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Osmia conjuncta Cresson, 1864


Scientific Name: Osmia conjuncta Cresson, 1864

Common Name: Osmia conjuncta


Osmia conjuncta Cresson, 1864: 31 [♀].

     Holotype ♀. USA, Connecticut, by E. Norton [ANSP no. 2552].

Osmia 4-dentata Cresson, 1878: 107 [♂]. Preoccupied, not Phyllotoma quadridentata Duméril, 1860 (nomen dubium)[1]. Synonymy by Robertson (1897: 347).

     Holotype ♂. USA, New York, by Comstock [ANSP no. 2551].

Osmia cressonii Dalla Torre, 1896. Replacement name for 4-dentata Cresson, 1878. Synonymy by Robertson (1897: 347).

Osmia quadridentata Dalla Torre, 1896: 392. Emended name for Osmia 4-dentata Cresson, 1878. Preoccupied, not Osmia quadridentata Fonscolombe, 1879 = Hoplitis (Anthocopa) jakovlevi (Radoszkowski, 1874) (as per Zanden 1996: 885). Synonymy by Cockerell (1912: 223).


Taxonomic Notes: Under his treatment of O. cressonii Dalla Torre, the replacement name for O. quadridentata Cresson proposed by Dalla Torre (1896: 392), Cockerell (1912: 219) indicated that Cresson’s taxon was preoccupied by Phyllotoma quadridentata Duméril, 1860 (which was treated as a tenative (i.e., “?”) synonym of Osmia quadridentata Fonscolombe, 1879 by Dalla Torre (1896: 406), though Cockerell (1912: 219) seemed to express concern on the validity of Duméril’s taxon. Sandhouse (1939: 139) did not include any Diceratosmia Robertson in her treatment of Osmia as it was considered a distinct genus, though she indicated that Osmia quadridentata Fonscolombe was the preoccupied name, not that of Duméril. Though not mentioned in his revision of Diceratosmia (i.e., Michener 1949: 260), Michener (1951: 1162) subsequently indicated that Osmia 4-dentata Cresson was preoccupied by Osmia quadridentata (Duméril) but subsequent authors (i.e., Mitchell 1962; Hurd 1979; Griswold and Rightmyer 2017) have indicated Osmia quadridentata Fonscolombe = Hoplitis (Anthocopa) jakovlevi (Radoszkowski, 1874), though that name would not pre-date Cresson’s O. 4-dentata. As suggested by Cockerell (1912), it seems best to consider Phyllotoma quadridentata Duméril, 1860 as nomen dubium.

DNA Barcode Index Number (BIN): BOLD:AAC0883, BOLD:AAC0882

Almost all specimens belong to BIN BOLD:AAC0883, with a single specimen assigned to BOLD:AAC0882; all are from Ontario, Canada.

Biology: This species is the only in Canada nesting exclusingly in snail shells (Rau 1937; Cane et al. 2007; Richards et al. 2011; Griswold and Rightmyer 2017; Onuferko et al. 2018; Fanaki et al. 2023). Rau (1937) and Fanaki et al. (2023) gave detailed accounts of nesting, the latter indicating that shells of exotic snails Cepaea spp. Held (Stylommatophora: Helicidae) were particurly abundant and utilized. It can be locally very abundant, especially in the Niagara region, but overall quite uncommon (Richards et al. 2011; Fanaki et al. 2023).

Distribution in Canada: Gibson 1916 [ON, QC, as O. quadridentata Cresson]; Mitchell 1962 [ON]; Richards et al. 2011 [ON]; Taylor 2014 [ON]; Normandin et al. 2017 [QC]; Griswold and Rightmyer 2017 [ON, QC]; Onuferko et al. 2018 [ON];  Fanaki et al. 2023 [ON].


[1] Other sources (i.e., Inventaire National du Patrimoine Naturel, 2023) also treat this as a synonym of Hoplitis (Anthocopa) jakovlevi (Radoszkowski, 1874), though this is not included in Ungricht et al. (2008) or Müller (2023).


