CLARKSVILLE, TN – When he first set up the traps along the creeks in Fort Campbell, Trevor Walker did not expect to catch, eliminate and identify so many insects.
“I originally thought maybe 10,000,” said the Maiden, North Carolina, native of pursuing a Master of Science in Biology at Austin Peay State University. “But the number kept going up and up and up.”
After about five months of insect collection and six months of counting in an Austin Peay lab, Walker and his team identified 55,085 insects.
It’s true – he and his team captured and counted over 55,000 insects in just 11 months. But the payoff from all that work could be huge — the research could uncover a new way for state agencies to assess water quality.
Why identify 55,085 bugs?
Walker’s work focused on three specific insect groups – mayflies, stoneflies and caddisflies – to see if they frequented the same areas as some bats.
“The reason we’re focusing on these insects is that previous studies have shown that these three orders are extremely intolerant of water pollution,” Walker said. “So if a waterway becomes polluted in any way, shape or form, that will be your first group of insects to go extinct.
“They are the first sign that something is wrong.”
State agencies already track mayflies, stoneflies and caddisflies to assess water quality, and Walker wants to see if they can use bats in the same way.
“Previous studies show that bats concentrate on areas with high insect biomass – lots of insects equals lots of bats,” Walker said. “But no one has looked at what these insects are.”
If bats feed on the same insects that state agencies use to determine water quality, then “we might suggest that bats can also be used as a bio-indicator of water quality. the water”.
Walker relates the idea in a research paper titled “Bat Species Diversity Linked to Stream Health as Described by Intolerant Insect Diversity.”
“Because of the dependence of North American bat species on aquatic insects for forage, we suspect there should be a link between stream health and measures of bat diversity. “, he wrote.
What can 55,085 bugs tell us?
Walker and his adviser, Dr. Catherine Haase, reviewed the data this spring.
“He looked at species richness — which is the number of species there — and ‘evenness’ — whether a bat species is evenly represented,” Haase said. “Between these two measurements, he looked at the actual bat species.”
The team collected insects using Hess samplers, dip nets, dip nets and light traps. They collected bats using mist nets at 25 sampling sites in Fort Campbell. Big brown bats and red bats are common and were captured the most in the study, Haase said. Tricolor bats are endangered and less common.
Walker shared the results in his paper: “We found that bat species richness and evenness had a positive response to family richness (mayfly, stonefly, and caddisfly). But individual bat species play a role in other habitat characteristics, such as food availability, weather, and other temporal characteristics when foraging in these areas.
The results indicate that bat species diversity is linked to healthy streams where mayflies, stoneflies and caddisflies are present.
Understanding our ecosystems
Identifying these types of relationships is key to advancing understanding of our ecosystems, Walker said.
“It’s really important to understand these community relationships because bats do a lot for us,” he said. “I wanted to look at that and incorporate insects as well because I want to encompass stream conservation, bat conservation and insect conservation, because everyone kind of assumes that insects will always be around. “
As Walker tightens his research, he hopes the results will help state agencies do their jobs. Bats are easier to identify, after all.
“Maybe state agencies could go out and set up an acoustic monitor or something, and if a species of bat is around, they’ll know the high-quality water exists,” he said. Walker.
Austin Peay biology graduate students Sarah Zirkle and Sarah Krueger will co-author the paper with Haase and Gene Zirkle, program director and endangered species biologist for Fort Campbell Fish and Wildlife. The group worked on a larger Austin Peay-Fort Campbell investigation into endangered bats at the Army post.
Austin Peay undergraduate biology students Matthew Scott and Harrison Rogers also helped Walker identify insects. Brylea Abed and Sheila Staples assisted with data entry.
Walker will soon start at the South Carolina Department of Natural Resources as a senior bat technician.