Utah State University’s Ecology Center is hosting biologist Priyanga Amarasekare this week. Priyanga Amarasekare is a Professor of Ecology and Evolutionary Biology at the University of California, Los Angeles. Her research addresses ecological questions in an evolutionary context, using a combination of mathematical modeling and hypothesis-driven experiments in both the field and the lab.
“For a long time, I've been studying an insect community in southern California,” Amarasekare said.
In Amarasekare’s field system, an herbivorous insect is parasitized by two competing insects.
“And they are also specialists, meaning that they cannot attack any other eggs besides the eggs of this species. And that has been very useful because it … allows me to study all the interactions in this community, and it has only four species, … but it embodies a whole host of species interactions,” Amarasekare said.
One of the parasitoid insects can even kill the other at the larval stage, inside the host egg. Given this competitive advantage, Amarasekare wanted to understand how the two specialist parasitoids could coexist.
"I noticed that the parasitoid that is the poorer competitor is more cold-tolerant. So, it emerges earlier in the year … and has some time to build up in abundance,” Amarasekare said.
To investigate the effect of temperature on the species’ interactions, Amarasekare brought the insects into the lab to measure their birth rates, death rates and developmental rates at different temperatures.
“And we found … it was a combination of those temperature differences and that asymmetry with the predator-prey interaction and competition, and when you put it together, you can get coexistence but ... that second species … that can attack the larvae ... it's on its way to excluding the first species. Except then the winter comes in and resets the system,” Amarasekare said.
Amarasekare said what was really inspiring about this system was that it made her think about climate change.
“And what will happen when it gets warmer, and that first species loses its advantage in being cold-tolerant,” Amarasekare said.
Learn more about Amarasekare’s research here.
