Tale of three toxins: How butterflies respond to anthropogenic change

Abstract

Why do some animals persist while others perish when challenged with new and rapidly changing environments? This question is central not only for preserving the diversity of life in a world increasingly impacted by humans, but also for understanding how organisms survived, diversified, or went extinct in the past. The main goal of my dissertation was to combine ecotoxicological and evolutionary approaches to understand why some animals survive (and others do not) when challenged with novel anthropogenic pollutants. To do so, I examined how butterflies vary in response to pollution over many scales of genetic variation, from differences between individuals, to differences between populations within a species, to comparing species. I also evaluated how plastic traits are in their response to toxic environments. I chose three pollutants – an insecticide, a heavy metal, and road salt – to answer specific questions about the interaction between genetic variation and plasticity. Throughout, I assessed if and how butterflies’ survival and life histories are affected by toxin exposure. Overall, I found appreciable amounts of genetic and plastic variation in response to the three toxins, suggesting that butterfly populations may be resilient to low levels of toxic threats in the short term.