Rose Larios ’12
Major: Biology
Thesis Advisor: Ethan Temeles

What’s your thesis about?

My thesis is looking at how the foraging behavior of hummingbirds affects the evolution of floral traits of the plants they feed at. It works with the Purple-throated Carib hummingbirds and their preferred plant, the heliconia caribaea species. It’s a heliconia, these very large plants that are made up of multiple stalks that have different inflorescences on them. Inflorescences are these large, colored structures that are made up of racks that are little bowls of nectar, and they kind of build off each other. So what I’m specifically looking at is how competition between the sexes drives the evolution of different color morphs of the heliconia caribaea species. What I did this summer was I traveled to Dominica with my thesis advisor and the other thesis student in our lab. And we spent a month there catching hummingbirds in the wild, the Purple-throated Caribs, and then we brought them to this enclosed garden my advisor set up, which was this really big room made out of mesh screening. And we had the heliconia caribaea plants of the two color morphs, yellow and red, that occur in on that island, in there. So we would bring in a bird and study its foraging over five-hour intervals by itself, and then we would put it in with a competitor of the opposite sex and see how their foraging changed. So what’s interesting is that we found that when the birds were in competition with a member of the opposite sex, they often split up the flowers by color, so, say, the male would visit all yellow plants of the species, and then the female would visit all red. We think that since they pollinate as they forage, this is driving the fact that there’s two color morphs, either maintaining the two color morphs or possibly even driving them to speciation, where there are going to be two different species of the plant altogether. What’s new about this thesis is that floral evolution has been studied for a long time, but the two most popular models it’s been studied with are plant-plant interactions, where maybe there’s pollen competition, or inter-specific pollen will clog a competitor’s organs so that it can’t reproduce anymore; and then the other model that’s been studied is plant-pollinator interactions, which just looks at pollinator preferences, and how that controls the evolution of the plants. But what we’re looking at is more of the interaction between the pollinators. So far this has only been studied mathematically and theoretically in papers; it hasn’t been done experimentally or with field work, so we’re trying to see if our work possibly supports these models, and just look at a good example of evolution in the world.

How did you pick this thesis topic?

Well, in the biology department, you pick an advisor based on the research they’re already doing, and you can pick a topic within their field of research, but since most research requires a lot of resources, you mostly work under what they’re doing.

Who’s your advisor?

Ethan Temeles. So I knew I wanted to work with animal behavior, mostly, and this was a good opportunity to do that. In the past, Ethan Temeles has worked more with looking at character displacement between two species of the heliconia, h. caribaea and h. bihai, which is a similar species. That’s more focused on the plants, so this is a more animal-behavior way to look at it.

So are you expecting this research to possibly lead to job opportunities or graduate school?

Right now I’m planning to go to either graduate or medical school after a year or two working in a research lab, and I’m hoping that this research experience will help me get a job in a lab somewhere next year, or give me an idea of what graduate school’s going to be like, because graduate school in biology is basically a year maybe of classes, and then you work under a PI, a primary investigator, and you just do research for the entire time.

Do you have any advice for other students considering writing a thesis?

I think you should only write a thesis if you’re genuinely interested in the topic you’re about to write on. I know I really enjoyed doing field work this summer, and writing the thesis has been just looking at the science behind all of what I did over the summer, so it’s been enjoyable to write, and it’s been really interesting because we’re doing something new in this field. I find myself sometimes doing my other homework just so I can get to work on my thesis, that’s the more enjoyable thing.