Cresson ET (1878) Descriptions of new North American Hymenoptera in the collection of the American Entomological Society. Transactions of the American Entomological Society 7: 61-136.

Dalla Torre CG (1896) Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus. Volume X: Apidae (Anthophila). Engelmann, Leipzig, 644 pp.

Hurd PD (1979) Superfamily Apoidea. In: Krombein KV, Hurd Jr PD, Smith DR, Burks BD (Eds) Catalog of Hymenoptera in America North of Mexico. Smithsonian Institution Press, Washington, 2735 pp.

Mitchell TB (1962) Bees of the Eastern United States. Volume 2. North Carolina Agricultural Experimental Station Technical Bulletin 152, Raleigh, 557 pp.

Normandin É, Vereecken NJ, Buddle CM, Fournier V (2017) Taxonomic and functional trait diversity of wild bees in different urban settings. PeerJ 5: e3051.

Richards MH, Rutgers-Kelly A, Gibbs J, Vickruck JL, Rehan SM, Sheffield CS (2011) Bee diversity in naturalizing patches of Carolinian grasslands in southern Ontario, Canada. The Canadian Entomologist 143(3): 279-299.

Robertson C (1897) North American bees−descriptions and synonyms. Transactions of the Academy of Sciences of St. Louis 7: 315-356.

Michener CD (1951) Family Megachilidae. In: Muesebeck CF, Krombein KV, Townes HK (Eds) Hymenoptera of America north of Mexico Synoptic Catalog. 2. United States Department of Agriculture Agricultural Monograph, Washington. Pp. 1136-1186.

Sandhouse GA (1939) The North American bees of the genus Osmia (Hymenoptera: Apoidea). Memoirs of the Entomological Society of Washington 1: 1-167.

Cresson ET (1864) On the North American species of the genus Osmia. Proceedings of the Entomological Society of Philadelphia 3: 17-38.

Gibson A (1916) The entomological record, 1915. Annual Report of the Entomological Society of Ontario 46: 194-230.

Griswold T, Rightmyer MG (2017) A revision of the subgenus Osmia (Diceratosmia), with descriptions of four new species (Hymenoptera, Megachilidae). Zootaxa 4337(1): 1-37.

Michener CD (1949) A revision of the American species of Diceratosmia (Hymenoptera, Megachilidae). Annals of the Entomological Society of America 42, 258–264.

Cockerell TDA (1912) Names applied to bees of the genus Osmia, found in North America. Proceedings of the United States National Museum 42(1897): 215-225.

Zanden G van der (1996) Neue Arten und Synonyme bei paläarktischen Bauchsammlern (Hymenoptera aculeata, Apoidea, Megachilidae). Linzer Biologische Beiträge 28: 883-895.

Onuferko TM, Skandalis DA, Cordero RL, Richards MH (2018) Rapid initial recovery and long-term persistence of a bee community in a former landfill. Insect Conservation and Diversity 11: 88-99.

Rau P (1937) The life-history of Osmia lignaria and Osmia cordata, with notes on Osmia conjuncta. Annals of the Entomological Society of America 30(2): 324-343.

Cane JH, Griswold T, Parker FD (2007) Substrates and materials used for nesting by North American Osmia bees (Hymenoptera: Apiformes: Megachilidae). Annals of the Entomological Society of America 100: 350–358.[350:SAMUFN]2.0.CO;2

Fanaki IO, Irazuzta S, Dudley SA (2023) The native snail shell–nesting bee Osmia conjuncta (Hymenoptera: Megachilidae) exploits a local abundance of exotic Cepaea snails (Stylommatophora: Helicidae), choosing empty shells by size, colour, and microhabitat. The Canadian Entomologist 155: e22.

Sociality: Solitary
Nesting: Cavity Renter
Wintering Stage: Adult

Crop Preference: Not Available
Non Crop Preference: Not Available

Distribution: Ontario, Quebec
Ecozone: Mixwood Plains