Research

As part of postdoctoral research, I am using comparative genomics and ecological approaches to investigate the factors that generate and maintain variation in a complex trait, floral fragrance detection, which mediates many interactions between plants and insects. In insect, chemosensory gene families on the antennae participate in recognizing floral fragrances. I will unravel ecological factors that contribute to the genomic evolution of floral fragrance detection in the highly co-evolved symbiosis between figs (genus Ficus) and fig wasps (superfamily Chalcidoidea) through 3 studies: (1) I will examine chemosensory gene family copy number variants (CNVs) in a comparative, community context to determine if convergent evolution at the phenotypic level attraction to the same host fragrance is reflected at the genomic level. (2) To generate insight into ecological specialization, I will examine CNVs between specialists associated with a single fig species and generalists associated with 2-4 hosts. (3) Combining analysis of CNVs and genomic architecture with estimates of effective population size, I will also investigate how fig wasp population dynamics have affected their chemosensory gene family evolution.

Symbiotic interactions are fundamental to ecosystem functions and have shaped Earth's biodiversity. These interactions impact population dynamics and symbiont coevolution, but many details remain unknown due to limited research. Figs and pollinating wasps form a diverse mutualism, yet there's a lack of studies on host-pollinator associations across geographical ranges. We conducted a targeted study using high-throughput sequencing to assess pollinator diversity and host-pollinator associations in multiple Ficus species. Results reveal changing associations over time and space, suggesting that highly specific symbiotic relationships can break down with environmental or evolutionary shifts. Host-switching and pollinator-sharing are common, facilitating gene flow between Ficus species, with significant implications for mutualism coevolution.

Receptive figs (Ficus) attract their highly host-specific pollinator wasps (family Agaonidae) using volatile organic chemicals. These chemicals vary in type and concentration among fig species and are thought to drive pollinator specificity. However, host switching and sharing among figs and wasps are increasingly recognized. We used genomic data to identify hybrid figs and compared the volatile chemicals they release with those of their parent species. Hybrids shared many compounds with their parents but also exhibited unique compounds not found in either parent (transgressive traits). This suggests that the flexibility of certain enzymes may enable hybrids to produce novel chemical scents. Future research integrating genetics and chemical composition may explain fig and wasp specificity and the evolution of speciation in this pollination mutualism.

In this study, we investigate the genetic differentiation of the widely distributed fig species, Ficus petiolaris , and its associated pollinating wasp, Pegoscapus, using next-generation sequencing data. We explore the role of geographic factors and species-specific traits in shaping their genetic structures. Surprisingly, despite their mutualistic relationship, these two species exhibit different population structures and histories. The Gulf of California acts as a significant barrier for Ficus petiolaris, while Pegoscapus shows weak genetic subdivision across northern and central Mexico but significant differentiation south of the Trans-Mexican Volcanic Belt. We define three subspecies for each species, but their geographic congruence is partial. Despite strong selective pressures, we find that genetic differentiation is influenced more by species-specific traits than shared vicariance events.