Many animals are marked with conspicuous circular features often called ＇eyespots＇, which intimidate predators, preventing or halting an attack. It has long been assumed that eyespots work by mimicking the eyes of l...Many animals are marked with conspicuous circular features often called ＇eyespots＇, which intimidate predators, preventing or halting an attack. It has long been assumed that eyespots work by mimicking the eyes of larger animals, but recent experiments have indicated that conspicuousness and contrast is important in eyespot function, and not eye mimicry. We undertake two further experiments to distinguish between the conspicuousness and mimicry hypotheses, by using artificial prey presented to wild avian predators in the field. In experiment 1, we test if eyespot effectiveness depends on the marking shape （bar or circle） and arrangement （eye-like and non-eye-like positions）. We find no difference between shapes or arrangement; all spots were equally effective in scaring birds. In experiment 2, we test if the often yellow and black colors of eyespots mimic the eyes of birds of prey. We find no effect of shape, and no advantage to yellow and black spots over non-eye-like but equally conspicuous colors. The consistent finding is that eyespot function lies in being a conspicuous signal to predators, and not necessarily due to eye mimicry [ Current Zoology 55 （5） ： 319 - 326, 2009].展开更多
基金supported by a Research Fellowship from Girton College,Cambridge,and a Royal Society Research Grantby an Association for the Study of Animal Behaviour Undergraduate Project Scholarship+1 种基金by a Nuffield Undergraduate Science Bursaryby a Department of Zoology J Arthur Ramsay Trust Fund
文摘Many animals are marked with conspicuous circular features often called ＇eyespots＇, which intimidate predators, preventing or halting an attack. It has long been assumed that eyespots work by mimicking the eyes of larger animals, but recent experiments have indicated that conspicuousness and contrast is important in eyespot function, and not eye mimicry. We undertake two further experiments to distinguish between the conspicuousness and mimicry hypotheses, by using artificial prey presented to wild avian predators in the field. In experiment 1, we test if eyespot effectiveness depends on the marking shape （bar or circle） and arrangement （eye-like and non-eye-like positions）. We find no difference between shapes or arrangement; all spots were equally effective in scaring birds. In experiment 2, we test if the often yellow and black colors of eyespots mimic the eyes of birds of prey. We find no effect of shape, and no advantage to yellow and black spots over non-eye-like but equally conspicuous colors. The consistent finding is that eyespot function lies in being a conspicuous signal to predators, and not necessarily due to eye mimicry [ Current Zoology 55 （5） ： 319 - 326, 2009].
