Microbe mayhem: The effects of using carbaryl on the microbiome of Purple Martins
Stephanie Gaspar, University of Central Florida
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Purple Martins are migratory insectivores that winter in South America and travel north during their breeding season. With such widespread migration patterns throughout North America and the ability to reduce potential agricultural pests, they originally caught the interest of Native Americans and were provided gourds to nest in millennia ago. Modern Purple Martin landlords have continued interacting with this unique species and have been critical in providing housing during the nestling season. In recent times, populations have decreased and conservation efforts have become key to their survival. The eastern subspecies of Purple Martins are one of the few bird species that have completely shifted their nesting behavior in response to humans and rely on them for yearly support. Landlords employ various methods to manage them during this important time. Once chicks hatch, it becomes apparent that Purple Martins harbor haematophagous ectoparasites such as mites, ticks and fleas. In an effort to reduce mite loads, many landlords use a commonly used garden pesticide, Sevin, in the artificial gourds. Currently, no standardized method or amount is used, and landlords may administer various levels to nests throughout the season as they see fit. There seems to be a reduction in visible mites, but Sevin has the potential to cause unseen harm. Chicks have prolonged exposure to this pesticide from the moment they hatch to when they fledge. It is possible that the active ingredient in Sevin, carbaryl, has a negative effect on their gut microbiome and reduces microbial diversity. Research has shed light on the symbiotic relationship that the gut microbiome plays with its host and how imbalances may affect the health and fitness of many species. Currently, no research has looked at the potential effects of Sevin on the microbiome of Purple Martins. My research will use DNAbased methods to examine microbiome communities in chicks from nests treated with carbaryl versus control nests. Long term exposure to this pesticide could also have negative effects on immunity, fitness, migratory and foraging strategies. This research will better inform citizen scientists and landlords about the possible hazardous effects of Sevin, and encourage better management practices.