Promiscuous females avoid inbreeding by controlling sperm storage


  • A.B. uses molecular techniques to answer behavioural questions related to sexual selection and polyandry in insects. D.N. was an undergraduate student on this project and is about to start a PhD on maternal effects in milkweed bugs. T.T. uses insects and other model systems in the hope of improving our understanding of speciation and the evolutionary consequences of sexual reproduction.

Tom Tregenza, Fax: +44 1326 254205; E-mail:


Recent studies in a variety of species have shown that polyandrous females are somehow able to bias paternity against their relatives postcopulation, although how they do so remains unknown. Field crickets readily mate with their siblings, but when also mated to an unrelated male, they produce disproportionately fewer inbred offspring. We use a new competitive microsatellite polymerase chain reaction technique to determine the contribution of males to stored sperm and subsequent paternity of offspring. Paternity is almost completely predicted by how much sperm from a particular male is stored, and unrelated males contribute more sperm to storage and have a corresponding higher paternity success.