Solenopsis invicta ©Alex Wild Photography
A group of researchers lead by Yannick Wurm at the University of Laussane has presented the draft genome of the fire ant Solenopsis invicta. Their findings have been published in the Proceedings of the National Academy of Science. Fire ants, inadvertently introduced to the southern United States from South America in the 1930s, are now of profound economic importance, with annual losses to households, businesses, governments, and institutions of $5,000 million across the United States.
The major organizing principle of societies of bees, wasps, termites, and ants is a reproductive division of labor, in which one or a few individuals (queens and males) specialize in reproduction and the majority of individuals (workers and soldiers) participate in cooperative tasks such as building the nest, collecting food, rearing the young, and defending the colony. Wurm and colleagues found that the genome of S. invicta harbors four adjacent copies of the gene vitellogenin, and that these genes have undergone subfunctionalization with queen- and worker-specific expression, possibly reflecting differential selection acting on the queen and worker castes. They also identified more than 400 putative olfactory receptors of which at least 297 are intact. This represents the largest repertoire reported so far in insects. Some of these and other unique aspects of the fire ant genome are likely linked to the complex social behavior of this species. The Hymenoptera Genome Database is pleased to host the resources developed by this team of researchers.