_NATURE ENVIRONMENT Myrmecology

_Stomach Bugs

Ants’ stomachs, and the tiny organisms living there, may provide tiny models of what goes on inside our own bodies.

_Jacob Russell

Russell is an associate professor of biology and head of the Department of Biology’s Russell Lab.

An ant might not look like much: a speck of a pest in your kitchen, perhaps. But what’s going on in the stomach of those ants can tell a story far beyond the cleanliness of your cupboards, says Jacob A. Russell.

From his position as head of the Russell Lab, he studies all of the species of microbiomes within ant stomachs. These species live together symbiotically in ant guts and together play important roles in the ants’ nutrition, defense, reproduction and evolution. Studying these microbiomes can not only map ant evolution, but serve as a model to study what goes on in our own bodies.

Russell is looking for microbiome differences across two spectrums: Within colonies, researchers are looking at how those stomach microbes are transferred from the queen to the worker ants, and if there are differences between generations. Across regions, researchers are comparing microbiomes between species, and whether or not those differences affect what each species eats.

“Microbes could really have important impacts on the origins and diversification of different ant groups,” says Russell. If, for example, a species of ants stopped feasting on the carcasses of dead animals and instead switched to a plant diet, something happened. Either the food supply or the microbes changed.

“These shifts seem to have come in association of them acquiring dense communities of bacteria in their guts. What came first? It’s important to know if we want to understand ant evolution,” he says.

Cephalotes Flower

TREE_HOPPER

Cephalotes atratus ants live in the forest canopy of South and Central America.

Ants are an ideal animal to study for a lot of reasons, says Russell. First, there are a lot of them. Second, there’s already a long history of data about ants. Third, ant microbiomes are relatively simple. Each ant has five or six dozen bacteria in their stomachs, compared to the hundreds that each human stomach carries. Learning about the symbiotic communities in a small setting can give researchers a basic understanding of how microbes interact, which can then be applied to larger, more complex systems. If researchers are looking to study the much more complex microbiome of the human, ants could be one place to start.

“We hope that this could be a type of model to study our own gut microbiome,” Russell says, adding that understanding how they work can further research about nutrition, pathogen defense and digestion.