Infections with Wolbachia, Spiroplasma, and Rickettsia in the Dolichopodidae and other Empidoidea

Vertically transmitted reproductive parasites are both extraordinarily widespread and diverse in their effects on their invertebrate hosts. In addition to causing skewed population sex ratios via male-killing or feminization, such bacteria can further cause cytoplasmic incompatibility or parthenogenesis. Previous surveys show that the microbes Wolbachia and Spiroplasma are common in some dipteran families, e.g. Drosophilidae or Scathophagidae, and are known to be heritable symbionts and affect reproduction in the Diptera. However, little is known of Rickettsia infections and detailed surveys targeting other Dipteran families are lacking. Here 329 samples of 247 species of Diptera belonging to the Dolichopodidae, Empididae, and Hybotidae (superfamily Empidoidea) are surveyed for the presence of the endosymbionts Wolbachia, Spiroplasma, and Rickettsia. The superfamily Empidoidea contains numerous species, which have been the targets of intense research concerning reproductive traits involved in sexual selection. 151 of the species (i.e. ca. 61%) screened here, including species from key genera such as Dolichopus, Poecilobothrus or Empis, harboured one or more symbionts. Reproductive parasites are thus also common in the Empidoidae, yet effects on hosts remain unclear. Potential endosymbiont-host interactions in this group would hence be worthy of further investigation.

► Reproductive parasites can drastically alter the biology of their invertebrate hosts. ► We survey 247 fly species for infection with three widespread microbial reproductive parasites. ► Interestingly, infections with the microbes Spiroplasma and Rickettsia are more common than infection with Wolbachia. ► We suggest future research on possible impacts of these microbes on their hosts is needed.