Meeting Abstract

89.2  Wednesday, Jan. 7  Evolutionary origins and functions of nuptial gifts in fireflies SOUTH, Adam*; STANGER-HALL, Kathrin; LEWIS, Sara M. ; Tufts University; University of Georgia; Tufts University adam.south@tufts.edu

During courtship and mating in diverse insect taxa, males provide females with nuptial gifts in the form of captured prey, spermatophores, or body parts. Such nuptial gifts often provide a net benefit to females by increasing lifetime fecundity, although associated fitness costs have also been documented in some species. Nuptial gifts thus play a key role in reproductive physiology, insect mating systems, and sexual selection, yet the distribution of such gifts across related taxa is poorly understood. During mating in several firefly species, males transfer a proteinaceous spermatophore that provides a net fitness benefit to females, while other species lack spermatophores. Additionally, some firefly species exhibit a sexual wing dimorphism in which females are flightless due to a lack or reduction of wings. Many firefly adults are non-feeding, so reproduction depends on resources acquired during larval stages. We hypothesized that lacking a sexual wing dimorphism (females capable of flight) might select for nuptial gifts, based on a higher potential for male-derived nutrients to increase female fecundity. Ancestral trait analysis based on a molecular phylogeny suggests that both nuptial gift production and the absence of sexual wing dimorphism were the ancestral traits in fireflies. In addition, we used Pagels test of correlated character evolution to determine that sexual wing dimorphism is significantly correlated with the loss of nuptial gifts. This is the first phylogeny-based analysis in any insect taxa that has considered the relationship between life history traits and nuptial gift evolution. Our results provide new insight into the selective forces driving the evolution of nuptial gifts and associated sexual behaviors.