Experimental evidence of polyandry and prolonged copulations in Photinus palaciosi, a synchronous firefly with brachypterous females (Coleoptera: Lampyridae)

Abstract

Males of some species of the firefly Photinus produce nutritious spermatophores (nuptial gifts) the production of which is associated with a specific reproductive morphology. In fireflies and other insects, the production of nuptial gifts favours the evolution of polyandry. On the other hand, in fireflies, wing reduction (brachyptery) in females is associated with the lack of nuptial gifts. P. palaciosi is a synchronous firefly with brachypterous females, which would indicate an absence of nuptial gifts and a monandrous mating system. However, the reproductive morphology of P. palaciosi is like that of species producing nuptial gifts, which indicates this species should be polyandrous. Here, the results of an experimental study designed to test if females of the synchronous firefly Photinus palaciosi are polyandrous or monandrous are reported. The duration of copula was determined because this trait is associated with absence/presence of nuptial gifts in fireflies: it is very short (few minutes) in species lacking nuptial gifts and long (hours) in gift-giving species. More than sixty percent of the females mated with several males and the duration of each copulation was long. Thus, these results, together with those of previous studies on the morphology of the reproductive system, strongly indicate that males produce spermatophores (which usually contain nutrients and are, thus, considered nuptial gifts), which provides a possible explanation of both polyandry and prolonged copulations in P. palaciosi.

Keywords

• mating behaviour
• mating system
• copula duration
• mate guarding