March 31, 2011
Discerning the Damselfly’s Dilemma
Under the microscope, the insect looks intimidating, with huge blue-black eyes and an explosion of angular legs covered in prickly hairs that extend along its face and torso.
Biology student Andre Morrill starts by pinning down the wings and torso, then he uses a dozen tiny pins to painstakingly take apart the insect. Magnified, it looks like a prehistoric monster. In many ways it actually is prehistoric, the ancestors of this beast flapped their wings beside the first reptiles on earth, in the late Paleozoic era.
With the naked eye it looks less like a monster and a lot more like a small dragonfly. It’s a damselfly, a smaller bug closely related to dragonflies.
Morrill is researching parasitism in damselflies. He’s taking this bug apart in order to count the parasites that cling to the bug’s torso and the lining of its abdomen. The big question for Morrill is whether endo and ecto (internal and external) parasite loads correlate.
In other words, he’s trying to figure out if there is any connection between the number of parasites clinging to the outside of a damselfly and the number clinging to the inside.
Inside this damselfly, he finds a collection of white lumps. To give a sense of scale, if this were a human, Morrill says, “it would be as if you happened to have twenty hamsters living inside your stomach”.
The coolest part was working with researchers from all over the place
The internal parasites, called gregarines, live off the damselfly’s food. “Once they get inside the damselfly, they basically set up shop. They grab on to the intestinal wall and hang out there and eat stuff that passes by,” says Morrill, “the added weight makes it difficult for the damselflies to fly.”
Morrill spent the summer living at a remote research station between Ottawa and Kingston, catching four different kinds of damselflies.
“The coolest part,” he says, “was working with researchers from all over the place, who are asking questions that no one really knows the answers to. It’s one thing to read about their methods, but it’s another to be getting up in the morning and catching bugs together.”
Morrill ultimately collected hundreds of specimens, which he’s now dissecting, one by one.
In April, Morrill will finish his BA in Biology. “Going into it, I didn’t really know what I wanted to do,” he says, “I just knew that biology class throughout high school was always the one where I got excited about seeing how things worked.”
The research experience, says Morrill, has given him a more nuanced view of how science works, “how you go about going through that process of asking a question that no one really knows the answer to, and then figuring out a way to answer it, and then going out and doing it.” Answering a research question while living in a “cabin shack by a lake” all summer, he adds with a smile, was a definite plus.
Surrounded by his dozens of vials of insects, Morrill counts the damselfly’s parasites and records the number. He picks up what’s left of the bug with a tiny pair of tweezers, drops it back into the vial, and adds it to the growing pile of dissected specimens. “The other big thing I’ve gained,” he says, “is I’ve gotten really fast at dissecting bugs.”
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