Longhorn Cactus Fly

Odontoloxozus longicornis maleOdontoloxozus longicornis male waiting for a mate on an oviposition substrate, a piece of rotting Opuntia.

Odontoloxozus longicornis males guarding a piece of rotting Opuntia. Male body size is highly variable in this species. Some males are about the same size as females, while others are more than twice as large. Large males stake out territories on suitable oviposition substrates, mate with a female, and may then guard her through multiple oviposition and mating bouts. Small males often linger in the periphery and sneak in to score a mating when the large, guarding male is distracted by a fight with another male or the arrival of a new female.

On the cracking surface of a rotting opuntia branch, a large male cactus fly (Odontoloxozus longicornis) is standing over two much smaller females who are ovipositing into a small crevice. Other males of varying sizes repeatedly approach the trio and are repelled by the guarding male. He briefly establishes genital contact with one of the females, and she resumes oviposition immediately after he withdraws his aedeagus. Tucson, Pima County, Arizona, USA. 16 November 2008. [taxonomy:binomial=Odontoloxozus longicornis]