Inside USD

Insects May Hold Keys to Biodiversity

Thursday, October 3, 2013

Biodiversity is a big topic. And damselflies are small insects. But it turns out the latter may be able to teach us a lot about the former.

University of San Diego assistant professor of biology Adam Siepielski and two students explored the possibility in a field expedition to dozens of lakes and ponds throughout California this summer. Supported by a four-year National Science Foundation grant for $400,000, Siepielski and the students traveled up the east side and down through the western Sierras, conducting observational studies and field experiments on populations of the colorful dragonfly-like insect in lakes and ponds.

“Impressive levels of species diversity are found throughout the Earth’s different environments,” noted Siepielski (pictured below). “The importance of this diversity to humanity ranges from clean water to medicine to recreation and art. A key question is whether or not mechanisms exist that act to maintain this diversity.”

“Much of the theory developed to understand how species diversity can be maintained is built on the assumption that different species can occupy unique niches,” he explained. Multiple species – in this case multiple species of damselflies – can live together because each species interacts with the environment in different ways.

However many species are nearly identical to one another in how they interact with the environment, he added. “Thus every single species may not occupy its own niche and instead of every species being maintained some are only slowly being lost by random chance. This alternative is known as neutral ecological theory. ”

“I want to know when and where each of these theories works and why” said Siepielski. To do this, Siepielski’s work involves testing the hypothesis that communities at northern latitudes – where populations turn over more often as glaciers transform the landscape over thousands of years — are structured by neutral dynamics while populations in southern latitudes are more stable and evidence niche-based processes. Siepielski and his students will eventually examine damselfly populations from the Canadian border all the way south to Mexico.

During the summer trip to the Sierras, the team quantified key components of the aquatic community food web. “We recorded the abundances of damselflies, as well as predators, prey, vegetation, lake productivity and water chemistry,” Siepielski said. “We’d spend hours at each lake, much of which was spent picking through vegetation to quantify small aquatic invertebrates that are the main food source for damselflies.”

Back at USD, Siepielski is beginning to analyze the results of their samples. Using the data, “we can assess how damselfly community structure varies and what factors might help to explain the variation.”

The hope is to glean knowledge that will go well beyond the damselfly community. “Understanding what mechanisms govern species diversity is critical for developing sound biodiversity management,” Siepielski said. “For instance, our results may reveal that at southern latitudes, conservation plans aimed maintain species diversity may be critical, while in northern latitudes conservation of distinct functional groups may suffice for maintain overall food web structure.”

Matthew Cattivera ‘14, one of the students on the trip, said the experience fostered ”a deeper understanding and appreciation of the reserach process. I gained valuable insight from Dr. Siepielski regarding how to pose a research question aimed at broadening, testing or deepening contemporary knowledge.”

“I would encourage every undergraduate at USD to pursue myriad undergraduate research opportunities offered to us,” added Cattivera who’s majoring mathematics and biophysics. “My experience as a student at the university has exceeded my initial expectations and has taught me that receiving an education at USD amounts to more than just acquiring knowledge in the classroom.”

– Liz Harman

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