Limited spermathecal sperm removal ability in the damselfly Hypolestes trinitatis (Gundlach) (Odonata: Megapodagrionidae)

Abstract

It has been hypothesized that sperm removal ability in male Odonata (damselflies and dragonflies) has promoted sexual conflict over the sperm stored in the reproductive tract of the female. Although there is evidence supporting this hypothesis, most studies have been conducted in a small number of species from specific families. We explored sperm removal ability in the Antillean Megapodagrionidae, Hypolestes trinitatis through examination of specialized structures on the genital ligula (“penis”) and through measurement of sperm volumes stored in the sperm storage organs (bursa copulatrix and spermathecae) at different stages of the copula. Males removed sperm from the bursa, but not from the spermathecae. The penis has four finger-like terminal processes covered by spines which could contribute to sperm removal. Given the width of the penile processes, males could introduce them into the spermathecae to remove sperm; however this does not seem to occur. A possible explanation for the sperm removal pattern of H. trinitatis could be that the penile processes are prevented to reach the sperm stored due to their position in relation to the spermathecae during the copulation.

Keywords: sperm competition, sperm removal, sexual conflict, Odonata, dragonfly, Hypolestes

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