Location: Imported Fire Ant and Household Insects
2013 Annual Report
The goal of this project is to develop new functional genomic resources for fire ants. A comparative study of ants of the two social forms of fire ants revealed the genomic region responsible for two divergent forms of colony social organization in fire ants. The results demonstrate that show that this genomic region is part of a pair of heteromorphic chromosomes having many of the key properties of sex chromosomes. Importantly, the non-recombining region comprises most of the genes with demonstrated expression differences between individuals of the two social forms. These findings highlight how genomic rearrangements can maintain divergent adaptive social phenotypes involving many genes acting in concert by locally limiting recombination. A second study was completed that employed newly developed whole-genome microarrays to characterize the gene expression patterns underpinning different behavioral phenotypes of foundress fire ant queens. The results demonstrate that in fire ants, social environment (colonies started by single-queen vs. multiple-queens) plays a major role in the determination of the patterns of gene expression, while the physiological state and the social rank of founding queens are only secondary. These results highlight the powerful influence of social environment on regulation of gene expression patterns, physiology and, ultimately, social behavior of animals. Monitoring: Progress was continuously monitored through direct interactions with staff.