Prevalence and Effect of Wolbachia Infection on the Brown Widow Spider

Wolbachia pipentis is a reproductive manipulator and was recently identified in the Brown Widow Spider (Latrodectus geometricus). As this symbiont has not previously been found in the genus Latrodectus, the consequences on the spider’s population dynamics and life history patterns are unknown. In my 1st chapter, I determine that the prevalence of Wolbachia pipentis infection in the Brown Widow Spider ranges from 20% to 92% in the Southeastern U.S. These results suggest that the strain is not an obligate symbiont and does not provide a strong fitness benefit to the spider. In my 2nd chapter, I examine the effects of infection on the spider’s reproduction and juvenile development time, showing no significant difference between infected and uninfected individuals. These results suggest that the strain is not an obligate symbiont nor does it alter the reproductive biology of the spider, as it does in most species. The lack of effect on the host suggests infection is either: i) neutral, and remains in the population by complete maternal transmission or has reached an equilibrium, or ii) affects a trait that was not analyzed in this study.