Postdoctoral Fellowship: PRFB: Relaxed kin selection in unicolonial ants: adrift in the evolutionary doldrums

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2024, Integrative Research Investigating the Rules of Life Governing Interactions Between Genomes, Environment, and Phenotypes. The fellowship supports research and training of the fellow that will contribute to the area of Rules of Life in innovative ways. This research will advance understanding of the Argentine ant, Linepithema humile, one of the world’s most destructive invasive species. In its invasive range L. humile loses its ability to distinguish family members from unrelated individuals and forms immense ‘supercolonies’ that can cover hundreds of square miles. Evolutionary theory predicts that the disruption of family structure should reduce the efficiency of natural selection on unicolonial ants. This research will empirically test the unicolonial degradation hypothesis, which predicts that due to relaxed selection, populations of unicolonial ants should degrade over evolutionary time. The research will advance understanding of an important organism that has significant negative impacts on native ecosystems and human agriculture worldwide. The project will also support scientific outreach and education through the establishment of a public science program at the Oakland Farmer’s Market and the development of course materials aimed at using ants to teach evolutionary biology to high school and undergraduate students. The research will compare non-unicolonial L. humile collected from its native range in Argentina with unicolonial L. humile collected from its invasive ranges in the United States. Genome sequencing of ants collected from both ranges will allow comparison of genomic degradation, particularly in genes relating to worker ant function. Laboratory assays of living ants will be used to look for evidence that workers from invasive populations are less functional or more selfish relative to workers from native populations. These assays will involve various metrics of captive colony fitness, foraging efficiency, and effectiveness at caring for eggs and larvae. Other assays will compare social behavior by algorithmically tracking individual ants using video footage. Collectively the fellow will gain experience with field data collection, genomics, and behavioral and motion tracking assays. The work will test key predictions of powerful theory related to the evolution of cooperation and conflict, and underscore how shifting into a new environment can profoundly impact an organism’s behavior and role within an ecosystem. Additionally, the research will help inform management decisions centered on mitigating the damage caused by invasive ants. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.