Not just the sum of its parts: Geographic variation and nonadditive effects of pyrazines in the chemical defence of an aposematic moth.

Autor: Ottocento C; Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.; Department of Biology and Environmental Science, University of Jyväskylä, Jyväskylä, Finland., Winters AE; Department of Biology and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.; College Life and Environmental Sciences, Penryn Campus, University of Exeter, Penryn, UK., Rojas B; Department of Biology and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.; Department of Interdisciplinary Life Sciences, Konrad Lorenz Institute of Ethology, University of Veterinary Medicine Vienna, Vienna, Austria., Mappes J; Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.; Department of Biology and Environmental Science, University of Jyväskylä, Jyväskylä, Finland., Burdfield-Steel E; Department of Biology and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.; Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands.
Jazyk: angličtina
Zdroj: Journal of evolutionary biology [J Evol Biol] 2023 Jul; Vol. 36 (7), pp. 1020-1031. Date of Electronic Publication: 2022 Dec 22.
DOI: 10.1111/jeb.14142
Abstrakt: Chemical defences often vary within and between populations both in quantity and quality, which is puzzling if prey survival is dependent on the strength of the defence. We investigated the within- and between-population variability in chemical defence of the wood tiger moth (Arctia plantaginis). The major components of its defences, SBMP (2-sec-butyl-3-methoxypyrazine) and IBMP (2-isobutyl-3-methoxypyrazine), are volatiles that deter bird attacks. We hypothesized that (1) variation in the chemical defences of male wood tiger moths reflects the local predation pressure; (2) observed differences in quantity and quality of defence among populations have a genetic basis; and (3) increasing concentrations of SBMP and IBMP will elicit greater aversive reactions in predators, with the two pyrazines having an additive effect on predators' avoidance. We found that (1) the chemical defence of wild moths partly reflects local predator selection: high predation pressure populations (Scotland and Georgia) had stronger chemical defences, but not lower variance, than the low-predation populations (Estonia and Finland). (2) Based on the common garden results, both genetic and environmental components seem to influence the strength of chemical defence in moth populations; and (3) IBMP alone did not provide protection against bird predators but worked against bird attacks only when combined with SBMP, and while SBMP was more effective at higher concentrations, IBMP was not. Altogether this suggests that, when it comes to pyrazine concentration, more is not always better, highlighting the importance of testing the efficacy of chemical defence and its components with relevant predators, as extrapolating from chemical data may be less than straightforward.
(© 2022 The Authors. Journal of Evolutionary Biology published by John Wiley & Sons Ltd on behalf of European Society for Evolutionary Biology.)
Databáze: MEDLINE
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