Covetable Corpses and Plastic Beetles - The Socioecological Behavior of Burying Beetles

Abstract

Among-individual variation in behavioral plasticity-the modification of behavior in response to changes in environment experienced by individuals-is increasingly recognized as an important, but relatively poorly understood, feature of organisms that facilitates adaptation to environmental change. It is expected to evolve when there is rapidly fluctuating or directional environmental change during the lifetime of individuals. This is particularly likely to occur in the context of reproductive behaviors, when the outcomes of unpredictable social interactions with other individuals during mating and parental care determine how selection acts on males and females and mating systems evolve. To better understand patterns of mating and parental care and organismal adaptation to environmental change, we need to know why there is so much variation in behavioral plasticity between and within species. Here we address this question using burying beetles as a model. Burying beetles have unusually variable, facultatively expressed, modes of parental care and variation between the sexes and among individuals in the plasticity of reproductive behaviors. We present evidence to show that variation in male plasticity of mating behavior is a key driver of the evolution of patterns of parental care in Nicrophorus vespilloides burying beetles. More generally, we conclude that behavioral plasticity in burying beetles, and likely other taxa, has evolved as a consequence of a resource requirement bottle-neck (niche specialization) in combination with highly unpredictable availability of such suitable resources and the social unpredictability that arises as a result: constraint is the mother of plastic invention.