Q&A: Professor Catherine Bevier

 

Professor Catherine Bevier on sunfish, frogs, and a biologist's need to keep asking questions

 

Last year while strolling around Johnson Pond, Catherine Bevier, Clare Booth Luce Assistant Professor of Biology, stumbled upon something she hadn't noticed before"dozens of sunfish nests in the shallows. She spent this summer in Waterville, studying the reproductive behaviors of the fish and the mating habits of mink frogs. Bevier (pronounced beh-VEER) spoke with Colby about her research.

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You really just discovered these sunfish last year?
Yes, last summer we were out taking a hike and I looked at the pond and noticed these nests. I hadn't noticed them before because they're very seasonal. I always get curious when I see nesting behavior, especially if it's a system that's easy to study. So I thought, "Wow, what a nice place to do a study. Right on campus."

Have you studied sunfish before?
No, until now I had only caught them as a kid, off the end of a dock in New York. In my animal behavior class though, we've talked quite a bit about blue-gilled sunfish. They've been very well studied in terms of different male reproductive strategies.

Why are you studying these fish? Solely for observation's sake or do you hope to predict anything?
We're generating some hypotheses, especially about territoriality and mating strategies. All the nests are built and maintained by males, but there are also other strategies that males take on to make themselves more attractive to females. For instance, you have the sneaker males. They don't hold territory, but if they see a female and a male spawning in a nest, they'll try to get their sperm to fertilize some of the eggs. So even though they're not putting any energy into maintaining a territory, they can still continue their genetic line.

So the sneaker male is one of the hypotheses you're testing?
Well, we're trying to see if this behavior does occur, and we're also observing other characteristics of nests. My research assistants, Spencer Koury ['06] and Daniel Breen ['06], noticed that the nests toward shore are smaller than those away from shore. Maybe more subordinate and less desirable males have larger nests, hoping that the large nest will make them attractive to females. This summer we'll be measuring the nest size, and we also have a light meter to see how much sunlight is getting into the nest.

Why is sunlight so important to these fish?
Sunfish are prone to putting on displays when the sun is out. Also, they have beautiful iridescence, which is both attractive to females and a factor of competition to other males.

Have any of your hypotheses proved true?
Yes, I was hoping that we'd see some sneaker male behavior, and we've noticed that. There are definite differences between nest sites. We've got about thirty sites identified, and we're doing focal studies. In fact, what I'd like to test further is a hypothesis in sexual selection theory. It's said that males with a better immune system are more attractive to females. A better immune system may be reflected in their body size and body coloration, like has been shown in turkeys and peacocks. Brighter males have a better immune system and are more successful with females.

How do you plan to go about testing the immune system hypothesis?
I've been talking to Lynn Hannum, the immunologist in the biology department, about collaborating to see if the brighter males have a better immune system and eventually getting some of the behavioral data to show that those are indeed the males being chosen by females.

Is there always a fear that your hypothesis won't prove true?
Yeah and that's fine. If you can't find support for a hypothesis then you go on to the next one. Every study is going to lead to three, four, five new questions, and that's just great. It's exciting.

What about the frogs you're studying? Any particular area of interest there?
Yes, this is my sixth season working with mink frogs over at a bog in Mercer. It's a species that's not very well known. In the past I've published on their vocal repertoire"the types of calls that they produce. This summer I'm continuing an experiment to see how males and females react to the different kinds of calls being produced, so I'm doing some choice tests.

Have you faced any difficulties while conducting this research?
Yes, my field site for the mink frogs totally changed this summer. It's a series of three ponds intersected with beaver dams, and two of the beaver dams breached, draining two of the ponds. So I was left with only one pond. There were five different species of amphibians trying to breed in there, competing for space. It really didn't look possible to continue the kind of work that I was doing last summer.

That kind of setback must have been disappointing.
Yeah, but where there's a will, there's a way. Just up the road there was another site. Thankfully I had some pretty good contacts around the state that helped me find feasible places to conduct my experiments.

Will you eventually publish or present all your research?
Both. Usually when I start a new project I spend one season getting a feel for the animal"how we can study it, if we can mark them individually, and then really defining the hypotheses we want to test. The next season we usually get into the nitty gritty of gathering data.

Does your research usually involve a lot of students?
At any given time I have between two and four students working with me. I've often also had students come back and continue past research.

So, it's relatively easy to find students interested in your work?
Absolutely. I usually have a full lab by February. Students seek out these kinds of jobs. I think it's a great opportunity for those potentially interested in research to see if they like it. Especially if the students are interested in professional fieldwork"this gives them a chance to see whether or not they can sustain their enthusiasm. And they're such a great help to me. I couldn't do it without them.