ECOLOGY AND EVOLUTION OF HOST-MICROBE SYMBIOSeS
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, comparative genomics, genetic engineering, and in vivo experiments to study the evolution and function of gut microbiomes of social bees.
Please feel free to get in touch by email (tobin dot hammer at utexas dot edu) if you have any questions or would just like to discuss bugs and microbes!