How do animals manage threats of the natural world?
She’s a behavioral ecologist, meaning she studies animals’ behavior in relation to natural habitats. This allows her to learn how it affects their ability to survive and reproduce.
One focus in her lab is antipredator behavior, or how animals survive under the risk of predation.
While most animals can see, many also rely heavily on smells to communicate with each other.
“Many animals use chemicals, called pheromones, to communicate through smells,” Mathis said. “This chemical communication plays a key role in shaping their behavior.”
Mathis is well-known for her research on the hellbender, the largest salamander in North America and one local to the Ozarks.
But her lab’s latest efforts delve into the lives of small, minnow-like fish called darters.
She provides key insight into how darters depend on characteristics of their surroundings for survival.
Diving into darters’ detection methods
As small fish, darters are vulnerable to predators. Nearly anything could eat them.
Darters use chemicals to smell when a predator is present. They also use smell to distinguish predatory fish from those that are not a threat.
“If darters got scared every time another fish swam by, they would never be able to do things like eat or reproduce,” Mathis said. “Being able to make those fine scale distinctions is really important for their survival.”
Darters, like other fish, also have a chemical alarm cue. This cue is a chemical in their skin.
When a predator scratches a darter’s skin, it releases the chemical to warn other darters of a nearby threat.
Color as camouflage
Darters rely on being cryptic, or camouflaged, as a first line of defense. They’re more likely to survive if a predator has a difficult time spotting them.
Some backgrounds allow darters to be more cryptic than others.
Mathis and graduate biology student Sarah White investigate how the rocks darters reside on influences their response to predators.
“This is most important for darters in the case of avoiding being eaten by fish called sculpins,” Mathis said. “Sculpins also live at the bottom of streams and often hide under rocks to ambush their prey.”
Mathis and White look at the color pattern of rocks in the darters’ background to see if it shapes their survival tactics. Their findings so far suggest that it does.
Their next experiment will be to explore whether darters use different color patterns in their surroundings to fend off predators.
“We suspect darters will choose the habitat they’re most cryptic in,” Mathis said. “But we’re still working to discover if they actually do.”
Surviving among contamination
Mines in the tri-state area have not been active for decades. But surrounding streams still contain contamination from their run-off, particularly lead and zinc.
This causes the surrounding streams to have a lot less biodiversity than others.
While some darters are known to be among the few species that can survive in the streams, Mathis and biology graduate student Caleb O’Neal study how the contamination affects their anti-predator behavior.
“Our early findings suggest the streams’ contamination does impact darters’ behavior in ways that makes them more vulnerable to predators,” Mathis said.