The Diversity of Damselflies
As an evolutionary ecologist, Adam Siepielski is interested in combining evolutionary and ecological studies to understand what shapes the diversity and abundance of species in an environment.
“One of the most important biological questions is why there are often so many ecologically very similar species found together in an environment,” said Siepielski, an assistant professor in the Department of Biological Sciences. “Given the recent uptick in species extinction rates and thus loss of species diversity on this planet, understanding how biodiversity can be maintained has gained a sense of urgency on the part of biologists.”
Siepielski is in the third year of a research project supported by a $400,000 grant from the National Science Foundation to investigate the contributions of ecological and evolutionary processes in the community structures of the damselfy, an abundant insect similar to the dragonfly that is smaller and has a slimmer body.
The damselfly (pictured above) is an ideal organism to test opposing views for high levels of species diversity routinely found in ecological communities, Siepielski said. The common view is that “niche” differences in species, that is, species interacting with the environment differently, allow species diversity to be maintained in a system.
The other view, not as widely accepted, is that diversity is being lost because species don’t differ ecologically enough, he said. Diversity loss isn’t being noticed because it is occurring at a glacial pace.
“These opposing views have their origins in theory first developed in population genetics” Siepielski said. “Our project is testing the hypothesis that species diversity can depend on a little bit of both, that species niches occur but so does the slow loss of diversity, but it all depends on geography and evolutionary history.”
One of the striking features about the evolutionary history and geography of damselflies is that there is a major locational division of damselfly descendants. The damselfly species in the northern hemisphere are very young. Damselflies in the south are a much older group.
“The longer a species has existed, the better chance ecological differences evolve,” Siepielski said. “We’re testing the hypothesis that in the north you should see evidence of the species being very similar and thus the diversity not being maintained, whereas in the south there should be niche differences and the diversity is being maintained. This provides a way of thinking about how different views of community structure can occur simultaneously.”
Siepielski was awarded the NSF grant when he was on the faculty at the University of San Diego and $202,000 was transferred to the U of A when he joined the biological sciences faculty last fall.