Evolutionary and Behavioral Effects of Social Interactions
Social interactions and the maintenance of alternative male life histories
Phenotypic variation is a prerequisite for natural selection, but when selection favors a particular phenotype, variation can be quickly eroded. This is a puzzle in evolutionary biology: how is variation maintained in the face of selection on adaptive traits? Social interactions are implicated as a crucial factor in the maintenance of phenotypic variation in some species because the fitness consequences of alternative life history phenotypes are typically mediated by social interactions, and development of alternative phenotypes can be regulated by social factors. We are interested in how social interactions during development and adulthood can affect behavior, morphology, life history, and fitness.
The evolution of socially-cued plasticity​
Phenotypic plasticity, the ability of individuals to alter their phenotype in response to environmental cues, is thought to be widespread. Existing theoretical work on the topic has largely focused on identifying when environmental conditions favor phenotypically plastic strategies over developmentally fixed ones. These models usually consider extrinsic environmental factors (often abiotic) that cue development of irreversible plastic strategies. However, if the environmental cue is a feature of the social environment, phenotypically plastic developmental responses can, by shifting the composition of the population, modify the cue. In doing so, these irreversible plastic responses may compromise the reliability of the social cue as a predictor of future environmental conditions, leading to potentially complex feedbacks between phenotypic plasticity and fitness. The social environment can directly affect development and fitness. However, we do not know whether or how selection favors juveniles that use features of the social environment to cue alternative developmental pathways. Socially-cued anticipatory plasticity (SCAP) is a hypothetical strategy whereby juveniles use social cues to alter their development in an attempt to match their adult phenotype to the social environment they expect to encounter. While intuitively appealing, evolution of such plasticity is a puzzle, because the cue used to determine an individual's strategy (the social environment) can change in response to individuals using that strategy. Can SCAP evolve as a strategy when such feedback occurs? We use individual-based simulation models to answer this question.
Seasonal variation in social environment and male alternative mating strategies
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In many taxa, individuals display discrete variation in both morphology and behavior. However, how these alternative reproductive tactics are maintained in many populations has yet to be adequately explained. It is important to understand how the environment varies to understand how phenotypically plastic individuals may respond. A first step in addressing this question is to describe how behavior and other phenotypes change within a population over time and spatially across populations.
Social determinants of health and fitness across the life course​
Social interactions often occur throughout an individual's life and variation in the social environment at different developmental stages may not equally affects phenotypes. Using a long term data set from the Amboseli Baboon Research Project, we are assessing how early life experience and adult social environment affect lifespan and other phenotypes. In collaboration with the statistics department at Duke University, we are developing new statistical techniques to determine if juvenile social environment determines adult social interactions, or if social environment during these life stages exert independent effects on baboon phenotypes.
Quantitative genetic basis of social traits​
Social traits must be heritable in order to evolve, but the extent to which social traits are heritable is unknown in many species. Using a long term data set from the Amboseli Baboon Research Project, we are working to understand the quantitative genetic basis of two important social traits: the age at which an individual baboon starts grooming and the age at which an individual baboon has it's first antagonistic interaction. Both grooming and agonism are key social behaviors, but the environmental and genetic determinants of these behaviors is unknown. Stay tuned to find what what determines these important social traits!
