Olof Leimar, Birgitta S. Tullberg, and James Mallet
- Published in print:
- 2013
- Published Online:
- December 2013
- ISBN:
- 9780199595372
- eISBN:
- 9780191774799
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199595372.003.0016
- Subject:
- Biology, Evolutionary Biology / Genetics
Mimicry and aposematism are phenomena for which the concept of an adaptive landscape has proven helpful. In mimicry evolution, members of a species become similar in appearance to an aposematic model ...
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Mimicry and aposematism are phenomena for which the concept of an adaptive landscape has proven helpful. In mimicry evolution, members of a species become similar in appearance to an aposematic model species and thereby gain increased protection from predation. A traditional suggestion is that mimicry evolves in a two-step process, where a large mutation first achieves approximate similarity to the model, after which smaller changes improve the likeness. In terms of adaptive landscapes, the process entails a mutational leap from the adaptive peak of the mimic-to-be, to somewhere on the slope of a higher, more protective peak of the model, thus crossing a fitness valley, followed by a series of smaller modifications climbing the higher peak. Alternatively, evolutionary forces other than mimicry, including genetic drift, may modify the appearance of mimics-to-be, perhaps exploring different peaks of an adaptive landscape in a shifting balance process, and fortuitously bringing about sufficient resemblance to a model to start off mimicry evolution. This chapter reviews and evaluates these ideas. It emphasizes the possibility that mimicry is initiated by a mutation that causes prey to acquire a trait that is used by predators as a feature to categorize potential prey as unsuitable. The theory that species gain entry to mimicry through feature saltation can help in formulating scenarios of the sequence of events during mimicry evolution and in reconstructing an initial mimetic appearance for important examples of mimicry.Less
Mimicry and aposematism are phenomena for which the concept of an adaptive landscape has proven helpful. In mimicry evolution, members of a species become similar in appearance to an aposematic model species and thereby gain increased protection from predation. A traditional suggestion is that mimicry evolves in a two-step process, where a large mutation first achieves approximate similarity to the model, after which smaller changes improve the likeness. In terms of adaptive landscapes, the process entails a mutational leap from the adaptive peak of the mimic-to-be, to somewhere on the slope of a higher, more protective peak of the model, thus crossing a fitness valley, followed by a series of smaller modifications climbing the higher peak. Alternatively, evolutionary forces other than mimicry, including genetic drift, may modify the appearance of mimics-to-be, perhaps exploring different peaks of an adaptive landscape in a shifting balance process, and fortuitously bringing about sufficient resemblance to a model to start off mimicry evolution. This chapter reviews and evaluates these ideas. It emphasizes the possibility that mimicry is initiated by a mutation that causes prey to acquire a trait that is used by predators as a feature to categorize potential prey as unsuitable. The theory that species gain entry to mimicry through feature saltation can help in formulating scenarios of the sequence of events during mimicry evolution and in reconstructing an initial mimetic appearance for important examples of mimicry.
