Reduced predation risk for melanistic pygmy grasshoppers in post‐fire environments

Ecology and Evolution

Einat Karpestam¹  Sami Merilaita² 

[1] Ecology and Evolution in Microbial Model Systems, EEMiS, School of Natural Sciences, Linnaeus University, Kalmar, Sweden;Environmental and Marine Biology, Åbo Akademi University, Turku, Finland

关键词: Adaptation;    camouflage;    crypsis;    evolution;    fire melanism;    masquerade;    predation;   

DOI  :  10.1002/ece3.338

来源: Wiley

【 摘 要 】

Abstract

The existence of melanistic (black) color forms in many species represents interesting model systems that have played important roles for our understanding of selective processes, evolution of adaptations, and the maintenance of variation. A recent study reported on rapid evolutionary shifts in frequencies of the melanistic forms in replicated populations of Tetrix subulata pygmy grasshoppers; the incidence of the melanistic form was higher in recently burned areas with backgrounds blackened by fire than in nonburned areas, and it declined over time in postfire environments. Here, we tested the hypothesis that the frequency shifts of the black color variant were driven, at least in part, by changes in the selective regime imposed by visual predators. To study detectability of the melanistic form, we presented human “predators” with images of black grasshoppers and samples of the natural habitat on computer screens. We demonstrate that the protective value of black coloration differs between burnt and nonburnt environments and gradually increases in habitats that have been more blackened by fire. These findings support the notion that a black color pattern provides improved protection from visually oriented predators against blackened backgrounds and implicate camouflage and predation as important drivers of fire melanism in pygmy grasshoppers.

【 授权许可】

Unknown   
© 2012 The Authors. Published by Blackwell Publishing Ltd. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.