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Dioxys pomonae pomonae Cockerell, 1910


Scientific Name: Dioxys pomonae pomonae Cockerell, 1910

Common Name: Pomona Dioxys


Dioxys pomonae Cockerell, 1910: 169 [♂].

     Holotype ♂. USA, California, Claremont, by C.F. Baker [USNM no. 23245].

Dioxys phaceliae Cockerell, 1911: 235 [♀]. Synonymy of D. pomonae pomonae Cockerell by Hurd (1958: 283).

     Holotype ♀. USA, New Mexico, Albuquerque, April, by J.R. Watson, on Phacelia corrugata [CAS no. 15643].

Dioxys catalinensis Cockerell, 1938: 148 [♂]. Synonymy of D. pomonae pomonae Cockerell by Hurd (1958: 283).

     Holotype ♂. USA, California, Santa Catalina Island, Pebbly Beach [CAS no. 15642].


Taxonomic notes: The synonymies made by Hurd (1958: 283) were based on the type specimens showing only small amounts of variation in integument and pubescence colouration, and based on comparison to the sex assiociations made by Cockerell (1916: 285). At that time, these taxa were known only from the type materials.

DNA Barcode Index Number (BIN): BOLD:AAE0346

BiologyDioxys are parasites in the nests of other megachilid bees, including Anthidium (Newberry 1900; Jaycox 1966), and Osmia (Rozen and Favreau 1967). Hurd (1958) listed Anthidium collectum Huard, Megachile subexilis Cockerell, and Osmia pellax Sandhouse as hosts. Rozen and Favreau (1967) studied the biology of this species in relation to its attack strategy on Osmia nigrobarbata and illustrated a larval stage. Rozen (1967) described immature stages of the several members of the genus, including D. pomonae.

Distribution in Canada: Sheffield and Heron 2019 [BC].

Only D. pomonae pomonae Cockerell has been recorded from Canada (Sheffield and Heron 2019: 69). Horning (1966) gave an account of three species in the Pacific Northwest, though none of these reached Canada.


Cockerell TDA (1916) Descriptions and records of bees.—LXXI. Annals and Magazine of Natural History, Series 8 17(100): 277-287.

Cockerell TDA (1910) Some new American bees. The Canadian Entomologist 42(5): 169-171.

Cockerell TDA (1911) New and little known bees. Transactions of the American Entomological Society 37(3): 217-241.

Cockerell TDA (1938) Descriptions and Records of Bees.—CLXIX. Annals and Magazine of Natural History, Series 11 2(8): 146-154.

Hurd PD (1958) American bees of the genus Dioxys Lepeletier and Serville (Hymenoptera: Megachilidae). University of California Publications in Entomology 14: 275-302.

Jaycox ER (1966) Observations of Dioxys productus productus (Cresson) as a parasite of Anthidium utahense Swenk (Hymenoptera: Megachilidae). The Pan-Pacific Entomologist 42: 18-20.

Newberry M (1900) Notes on the nesting of Anthidium paroselae Ckll. Psyche 9: 94.

Rozen JG (1967) The immature instars of the cleptoparasitic genus Dioxys (Hymenoptera: Megachilidae). Journal of the New York Entomological Society 75(4): 236-248.

Rozen JG, Favreau MS (1967) Biological notes on Dioxys pomonae pomonae and on its host, Osmia nigrobarbata (Hymenoptera: Megachilidae). Journal of the New York Entomological Society 75(4): 197-203.

Sheffield CS, Heron JM (2019) The bees of British Columbia (Hymenoptera: Apoidea, Apiformes). Journal of the Entomological Society of British Columbia 115: 44-85.

Horning DS (1966) Distribution records for the genus Dioxys in the Pacific Northwest (Hymenoptera: Megachilidae). Proceedings of the Entomological Society of Washington 68(2): 157.

Sociality: Parasitic
Nesting: Cavity Renter
Pollen Specialization: Not Applicable
Wintering Stage: Variable

Crop Preference: Not Available
Non Crop Preference: Helianthus sp., Phacelia sp., Cryptantha sp., Gilia sp.

Distribution: British Columbia
Ecozone: Western Interior Basin

Distribution Map