Meeting Abstract

P3.53  Sunday, Jan. 6  Quantifying the variation in antipredator chemotypes among populations of western toads (Bufo boreas) MARION, ZH*; PAULY, GB; FORDYCE, JA; Univ. of Tennessee, Knoxville; Nat. Hist. Mus. of Los Angeles; Univ. of Tennessee, Knoxville zmarion@utk.edu

The majority of chemical research on antipredator adaptations has concentrated on the effects that individual chemical compounds have on ecological and evolutionary interactions. Yet many, if not most, chemical defenses consist of complex blends of multiple interacting compounds that vary qualitatively (i.e, molecular structure) and quantitatively (i.e., concentrations or total amounts) in effectiveness. Unfortunately, the multivariate nature of complex integrated phenotypes are often ignored, especially within the chemical defense literature. In this study, we collected parotid secretions from individuals from multiple populations of western toads in the Bufo boreas species complex across their range and analyzed their defensive chemotypes via HPLC. We then applied multivariate statistical methods traditionally used in the analysis of ecological community composition and species diversity to document the variation and diversity of defensive chemicals within and among toad populations. We show that substantial variation exists both in the total quantitative amount of cardiac steroids (bufadienolides) in toads but also in terms of chemical diversity, especially among calling and non-calling populations.