Research
The Stoy lab research focuses on developing an understanding of the coevolutionary dynamics underlying the persistence and stability of mutualism. How does genetic variation arise in mutualisms and what are the consequences? How do community dynamics alter pairwise evolutionary trajectories? How are mutualisms stabilized in rapidly changing environments? How does organismal integration evolve?
Stoy Lab Research Overview
Our lab aims to advance understanding of the evolutionary genetics and coevolutionary dynamics underlying mutualism stability. We use natural systems, including interactions between Coreid insects and bacterial Caballeronia symbionts. We also leverage experimental evolution and synthetic biology using Saccharomyces ceresivisae. Using this multi-faceted approach, we use an evolutionary genetics framework to address oustanding questions in the field of mutualism, such as....
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Are horizontally transmitted symbiotic mutualisms characterized by network structure?
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Does community-level coevolution shape the evolutionary trajectories of horizontally transmitted symbiotic mutualisms?
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What is the distribution and intensity of coevolutionary interactions within communities?
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How does genetic variation arise in mutualistic interactions and what are the eco-evolutionary consequences?
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What mechanisms underlie the evolution of organismal integration for interspecific mutualims?
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Current Research Areas
Evolution and stability of environmentally acquired symbioses
Squash bugs and their symbionts
Environmentally acquired symbionts experience selection in both the external and host environment. This may result in tradeoffs for symbionts if adaptations for one environment are costly in another. The uncoupling of host and symbiont life cycles also increases opportunities for hosts to acquire exploitative symbionts. Using the interactions between the squash bug Anasa tristis and its bacterial Caballeronia symbionts, our lab aims to identify the evolutionary processes underpinning the maintenance of cooperation in environmentally acquired host-microbe symbioses. We are doing this by evaluating how the differential selection pressures experienced by symbionts affect population structure, whether symbionts experience tradeoffs due to differential selection pressures, and the consequences of the symbiont adaptation to external selective conditions for host fitness. We are exploring these ideas using genomics and cross-infection studies.
Host-symbiont communities and diffuse coevolution
Coreid insects and their bacterial symbionts
Much of our understanding of coevolution between hosts and symbionts comes from empirical work and theory evaluating how pairs of species reciprocally evolve in response to one another. However, these pairwise trajectories are likely altered by the range of interactions experienced within species-rich communities. Increasingly, empirical evidence from mutualisms in nature suggest these community-level interactions play an important role. Using field collections and genomics, we are investigating whether community structure and diffuse coevolution contribute to the maintenance of cooperation between Coreid insects and their Caballeronia symbionts.
Partner fidelity and the evolution of mutualistic rewards
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Opportunities for repetitive interactions between specific partner lineages are predicted to contribute to the maintenance of cooperation. When partner lineages interact across generations, they can impose strong reciprocal selection on one another for the maintenance of beneficial traits in the inhibition of exploitative traits. However, many mutualistic interactions are characterized by promiscuity, such that partner switching frequently occurs, and the fidelity of interaction between specific partner lineages is weak. How cooperation persists and increased rewards evolve in mutualisms with weak partner fidelity is poorly understood. We are currently using experimental evolution of mutualistic S. cerevisiae yeast strains to assess the consequences of temporally varying partner fidelity.
Mutualistically cross-feeding yeast
