Scientific Name: Dioxys pomonae pomonae Cockerell, 1910
Common Name: Dioxys pomonae
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].
Dioxys pomonae timberlakei Hurd, 1958: 285 [♀, ♂] [valid subspecies].
Holotype ♀. USA, California, San Bernardino County, Kramer Hills, 25 April 1957, by P.D. Hurd, Jr., on Gilia davyi [CAS no. 6669].
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.
Only D. pomonae pomonae Cockerell has been recorded from Canada (Sheffield and Heron 2019: 69).
Dioxys 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) provide a detailed account of its behaviour.. Rozen and Favreau (1967) studied the biology of this species in relation to its attack strategy on its host, Osmia nigrobarbata, and illustrated a larval stage. Rozen (1967) described immature stages of the several members of the genus, including D. pomonae.
Cockerell TDA (1910) Some new American bees. The Canadian Entomologist 42(5): 169-171. https://doi.org/10.4039/Ent42169-5
Cockerell TDA (1911) New and little known bees. Transactions of the American Entomological Society 37(3): 217-241. https://www.jstor.org/stable/25076889
Cockerell TDA (1916a) XXX.—Descriptions and records of bees—LXXI. Annals and Magazine of Natural History (8) 17: 277-287. https://doi.org/10.1080/00222931608693784
Cockerell TDA (1938) XV.—Descriptions and Records of Bees.—CLXIX. Annals and Magazine of Natural History, Series 11 2(8): 146-154. https://doi.org/10.1080/03745481.1938.9755447
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 (!966) 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.
Nesting: Cavity Renter
Pollen Specialization: Not Applicable
Wintering Stage: Variable
Distribution: British Columbia
Ecozone: Western Interior Basin