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Biologist Susan Foster and her students study the threespine stickleback in the lab and in the field. These small fish provide big insights into evolutionary biology. |
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Meet the researchers:
Fishy Behavior
Interview with Melissa-Ann Scotti
Biology major Melissa-Ann Scotti '01 thought she wanted to do
pre-med, but while taking Susan Foster's course in evolutionary
biology, she discovered where her real interests lay. Melissa
approached Professor Foster about her desire to become involved in
research while still an undergraduate and together they developed the project
discussed below. Melissa talked about the process of doing research in
the natural sciences in the context of her investigation of aggressive
behavior in male stickleback fish.
How did you come to investigate this
particular topic?I was working initially on Susan's
research into courtship behavior of threespine stickleback fish,
and I became interested in the aggressive behavior that I saw between
male fish. We know that courtship behavior varies between fish populations
and I wondered if variation would also be found in aggressive
behavior.
Before you actually started your project,
did you do reading on similar research conducted by other scholars?Yes. I looked at similar projects to see how the researchers had
performed their experiments, especially the methods they used, to give
me ideas for setting up my own experiment.
Were you trying to replicate the findings
of other scholars, or were you hoping to extend the question somewhat?It was some of both. I wanted to use dummies of male fish in my
experiment, but before I did, I wanted to see whether other
researchers had used that approach and if so, how it had worked for
them.
Can you describe how you went about your
experiment?I isolated about 60 male stickleback, each in its own 20 gallon
tank, gave them nesting material (males are responsible for
nest-building), and adjusted the photo patterns (light patterns of
night and day) to correspond with what they would be like in Alaska at
breeding time. The fish were chosen from three different lakes in
Alaska, about 20 fish per lake. All the fish from one lake make up a
population. The fish were chosen according to age criteria, whether
they had built nests, or had nests at the time. Once each fish was in
his tank, I monitored his behavior to know when he was ready to breed.
When that time came, I introduced a dummy fish into the tank. The same
dummy was used each time. The dummy was created with red
coloration and of a similar shape and size to simulate the male
stickleback--the model can be fairly crude. I stood behind a blind so
the fish couldn't be distracted by me and videotaped the stickleback's
behavior after the dummy had been introduced into the tank for about 5
minutes. Now I'm in the process of analyzing the data.
How did you go about analyzing the
behaviors shown on the videotapes?That was going to be difficult because the fish move very quickly.
We found a scholar at another university who had devised a computer
program for counting behaviors. I would sit in front of the TV screen
with a computer keyboard. Certain keys were programmed to register
specific behaviors. When I saw a behavior occur, I would press the
appropriate key and the computer would make a record. Then I could
compare trial against trial and population against population,
studying types and frequencies of the exhibited behaviors.
What are the behaviors you would press a
key for?I'm looking at biting--how often and where the fish bites, whether
head, tail, or flank. I'm suggesting that biting the head might be
considered more aggressive than biting the tail, for example. Another
behavior consists of striking--the fish hits the dummy but doesn't
open his mouth. Other behaviors include fanning his nest and swimming
in a zigzag pattern.
Have you had a chance to evaluate your
data?No, that's the next step, comparing the behaviors of the different
populations.
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Additional Resources
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Melissa-Ann Scotti
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See a video clip