The evolution of polyandry: an examination of the genetic incompatibility and good-sperm hypotheses

I have examined the adaptive significance of polyandry using the Australian field cricket Teleogryllus oceanicus. Previous studies of polyandry have e xamined differences in offspring production by females mated multiply to a single male or females mated multiply to different males. Here I combine th is approach with a study of parentage of offspring produced in the later gr oup. Females mated to two different males had a higher proportion of their eggs hatching than did females mating twice with a single male. Offspring f itness parameters were not effected. There was little evidence to suggest t hat females elevate their hatching success via fertilizing their eggs with sperm from genetically compatible males. Although the average paternity poi nts towards random sperm mixing, there was considerable individual variatio n in sperm competition success. Patterns of parentage were consistent acros s females mating twice or four times. Sperm competition success was not rel ated to offspring viability or performance. Thus, the notion that competiti vely superior sperm produce competitively superior offspring is not support ed either. The mechanism underlying increased hatching success with polyand ry requires further study.