Sexual conflict and cryptic female mate choice in the Coelopidae

This thesis describes a collection of experiments investigating sexual conflict and cryptic female choice in the Coelopidae. An experiment examining the effect of the alpha-beta inversion karyotype in C. frigida revealed that male karyotype has no direct influence on male willingness to mate or other mating interactions, however, male size and karyotype have an influence over the female rejection response. There appears to be no clear genetic effect of female karyotype on female rejection behaviour, which leaves the question as to why alpha-alpha females are mated with more often, unanswered. Females were found to mate hundreds of times in their lifetimes, making C. frigida an extremely promiscuous species with great potential for post-copulatory sexual selection to occur in this species. Evidence was found for cryptic female choice as females may have the ability to select sperm from within the ejaculate of a single heterokaryotypic male to produce fitter heterokaryotypic offspring. Time interval between copulations and the order of polyandrous copulations with males of different chromosomal karyotypes were found to interact in their effects on P 2values. The mating systems of 5 Australasian coelopids were examined and a comparative analysis of sexually antagonistic co-evolution in 13 coelopids was carried out. Female-mediated sexual conflict appears to have played a role in increasing male size and variation in male size, though large male reluctance to mate may mask evidence for antagonistic co-evolution. ISSRs were found to be a very useful tool in determining genetic variation in C. frigida and the possible future use of this technique in paternity analysis is discussed.