Co-evolution of Insect-Microbial Symbioses
The questions we focus on are:
(a) how do insect-microbial interactions influence insect ecology and diversity;
(b) what are patterns of genomic co-evolution in ancient bacterial-insect symbioses; and,
(c) how are host and symbiont functions and metabolisms integrated on a cellular level.
We are particularly interested in leafhoppers, one of the largest groups of insects that feed on plant sap, as a model system. Leafhoppers depend on at least two obligate symbionts - typically bacteria - for nutrition absent in their plant-sap diets (e.g., phloem and xylem). These bacterial symbionts possess tiny genomes that have been stripped of most essential functions necessary for independent life. Therefore, they require substantial resources from the host to carry out even the most basic cellular functions.
[A] Origins and co-evolution of symbioses sap-feeding insects (Auchenorrhyncha)
One of the primary challenges in establishing a long-term symbiosis is integrating the functions of symbiotic partners. This requirement is particularly the case when hosts depend on multiple partners with incomplete genetic capabilities. Different bacterial species likely require specific cellular and metabolic inputs from the host. However, it remains unclear how hosts adapt to their various partners and whether they evolve distinct genetic mechanisms to support them. To explore this question, my lab has developed multi-omic experiments and techniques to understand how ALF manages its two obligate symbionts, Sulcia and Nasuia.
[B] Functional integration of symbiotic partners
One of the primary challenges in establishing a long-term symbiosis is integrating the functions of symbiotic partners. This is especially true when hosts depend on multiple partners with incomplete genetic capabilities. Different bacterial species likely require specific cellular and metabolic inputs from the host. However, it remains unclear how hosts adapt to their multiple partners and whether they evolve distinct genetic mechanisms to support them. To explore this question, my lab has developed multi-omic experiments and techniques to understand how ALF manages its two obligate symbionts, Sulcia and Nasuia.
[C] The role of nutritional symbioses in adaptive species radiation
Animal-bacteria symbioses have shaped diversity by providing hosts with novel adaptive traits. While selection operates to maintain mutualistic traits in both hosts and their symbionts, bacteria experience genome degradation and display selfish evolutionary tendencies. These processes likely influence host speciation and adaptation by reinforcing reproductive isolation, limiting environmental tolerance, and restricting the dietary range of hosts. However, the role of these mechanisms in shaping host-symbiont co-adaptations and diversification is poorly understood. To address this question, we are developing a project that uses the endemic Hawaiian leafhopper, Nesophrosyne, and its adaptive radiation to understand how symbioses influence speciation and adaptation. The Hawaiian Islands provide a natural evolutionary experiment to test such questions due to their diverse, time-stratified, and replicated habitat formation.
