This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2021, 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. While learning new research skills, the fellow will use a marine worm to explore a major source of biodiversity. Different populations of animals sometimes begin to evolve differences in how their offspring develop. These population differences can set the stage for the evolution of new biodiversity. They can even lead to the origins of new species. Whether this happens depends on whether members of the diverging populations can still mate and produce offspring. A common barrier to such matings consists of female mate preferences for males with the same developmental traits. Such preferences can reduce chance matings between divergent populations and allow them to diverge further. Thus, they can be major sources of biodiversity. Yet, how these preferences arise is largely unknown. Using genomics, molecular techniques, and behavioral assays, this research aims to uncover the genomic makeup of such mate preferences. In addition, the fellow will develop K-12 lessons, perform public outreach, and mentor students using research data.<br/><br/>The fellow will use the model marine worm system Streblospio benedicti to investigate the role of female mate choice in the divergence of populations that differ in developmental type. In some populations, S. benedicti females produce many small, obligately feeding larvae. In other populations, they produce many fewer, much larger offspring that can develop to adulthood via maternal provisioning. Intermediate developmental types are nearly never found in nature. Yet, they are readily produced in the lab by breeding adults of opposite types. This suggests selection acts against such intermediates in nature. Preliminary evidence suggests female S. benedicti preferentially mate with adult males who had the same larval form as them. Thus, it is possible that a behavioral, prezygotic mating barrier is contributing to population divergence in developmental type. The fellow will use crosses and whole-genome sequencing of females with different mating preferences to pursue this possibility. This research will identify the genetic basis for mate preferences in this system and its association with developmental type and population divergence.<br/><br/>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.