CYTOPLASMICALLY INHERITED PARASITES AND REPRODUCTIVE SUCCESS IN TRIBOLIUM FLOUR BEETLES

Numerous insect species harbour cytoplasmic microorganisms, Wolbachia pipientis, that mediate reproductive incompatibility. Males infected with this parasite are reproductively incompatible with uninfected females. All other crosses are fertile; however, the microorganism seems to have a measurable negative effect on fitness. This study determines whether the presence of the microorganism causes deviations from non-random fertilization. Such deviations may benefit either the parasite or the host. Fertilization was found to be non-random in a way that benefits the parasite. This finding is consistent with the hypothesis that parasites manipulate host behaviour to enhance their rate of spread through a population. © 1993 The Association for the Study of Animal Behaviour. All rights reserved.