Raw sequence reads of Polyrhachis lamellidens (Hymenoptera: Formicidae). Polyrhachis lamellidens

While most ant species found a colony independently, some socially parasitic ants carry out the colony foundation through the invation of other ant (host) colonies, utilizing their labor force. It has been identified that many socially parasitic ants disguise their cuticular hydrocarbons (CHC) profile, also known as nestmate discrimination pheromones, when invading the host colony. Since the strategy of chemical disguise is widespread in socially parasitic ants, elucidating its mechanism leads to the understanding of the evolutionary history of social parasitism. However, details are still unknown, as they are only inferred from circumstantial evidence obtained from ecological observations. In this study, we investigated the mechanism of chemical disguise in the new queen of a temporary socially parasitic spiny ant (Polyrhachis lamellidens) by measuring the CHC profile, performing the tracing assay of labeled substances, and analyzing gene expression levels. First of all, after the rubbing behavior against the host workers, the CHC profile in P. lamellidens shifted to pronounced peaks closely resembling that of the host workers. We also observed reduced aggressive behaviors of the host ant against P. lamellidens after rubbing behavior. In addition, P. lamellidens acquired the artificially applied labeling substances from the host workers through rubbing behavior, while the gene expression profiling showed that there was no change in the expression of CHC synthesis-related genes during this behavior. These results suggest that P. lamellidens directly obtains host CHC through the rubbing behavior, which enables disguise during colony invasion.