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Higher-order microbiome interactions

Deciphering the rules governing the composition and assembly of microbial communities requires a quantitative framework that can elucidate the inherent higher-order complexity of interactions within microbiomes. An important factor determining the ability of pathogens to invade and proliferate in a host is the resident microbiota. Quantifying higher-order interactions, involving three or more interactions, in the gut microbiome remains challenging due to the combinatorial complexity involved in determining the set of all possible interactions. Our lab uses insect and plant-microbe models to study higher-order interactions. Parasitic nematodes and duckweed plants are excellent models to test higher-order interactions because their microbial communities represent systems of relatively low genotypic and environmental complexity which allows for controlled experiments. Understanding the conditions under which higher-order microbial interactions can coexist is important in deciphering the microbial composition and structure.

Global change and host-pathogen interactions

Environmental pressures can modulate plant-insect networks by introducing novel pathogens that alter the infectivity, virulence, and susceptibility of endemic taxa. Island insect communities are especially vulnerable to infectious diseases because of their smaller population sizes, low genetic diversity, and lack of resistance to novel pathogens. As a consequence, island ecosystems experience higher rates of species extinctions. Pathogen spillover between invasive and endemic insects can accelerate the evolution of virulence and epidemic outbreaks. Our lab investigates the interplace between global change and host pathogen dynamics on the Galapagos islands in an effort to preserve biodiversity by identifying at risk endemic plant and insect species.

Spatial structure, dispersal, and coexistence

Understanding the drivers of population cycles remains an important challenge for population biology. Natural enemies are a key component of ecological systems and parasites, pathogens and predators are predicted to play an important role in the ecological dynamics of a wide variety of both single hosts and communities. Spatial structure is ubiquitous and the simplistic one host one parasite theory has demonstrated its importance, but it is critical to examine the role of spatial structure in the context of realistic multi-enemy scenarios. We have very little data from manipulative experiments testing the role of spatial structure on population dynamics. We also lack theory on how spatial structure impacts multiple parasite host interactions. We use experimental evolution and modeling approaches to investigate the impact of spatial structure on species interactions.