Natural selection, adaptive plasticity, and avian malaria

Abstract

Plastic traits, such as variable behavior and physiology, are front‐line components of adaptive responses to dynamic challenges. For example, plastic responses to parasites and pathogens are essential to both resistance and tolerance of infection; yet, these responses can also be associated with high costs, including immunopathology, loss of homeostasis, and expended resources. Because of these costs and benefits, we expect that natural selection will continue to shape and refine plastic responses to parasites. Understanding the ways that selection is shaping plastic traits could help explain differences among individuals, populations, and species, but adaptive plasticity complicates the application of classical approaches to measuring natural selection. In this talk, I will describe our work aimed at understanding how selection acts on plastic responses to infection in a free‐ranging population of red‐winged blackbirds with a remarkably high prevalence (95%) of haemosporidian parasites (e.g., Plasmodium and Haemoproteus). Overall, our findings point to fitness costs of chronic infection that blackbirds tolerate through induction of adaptive plasticity. Our work illustrates both the benefits and perils of applying classical evolutionary approaches to understanding the adaptive significance of individual variation in plastic traits. More broadly, with an evolutionary perspective in the study of plastic traits involved with resistance and tolerance of infection, we can better appreciate the dynamic nature of host‐parasite interactions.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.