Konvergente Farbmusterentwicklungen bei Tagfaltern

摘要

Some major aspects of the phenomenon of mimicry remain puzzling. The evaluation of collected specimens clearly shows the well-known forms of mimicry, i.e. Batesian and Muellerian mimicry, but extensive observations in nature give a more complicated picture, which is not so easily explained by the 'classical' forms of mimicry. In many cases, the obvious similarities of butterflies in their natural habitats do not fit the theories of Batesian or Miillerian mimicry either. The frequency of 'models' and 'mimics' may also not be in accordance with the expectations drawn from theory. During extensive field work in South-East Asia, Africa and South America, an additional and more generalizing theory has been developed to explain patterns of similarity among syntopic and synchronously occuring tropical butterflies. In general, a considerable number of species converge in their overall appearance in flight, but if attacked by birds, the different species try to escape with different patterns of evasive behaviour, flight speed and directional changes, thereby creating a 'confusion group'. This reduces the chances of learning on the part of the predators and prevents a more pronounced convergence on the part of the prey, the palatable butterflies. In some cases wing structures, such as elongated tails, serve to deceive predators. Species of very different systematic position may thus partake in this kind of mimicry grouping without being forced to develop the high degree of conformity typical of Batesian mimicry, as it is sufficient for the similarity to be apparent during rapid and mostly erratic flight. The new results provide a broader view of the mimicry phenomenon and they make the process of fine tuning in the classical forms of mimicry more plausible. The findings in this paper are supported by an extensive array of examples.