Project description:We performed a whole-genome transcriptomic analysis of pleometrotic queens infected by SINV-1, SINV-2 or co-infected with both viruses, to characterize patterns of gene expression associated with viral infection and identify genes responding differentially to the two viruses. We sampled fire ant queens in Gainesville, Florida, immediately after a mating flight. We arranged them in pairs based on having similar weights (range ±0.2 mg) to allow pleometrotic colony founding. We housed paired queens in nesting tubes in claustral conditions (no food or water) for one month. Thereafter, we collected queens in dry ice, we isolated total RNA from whole bodies and used it to quantify SINV-1 and SINV-2 viruses with real-time PCR. We selected 2 queens that were virus-free as controls, 3 SINV-1-infected, 4 SINV-2-infected and 11 co-infected by both viruses. These samples were processed for microarrays analysis.
Project description:Social insect queens and workers can engage in conflict over reproductive allocation when they have different fitness optima. Here, we show that queens have control over queen-worker caste allocation in the ant Cardiocondyla obscurior, a species in which workers lack reproductive organs. We describe crystalline deposits that distinguish castes from the egg stage onwards, providing the first report of a discrete trait that can be used to identify ant caste throughout pre-imaginal development. The comparison of queen and worker-destined eggs and larvae revealed size and weight differences in late development, but no discernible differences in traits that may be used in social interactions, including hair morphology and cuticular odours. In line with a lack of caste-specific traits, adult workers treated developing queens and workers indiscriminately. Together with previous studies demonstrating queen control over sex allocation, these results show that queens control reproductive allocation in C. obscurior and suggest that the fitness interests of colony members are aligned to optimize resource allocation in this ant.
