Prolonged Copulation in Oak Bushcrickets (Tettigoniidae: Meconematinae: Meconema thalassinum and M. meridionale)

Abstract

In the majority of bushcrickets, copulation terminates with the transfer of a spermatophore which consists of two parts: an ampulla which contains the sperm and a spermatophylax which the female eats during sperm transfer. Recently, the function of the spermatophylax in bushcrickets has heen the subject of considerable debate. Here, I describe prolonged copulation following spermatophore transfer which appears to replace the spermatophylax in function in Meconema meridionle and M. thalassinum. I contrast this with the more usual copulatory behavior and spermatophores of the related Cyrtaspis scutata. In M. meridionale and M. thalassinum, copulation following spermatophore transfer continues for an average of 81 and 17 min. respectively, and there is no spermatophylax. In Cyrtaspis scutata, on the other hand, copulation following spermatophore transfer lasts for only one minute, thirty seconds and males produce a spermatophylax. As predicted by the hypothesis that prolonged copulation following spermatophore transfer functions to ensure complete ejaculate transfer, the longer duration of copulation in M. meridionale, compared with M. thalassinum, was found to be associated with the production of significantly heavier spermatophores which contained more sperm. The presence of the spermatophylax in the Meconematinae and virtually all other bushcricket subfamilies suggests that prolonged copulation has replaced this structure in the genus Meconema. The occurrence of prolonged copulation following spermatophore transfer in other members of the sub-order Ensifera is reviewed. (Key Words. Prolonged copulation, nuptial feeding, spermatophylax, Tettigoniidae).