Ehrenfeld Award 2026

Winner: Lorraine Perez Beauchamp

I am a master’s student from the Ecology and Evolutionary Biology Department at the University of Connecticut. I did my bachelor’s degree in Biology at the same institution, which is when I discovered my passion for urban ecology in Sarah Knutie’s lab (who is now my graduate advisor). 

I am broadly interested in the intersection between urban and disease ecology, with the goal of better understanding how urban living affects host-parasite interactions. For my research, I explore how urbanization in the Galápagos Islands influences the disease risk of Darwin’s finches against their vampire flies (Philornis downsi). Interestingly, urban finches are less affected by vampire flies compared to non-urban finches, but the mechanism mediating this pattern is not well understood. During my ESA presentation, I presented findings from my undergraduate and master’s theses exploring whether 1) urban finches reduce their parasite abundance with insecticidal cigarette butts, and 2) whether adult flies visit urban nests less frequently compared to non-urban nests.

Accepted Abstract: Exploring mechanisms mediating the effect of urbanization on Darwin’s finches and their invasive parasites

Human activity has facilitated the introduction of novel species, including parasites, to new areas. Hosts from island ecosystems are particularly vulnerable to the effects of introduced parasites because of their small population sizes and lack of native parasite exposure. Over the past few decades, several novel parasites of birds have been introduced to the Galapagos Islands. For example, the larval stage of the invasive avian vampire fly (Philornis downsi) causes up to 100% mortality in endemic land bird species, including Darwin’s finches. However, from 2019-2025, we found that urban nestlings are less affected by vampire flies than non-urban nestlings, in part, because they have fewer parasites in their nests. Since 2019, we have not found evidence to support the potential explanations that: 1) urban areas have a smaller adult fly population to infest nests than non-urban areas, or 2) urban nestlings are more immunologically resistant to the parasites than non-urban nestlings.

Since urban finches incorporate human debris into their nests, an alternative explanation is that urban finches incorporate insecticidal cigarette butts into their nests to kill flies. We tested this idea by experimentally exposing larval flies to cigarette tobacco in the lab and found that tobacco-treated flies had lower survival than control flies. However, after dissecting nests for evidence of cigarette material, we found that finches do not incorporate enough cigarette butts into their nests to effectively reduce parasite survival. More recently, our video footage within nests containing hatchling finches revealed that flies visit non-urban nests more than urban nests, which may explain differences in resulting parasite abundances across areas.The potential mechanism underlying differences in fly visitation rates across areas will be discussed.
Over 15 years of research across populations, species, and islands has shown that avian vampire flies have devastating effects on the survival of Darwin’s finches living in non-urban areas. However, our research demonstrates the need for studying the effect of environmental factors, including human activity, on host-parasite interactions. Furthermore, our work highlights the importance of studying both host and parasite ecology to understand mechanisms underlying spatial differences in their interactions.