Meeting Abstract

31.5  Friday, Jan. 4  Complex interplay of body condition, life-history, and prevailing environment shape immune defenses of garter snakes in the wild PALACIOS, MG; CUNNICK, J; BRONIKOWSKI, AM*; Iowa State University abroniko@iastate.edu

Evidence for links between ecology, immune function, and life-history strategy remains contradictory; especially regarding the ‘pace-of-life’ ecoimmunology hypothesis that proposes that fast-living organisms should invest more in innate immune defenses and less so in adaptive defenses compared to slow-living ones. Some support for this hypothesis has been found in two life-history ecotypes of the garter snake Thamnophis elegans: fast-living individuals show higher levels of three innate immune indices compared to slow-living ones. Here we assess the complementary prediction that slow-living individuals should in turn show stronger adaptive defenses. We also tested the alternative hypothesis that differences in immune defense are the result of contrasting environmental conditions currently faced by the organisms. This ‘environmental’ hypothesis predicts the opposite pattern for the garter snake system: slow-living individuals should show lower levels of immune defenses (both innate and adaptive) compared to fast-living ones given the harsher environmental conditions (lower temperature, lower and less predictable food availability, and presence of trematode parasites) they face in their habitats. In vitro B- and T-lymphocyte proliferation responses were on average higher in slow-living snakes, opposing the ‘pace-of-life’ and supporting the ‘environmental’ hypothesis. Nevertheless, our results do not negate an influence of life-history on immune defenses: while proliferation of B- and T- lymphocytes increased with increasing body condition in slow-living snakes, the opposite relationship was found in fast-living ones.