Behavioral traits and sexual recognition: multiple signaling in the reproductive behavior of Cyclocephala distincta (Melolonthidae, Cyclocephalini)

Abstract

Night-foraging cyclocephaline scarab beetles rely on fl oral structures of specifi c plant hosts for food and shelter, as well as mating sites. Although the role of fl oral fragrances as long-range attractants in these interactions has been elucidated, the mechanisms that mediate close-range mate discrimination in aggregations are still unclear. We recorded the mating-oriented behavior of male Cyclocephala distincta, focusing on the infl uence of contact signaling and movement over mate selection in a series of controlled bioassays. Roughly half of the males chose a conspecifi c female over another male, readily engaging in copulation upon initial contact. The remainder males required more experience, acquired through successive mounts on both females and males. Eventually, all focal males invested in copulation with females. When faced with the choice for a live or an inert conspecifi c female, male C. distincta preferred the former in 76% of cases, although we also recorded sexual investment on inert females (10% of cases). In paired experiments with an inert female or a male, nonetheless, focal males signifi cantly opted for the opposite sex, and that included mating with the inert females. Innate characteristics of the females of C. distincta are evaluated by males synergistically, and not separately, in discriminating potential sexual partners.