Even the smallest creatures can cause mayhem. Take the eastern mosquitofish, for example. No bigger than a finger (the guppy-like animal averages between 1.5 and 2.5 inches long), this invasive species is wreaking havoc on native creatures, even right here in Granville. In fact, mosquitofish are significantly affecting populations of larger fish and frogs by eating their eggs.
That’s why they’ve grabbed the attention of Biology Professor Geoff Smith and his three Anderson Summer Scholars, Maggie Jones ’16, Mallory Smyk ’15, and Jeremy Hollis ’16. The group formed after the three students approached Smith individually, each seeking an opportunity to help him in his research of herpetology, or the study of amphibians.
“Mosquitofish are a problem across the states,” says Jones, a biology and creative writing double major from Elkins, W.Va. “So it’s interesting to look at the American toad and wood frog, the two native species we studied over the summer, and see what that impact might look like here.”
Using 68 cattle tanks (large plastic aquariums) filled with pond water and housed in the Bio Reserve, the group looked at two separate amphibian species to see how they reacted to the presence of mosquitofish. Three separate tanks were used to investigate: a control treatment (with no mosquitofish), a treatment where the mosquitofish had free reign of the tank, and a treatment where the mosquitofish were contained by mesh in the center of the tank, keeping the tadpoles in the presence of their chemical cues or pheromones but out of harm’s way.
Once the tadpoles got their back legs, the group pulled the frogs and toads out of the tanks and measured body mass, limb length, head width, body length, and jumping ability.
“We took about 2,500 measurements, so our sample size was huge,” says Hollis, a theatre and biology double major from Montgomery Village, Md.
With so much material, the trio could examine the data in many ways, but the group was able to make some final conclusions about the figures. For instance, they proved that the mean jumping distance of American toads was lowered when mosquitofish were able to swim freely around toad larvi. They also proved that predator-induced changes in the development of the frogs and toads can translate into different jumping distances.
While the results are interesting, the group, as a whole, enjoyed the process of collecting the data the most. Starting in April they pulled on their waders, took out a Bio Reserve boat, and began collecting mosquitofish and tadpole eggs from several surrounding ponds.
“It was cool to watch the frogs and toads grow from eggs,” said Smyk, a Birmingham, Mich., native with a double major in East Asian studies and biology, who plans on continuing to analyze their findings as a part of a senior research project.
“Plus we got to be outside everyday,” adds Hollis.
And you can’t beat that.