hymenoptera: Megachilidae). Journal of the Kansas Entomological Society 59: 588-597.

Wu, Y. 2006. Hymenoptera Megachilidae. Fauna Sinica, Insecta 44: 1-474.

Zayed, A., S.A. Constantin, and L. Packer. 2007. Successful biological invasion despite a severe genetic load. PLoS One 2(9): e868. doi: 10.1371/journal.pone.0000868.

Cite

Sheffield, C.S., Ratti, C., Packer, L., Griswold, T. 2011. Leafcutter and Mason Bees of the Genus Megachilidae Latreille (Hymenoptera: Megachilidae) in Canada and Alaska. Canadian Journal of Arthropod Identification No. 18, 29 November 2011, available online at doi: 10.3752/cjai.2011.18

Looking for something?

Scroll to…