|A female cuckoo bee, Coelioxys sp. nectars on|
hairy false goldenaster, Heterotheca villosa in late fall
Coelioxys cuckoo bees are common in the summer months; in central Minnesota I typically see them from June until October. Both males and females can be observed visiting flowers for nectar and females looking for, or waiting to enter a host's nest. These cuckoo bees lay their eggs in the nests of leafcutter bees, Megachile spp. Less frequently, they have been documented laying eggs in the nests of Anthophora, Centris and Euglossa spp.
|A female cuckoo bee watches for the|
female leafcutter bee to exit the nest
in the rock cavity.
|The cuckoo bee flies closer to the entrance|
anticipating the exit of the host bee.
Females Coelioxys bees actively look for a host's nest. Once a nest is found, the female cuckoo bee waits until the host bee leaves the nest to collect provisions. With a short window of opportunity, the cuckoo bee slips in the empty nest and looks for a fully provisioned brood cell to lay its eggs in.
|The host leafcutter bee, Megachile sp. enters the nest in the|
rock cavity carrying a piece of leaf to line or cap the brood cell.
|The large sickle-like mandibles that the cuckoo bee larvae use to kill its siblings and host larva.|
Illustration from: Michener, C. D. (2000). The bees of the world (Vol. 1). JHU Press.
|A female cuckoo bee nectars on |
purple prairie clover, Dalea purpurea
|A female cuckoo bee perches on foliage low to the ground|
watching for a leafcutter bee to emerge from a nest in the ground.
Female: Tapered abdomen ending in an acute point
Male: Pronged or multi-spined abdomen
Both Male & Female: Hairs on the bottom of the eyes
Relatively hairless, dark gray - black, often pocked appearance
Many species have red legs
Native plants I have observed Coelioxys spp. foraging on:
Butterfly milkweed, Asclepias tuberosa
Wild Bergamot, Monarda fistulosa
Prairie Coreopsis, Coreopsis palmata
Hoary Vervain, Verbena stricta
Joe Pye Weed, Eutrochium maculatum Smooth Oxeye, Heliopsis helianthoides Black-Eyed Susan, Rudbeckia hirta
New England Aster, Symphyotrichum novae-angliae
Hairy False Goldenaster, Heterotheca villosa
Purple Prairie Clover, Dalea purpurea
Baker, J. R. (1971). Development and sexual dimorphism of larvae of the bee genus Coelioxys. Journal of the Kansas Entomological Society, 225-235.
Michener, C. D. (2000). The bees of the world (Vol. 1). JHU Press.
Rozen Jr, J. G., & Kamel, S. M. (2006). Interspecific variation in immature larvae of the cleptoparasitic bee genus Coelioxys (Hymenoptera: Megachilidae). Journal of the Kansas Entomological Society, 79(4), 348-358.
Scott, V. L., Kelley, S. T., & Strickler, K. (2000). Reproductive biology of two Coelioxys cleptoparasites in relation to their Megachile hosts (Hymenoptera: Megachilidae). Annals of the Entomological Society of America, 93(4), 941-948.