Update (July 2020): I'll be joining the Ecology & Evolutionary Biology department at UC Irvine as an Assistant Professor in January 2022! As the time gets closer I'll be announcing opportunities for graduate students and postdocs, but feel free to reach out anytime if you're interested in joining the lab.
ECOLOGY AND EVOLUTION OF microbiomes
Welcome! I am an ecologist and evolutionary biologist fascinated by macrobe-microbe interactions, especially symbiosis. Although much of the rapidly growing field of microbiome research is focused on humans and other mammals, nowhere are the forms and functions of microbial symbiosis so diverse as among the insects. My current work focuses on bees and Lepidoptera (butterflies and moths), two ecologically and economically important groups whose microbiomes are only beginning to be thoroughly explored. The emerging picture so far is that these groups form strikingly variable relationships with microbes, depending on the host taxon and developmental stage in question.
Variability in microbiome form and function across macro-organisms sets up a number of intriguing evolutionary questions. On the host side, why do some taxa or developmental stages "choose" to engage less, if at all, with microbes? What are the ecological and evolutionary costs and benefits of relying on a microbiome versus going solo? How do shifts in microbiome presence or absence occur, both on the timescale of individual life cycles, and of evolution of major lineages? On the microbe side, how often do they switch between being pathogens and beneficial symbionts, and under what contexts? How does the evolution of complex, multi-species microbiomes differ from microbiome monocultures, and how does it depend on the mode by which they are transmitted from host to host? When do the microbes' own fitness interests conflict with those of the host, and how are these conflicts managed?
Beyond exciting and unexpected discoveries about the natural world, the study of insect-microbe interactions has applications in managing agricultural pests, supporting pollinators, and controlling disease vectors. Furthermore, in our era of rapid global change, knowledge of microbiomes will be increasingly important to conserve animal biodiversity. Insect declines in particular are a pressing concern, yet we don't have a good handle on how microbes might mediate insect responses to anthropogenic stressors. The microbes themselves are also worthy of conservation efforts. Many have unique metabolisms that could be useful for medicine, agriculture, and industry, and all have fascinating biological stories to tell.
My dissertation research in Noah Fierer's lab and Deane Bowers' lab at CU Boulder integrated field collections, microbial community profiling and metagenomics, insect rearing and experiments, and natural history. I am currently a postdoc in Nancy Moran's lab at UT Austin, where I am using bacterial culture-based assays, metagenomics, and in vivo experiments to study the evolution and function of gut microbiomes of social bees.
I am also committed to helping break down the barriers in academia that have long excluded Black and Indigenous scholars, and other marginalized groups. The lack of diversity in STEM, including in my own field of ecology and evolutionary biology, is a hindrance to scientific progress, as a huge amount of talent is lost. More importantly, it's a matter of social justice. We have a lot of work to do to before reaching a point where the diversity of scientists (at all levels) reflects the diversity of identities and backgrounds of the population at large, and where everyone can do their science without being held back by discrimination. Those who have benefitted from privilege -- especially cis-heterosexual white men -- have a responsibility to help shoulder this work. Although I've been involved in such efforts, going forward, I'm committed to doing more to use and advocate for equitable recruitment practices, and to create an inclusive environment for my students and colleagues.
Please feel free to get in touch by email (tobin dot hammer at utexas dot edu)!