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.