Project description:The goal of this study was to assay the extent of variation in chromatin organization between 3 ant castes (major and minor female workers and males) in one colony of Camponotus floridanus carpenter ant using ChIPseq.
Project description:The goal of this study was to assay the extent of variation in chromatin organization between 3 ant castes (major and minor female workers and males) in one colony of Camponotus floridanus carpenter ant using ChIPseq. 45 samples total: 30 ChIP samples and 3 inputs for total histone H3, 7 histone H3 PTMs and RNA Pol II in major, minor, and male ants; CBP in major and minor ants; the major H3K27ac sample was replicated. 4 ChIP samples for H3 and H3K27ac in brains of majors and minors, and 2 inputs. 2 RNAseq samples for major and minor ants head+thorax; 4 RNAseq samples for brain (majors and minors with 2 replicates each).
Project description:The organized societies of ants include short-lived worker castes displaying specialized behavior and morphology and long-lived queens dedicated to reproduction. We sequenced and compared the genomes of two socially divergent ant species: Camponotus floridanus and Harpegnathos saltator. Both genomes contained high amounts of CpG, despite the presence of DNA methylation, which in non-Hymenoptera correlates with CpG depletion. Comparison of gene expression in different castes identified up-regulation of telomerase and sirtuin deacetylases in longer-lived H. saltator reproductives, caste-specific expression of microRNAs and SMYD histone methyltransferases, and differential regulation of genes implicated in neuronal function and chemical communication. Our findings provide clues on the molecular differences between castes in these two ants and establish a new experimental model to study epigenetics in aging and behavior.
Project description:BackgroundCamponotus floridanus ant colonies are comprised of a single reproductive queen and thousands of sterile female offspring that consist of two morphologically distinct castes: smaller minors and larger majors. Minors perform most of the tasks within the colony, including brood care and food collection, whereas majors have fewer clear roles and have been hypothesized to act as a specialized solider caste associated with colony defense. The allocation of workers to these different tasks depends, in part, on the detection and processing of local information including pheromones and other chemical blends such as cuticular hydrocarbons. However, the role peripheral olfactory sensitivity plays in establishing and maintaining morphologically distinct worker castes and their associated behaviors remains largely unexplored.ResultsWe examined the electrophysiological responses to general odorants, cuticular extracts, and a trail pheromone in adult minor and major C. floridanus workers, revealing that the repertoire of social behaviors is positively correlated with olfactory sensitivity. Minors in particular display primarily excitatory responses to olfactory stimuli, whereas major workers primarily manifest suppressed, sub-solvent responses. The notable exception to this paradigm is that both minors and majors display robust, dose-dependent excitatory responses to conspecific, non-nestmate cuticular extracts. Moreover, while both minors and majors actively aggress non-nestmate foes, the larger and physiologically distinct majors display significantly enhanced capabilities to rapidly subdue and kill their adversaries.ConclusionsOur studies reveal the behavioral repertoire of minors and majors aligns with profound shifts in peripheral olfactory sensitivity and odor coding. The data reported here support the hypothesis that minors are multipotential workers with broad excitatory sensitivity, and majors are dedicated soldiers with a highly specialized olfactory system for distinguishing non-nestmate foes. Overall, we conclude that C. floridanus majors do indeed represent a physiologically and behaviorally specialized soldier caste in which caste-specific olfactory sensitivity plays an important role in task allocation and the regulation of social behavior in ant colonies.