Monday, December 10, 2007 - 9:29 AM

Testing for genetic and morphometric geographic structure in the scarab beetle Phyllophaga hirticula

Maxi Polihronakis,, University of Connecticut, Ecology and Evolutionary Biology, 75 N Eagleville Rd, Storrs, CT

Few studies have implemented a comparative framework to assess evolutionary rates of morphological characters to determine whether divergence of genitalic traits parallels population level divergence as tracked by neutrally evolving mtDNA. If genitalia are diverging rapidly as sexual selection theory predicts, it is expected that they would show geographic structure while the genetic data would not. Thus, the goal of the current study is to integrate population level analyses of morphological and genetic data in order to investigate genitalic divergence among allopatric populations of the scarab beetle species Phyllophaga hirticula distributed throughout the eastern United States. Geographic structure of mtDNA and male and female genitalic shape were analyzed using standard analyses such as ANOVA, AMOVA, and Mantel tests, as well as new applications testing for spatial autocorrelation. The results of this study demonstrate that mtDNA haplotypes show significant structure among all populations sampled with more structure in the southern populations than the northern populations. This genetic structure is reflected in the shape of the male genitalia but not necessarily in the female genitalia. Thus, the results do not support the hypothesis that genitalic divergence is contributing to population divergence in this species. In addition, female genitalia do not appear to be following the same evolutionary trajectory as male genitalia.

Species 1: Coleoptera Scarabaeidae Phyllophaga hirticula (may beetle)