DISTRIBUTION AND REPRODUCTIVE EFFECTS OF WOLBACHIA IN STALK-EYED FLIES (DIPTERA, DIOPSIDAE)

Wolbachia are cytoplasmically inherited bacteria capable of altering t he reproductive biology of their hosts in a manner which increases the ir spread within a population. These microbes can cause cytoplasmic in compatibility, parthenogenesis and feminization of genetic males. Beca use Wolbachia have been associated with female-biased sex ratio distor tion, we used a PCR assay to examine 17 species of stalk-eyed flies (D iptera: Diopsidae), two of which exhibit female-biased sex ratios, for the presence of these microbes. Type A Wolbachia was detected in four diopsid species, three from the genus Sphyracephala, none of which ex hibit biased progeny sex ratios. The reproductive effects of the micro be were examined in one of those species, S. beccarii, by conducting r eciprocal crosses between infected and uninfected strains. In this spe cies, Wolbachia do not cause detectable cytoplasmic incompatibility or reduce host fecundity. In contrast, our results are consistent with a n association between the microbes and enhanced male fertility. Possib le explanations for the pattern of distribution and effects on male fe rtility include a predisposition for acquiring Type A Wolbachia by the se flics and accommodation by the host genome to bacterial presence.