Genetic background and thermal environment differentially influence the ontogeny of immune components during early life in an ectothermic vertebrate

PALACIOS, MARIA G.; BRONIKOWSKI, ANNE M.; REDING, DAWN M.; GANGLOFF, ERIC J.

JOURNAL OF ANIMAL ECOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2020

0021-8790

1.         An understudied aspect of vertebrateecoimmunology has been the relative contributions of environmental factors (E),genetic background (G), and their interaction (G × E) in shaping immunedevelopment and function. Environmental temperature is known to affect manyaspects of immune function and alterations in temperature regimes have beenimplicated in emergent disease outbreaks, making it a critical environmentalfactor to study in the context of immune phenotype determinants of wild animals.2.         We assessed the relative influences of environmentaltemperature, genetic background, and their interaction on first-year developmentof innate and adaptive immune defenses of captive-born garter snakes (Thamnophis elegans) using a reciprocal-transplantlaboratory experiment. We used a full-factorial design with snakes from twodivergent life-history ecotypes, which are known to differ in immune functionin their native habitats, raised under conditions mimicking the natural thermalregime ?i.e., warmer and cooler? of each habitat. 3.         Genetic background (ecotype) and thermalregime influenced innate and adaptive immune parameters of snakes, but in animmune-component specific manner. We found some evidence of G × E interactions butno indication of adaptive plasticity with respect to thermal environment. Atthe individual level, the effects of thermal environment on resource allocationdecisions varied between the fast- and the slow-paced life-history ecotypes. Underwarmer conditions, which increased food consumption of individuals in bothecotypes, the former invested mostly in growth, whereas the latter invested moreevenly between growth and immune development. 4.         Overall, immune parameters were highlyflexible, but results suggest that other environmental factors are likely moreimportant than temperature per se indriving the ecotype differences in immunity previously documented in the snakesunder field conditions. Our results also add to the understanding of investmentin immune development and growth during early postnatal life under differentthermal environments. Our finding of immune-component specific patternsstrongly cautions against oversimplification of the highly complex immune systemin ecoimmunological studies. In conjunction, these results deepen ourunderstanding of the degree of immunological flexibility wild animals present,information that is ever more vital in the context of rapid globalenvironmental change.