Colors as life history traits Insights from the pigment-based coloration of two butterfly species

January 3 – Febuary 28, 2021

Meeting Abstract

S7-4  Wed Jan 6 11:30 – 12:00  Colors as life history traits: Insights from the pigment-based coloration of two butterfly species Morehouse, NI; University of Cincinnati

Animal colors, once thought to evolve strictly on the basis of their semiotic value, are now known to impose often-significant material costs. For example, many red, orange, and yellow avian colors rely on substantial inputs of diet-derived carotenoids. This has led researchers to ask whether color evolution might reflect material tradeoffs between colors and other traits, such as immunocompetence or oxidative stress tolerance. However, mechanistic support for such connections has often been elusive, even in well-studied systems such as avian carotenoid coloration. This may be due in part to life history characteristics of focal taxa, where researchers have often favored the study of income breeders. Income breeders fund the costs of reproduction, including sexually selected colors, via a mix of past and current income, thereby making supply-and-demand connections more challenging to resolve. Here, I discuss insights into the material basis and evolution of bright coloration from two capital breeding butterflies: Pieris rapae and Araschnia levana. In P. rapae, dietary protein limitations during larval development force tradeoffs between pterin-based adult male coloration and a variety of other reproductive and non-reproductive traits. The result is deep integration between color and other life history traits, which helps to explain why these colors have evolved under female choice as indicators of male quality. In contrast, the evolution of ommochrome-based seasonal color polyphenism in A. levana has been shaped not by scarcity, but rather by a need to cope with the toxic/hormone suppressant effects of ommochrome precursors. Taken together, these case studies highlight the utility of studying capital breeders when investigating the evolutionary consequences of the material basis for animal colors.

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