Honors Students' Abstracts
Wolbachia and Sex Ratio Deviation in the Bolas Spider Mastophora cornigera
(Araneae, Araneidae)
Lauren Kubeck, Alexandra Reivitis
Bacterial infections of Wolbachia are present in some spiders species where they can affect the sex ratio of spider offspring. This study tries to understand whether there is a correlation between the presence of
Wolbachia in the egg sacs of the bolas spider
Mastophora cornigera and the sex ratios of the offspring in each egg sac. In a previous project (2008-2010), 13 egg sacs of
M. cornigera were collected from five sites in Los Angeles and Orange Counties and recorded their sex ratios, in addition to those of 8 previously collected egg sacs. They found that two of the 21 individual egg sacs deviated significantly from the 1:1 male/female ratio; one egg sac was male biased (74:26 M/F) and the other egg sac was female biased (19:42 M/F). The current study seeks to determine whether
Wolbachia is present in
M. cornigera and whether this bacterium is correlated with skewed sex ratios in some clutches of spiderlings. Since most clutches from the same mother were not significantly skewed in their M/F sex ratios during the prior investigation, this study will also determine if the bacterium selects certain egg sacs to have skewed sex ratios. If any egg sacs are found to contain
Wolbachia and also have skewed ratios, we will focus on potential mechanisms for deviations from a balanced ratio. Thus far, we have adapted published protocols to the
M. cornigera system and are trouble-shooting them to achieve better results.