Life history linked to immune investment in developing amphibians.

Laura K Reinert,Urs Stalder,Laurent Bigler,Louise A Rollins-Smith,Richard M Caprioli,Douglas C Woodhams,Klaus Schliep,Pierre Chaurand,Victoria M Vazquez,Brianna A Lam,Sara C Bell,Andreas Hertz

doi:10.1093/conphys/cow025

Abstract

The broad diversity of amphibian developmental strategies has been shaped, in part, by pathogen pressure, yet trade-offs between the rate of larval development and immune investment remain poorly understood. The expression of antimicrobial peptides (AMPs) in skin secretions is a crucial defense against emerging amphibian pathogens and can also indirectly affect host defense by influencing the composition of skin microbiota. We examined the constitutive or induced expression of AMPs in 17 species at multiple life-history stages. We found that AMP defenses in tadpoles of species with short larval periods (fast pace of life) were reduced in comparison with species that overwinter as tadpoles and grow to a large size. A complete set of defensive peptides emerged soon after metamorphosis. These findings support the hypothesis that species with a slow pace of life invest energy in AMP production to resist potential pathogens encountered during the long larval period, whereas species with a fast pace of life trade this investment in defense for more rapid growth and development.

Highlights

Recent ecological theory suggests that trade-offs exist between host defenses and pace of life (Martin et al, 2007; Previtali et al, 2012; Sandmeier and Tracy, 2014; Sears et al, 2015)
We found that antimicrobial peptides (AMPs) defenses in tadpoles of species with short larval periods were reduced in comparison with species that overwinter as tadpoles and grow to a large size
A complete set of defensive peptides emerged soon after metamorphosis. These findings support the hypothesis that species with a slow pace of life invest energy in AMP production to resist potential pathogens encountered during the long larval period, whereas species with a fast pace of life trade this investment in defense for more rapid growth and development

Summary

Introduction

Recent ecological theory suggests that trade-offs exist between host defenses and pace of life (Martin et al, 2007; Previtali et al, 2012; Sandmeier and Tracy, 2014; Sears et al, 2015). Amphibians with a fast pace of life are more likely to use. Behavioural defenses against parasitic trematodes than slow pace-of-life species, and they appear to invest less in costly immune defenses that would provide infection tolerance (Sears et al, 2015). We examine an innate immune defense of amphibians, antimicrobial skin peptides, in relation to amphibian life history and pace of life. We hypothesized that slow pace-of-life species would produce and secrete effective AMPs during the larval period, whereas fast pace-of-life species would not

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Conclusion