Mating systems in porcellionid isopods: Multiple paternity and sperm mixing in porcellio scaber latr

Abstract

The enzyme phosphoglucose isomerase (PGI) is encoded by a multi-allelic gene locus in North American populations of the wood louse Porcellio scaber. Laboratory crosses using virgin females have documented the Mendelian nature of PGI inheritance for seven electrophoretically distinct alleles. Several additional rare alleles occur in natural samples. This multi-allelic polymorphism has been employed to determine the frequency of multiple paternity of broods in a natural population by examining the mother-offspring (family) genotype combinations of 20 field-collected pregnant females. The data indicate that the great majority of broods (>80 per cent) are multi-paternal and that each of several males usually makes a substantial spermic contribution to any particular one. © 1978 The Genetical Society of Great Britain.