Department of Biological and Environmental Science, Centre of Excellence in Evolutionary Research, University of Jyväskylä, PO Box 35, FI-40014 University of Jyväskylä, Finland.
Proc Biol Sci. 2012 Jun 7;279(1736):2099-105. doi: 10.1098/rspb.2011.2360. Epub 2012 Jan 11.
Müllerian mimicry describes the close resemblance between aposematic prey species; it is thought to be beneficial because sharing a warning signal decreases the mortality caused by sampling by inexperienced predators learning to avoid the signal. It has been hypothesized that selection for mimicry is strongest in multi-species prey communities where predators are more prone to misidentify the prey than in simple communities. In this study, wild great tits (Parus major) foraged from either simple (few prey appearances) or complex (several prey appearances) artificial prey communities where a specific model prey was always present. Owing to slower learning, the model did suffer higher mortality in complex communities when the birds were inexperienced. However, in a subsequent generalization test to potential mimics of the model prey (a continuum of signal accuracy), only birds that had foraged from simple communities selected against inaccurate mimics. Therefore, accurate mimicry is more likely to evolve in simple communities even though predator avoidance learning is slower in complex communities. For mimicry to evolve, prey species must have a common predator; the effective community consists of the predator's diet. In diverse environments, the limited diets of specialist predators could create 'simple community pockets' where accurate mimicry is selected for.
缪勒拟态描述了警戒性猎物物种之间的密切相似性；它被认为是有益的，因为共享警告信号可以降低因经验不足的捕食者学习避免信号而导致的死亡率。有人假设，在多物种猎物群落中，选择拟态的压力最强，因为在这些群落中，捕食者更容易错误识别猎物，而在简单的群落中则不会。在这项研究中，野生大山雀（Parus major）从简单（猎物出现次数较少）或复杂（猎物出现次数较多）的人工猎物群落中觅食，其中总是存在特定的模型猎物。由于学习速度较慢，当鸟类没有经验时，模型在复杂的群落中确实会遭受更高的死亡率。然而，在随后对模型猎物的潜在拟态（信号准确性的连续体）进行的泛化测试中，只有从简单群落觅食的鸟类会选择不准确的拟态。因此，即使在复杂的群落中，捕食者回避学习速度较慢，简单的群落中也更有可能进化出准确的拟态。为了使拟态进化，猎物物种必须有一个共同的捕食者；有效的群落由捕食者的饮食组成。在多样化的环境中，专门捕食者有限的饮食可能会创造出“简单的社区口袋”，在这些社区中，准确的拟态会被选择。
