HOFFMAN, Eric A.*; GOODISMAN, Michael A. D.; University of Central Florida; Georgia Institute of Technology: Genomic analysis of caste differentiation in yellowjacket wasps

Highly eusocial insects exhibit one of the most remarkable examples of polyphenism, the occurrence of discrete alternative phenotypes produced from a single genotype. Individuals belong to distinct castes (e.g. queens or workers) that exhibit strikingly different morphology and behavior. In this study we used yellowjacket wasps (Vespula squamosa) to address two questions concerning the molecular underpinnings of caste evolution. First, we sought to determine whether molecular differences increase between castes as development proceeds and morphology and behavior become more divergent. Second, we sought to determine whether the patterns of expression in Vespula squamosa are similar to those of the honey bee (Apis mellifera). To investigate these questions we compared expression patterns derived from 11 cDNA libraries constructed from different development stages of Vespula squamosa. We found that expression differences did indeed increase with developmental stage. Moreover, developmental stage was more influential than caste on determining patterns of gene expression. Finally, these patterns were different than patterns of gene expression previously identified in the honey bee. This is likely due to the independent evolution of caste in these two taxa.