Meeting Abstract

92.4  Monday, Jan. 6 14:15  Characterizing the variation of multivariate chemical defenses in fireflies: a novel approach for chemical ecology MARION, ZH*; TESTER, A; FORDYCE, JA; FITZPATRICK, B; Univ. of Tennessee, Knoxville; Univ. of Tennessee, Knoxville; Univ. of Tennessee, Knoxville; Univ. of Tennessee, Knoxville zmarion@utk.edu

Throughout their evolutionary histories, organisms have evolved complex traits that defend against consumers. These phenotypes consist of multiple, subsidiary traits that behave as a single integrated unit, with individual components that are better suited for some predators than others, or that are differentially expressed at different stages of ontogeny. Closely related populations or species may employ qualitatively and quantitatively different defense strategies because of chance or from past histories in different environments. Chemically-mediated defenses are no exception, but historically, chemical ecologists have often been guilty of ignoring the qualitative variation as either unimportant or analytically intractable, instead focusing on the total amount or concentration of a particular functional class of molecules. In this study, we used LC-MS to explore the defensive chemotypes of multiple populations of several species of North American fireflies (Coleoptera: Lampyridae). The complexity of firefly chemical phenotypes was characterized as the diversity—or effective number—of distinct compounds making up an individual’s cocktail of chemical defenses, while taking relative amounts into account. We demonstrate that there is substantial chemical variation both within and among populations and species, as well as alternative life-history strategies. We also show how our unified, hierarchical view of complexity and diversity suggests the use of analytical methods developed in population genetics and community ecology to characterize complex phenotypes, and helps place questions about the evolution of complexity in a population/community context.