The Mechanism for Mimicry: Instant Biosemiotic Selection or Gradual Darwinian Fine-Tuning Selection?
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The Mechanism for Mimicry: Instant Biosemiotic Selection or Gradual Darwinian Fine-Tuning Selection? V. N. Alexander 1,2 Received: 10 January 2018 / Accepted: 8 February 2019/ # Springer Nature B.V. 2019
Abstract Biological mimicry is regarded by many as a textbook illustration of Darwin’s idea of evolution by random mutation followed by differential selection of reproductively fit specimens, resulting in gradual phenotypic change in a population. In this paper, I argue that some cases of so-called mimicry are probably merely look-a-likes and do not gain an advantage due to their similarity in appearance to something else. In cases where a similar appearance does provide a benefit, I argue that it is possible that these forms of mimicry were created in a single generation. An interpretive response to an appearance as a sign can make a new structure perform drastically differently in an environment. In such cases, Darwin’s natural selection mechanism only helps to explain gradual the spread of these new forms, not the creation of them. I argue that biosemiosis should be regarded as a much more powerful mechanism for affecting evolutionary trajectories than the gradualist view allows. I focus on two cases of butterfly mimicry: the Viceroy (Nymphalidae: Limenitis archippus) and Monarch (Nymphalidae: Danaus plexippus) butterflies, supposed Müllerian mimics, and deadleaf mimic butterflies (Kallima). Keywords Saltationism . Turing patterns . Mimicry . Pattern formation . Genus Kallima .
Mimicry skepticism . H. F. Nijhout
* V. N. Alexander [email protected]
1
Dactyl Foundation, 64 Grand Street, New York, NY 10013, USA
2
Fulbright Specialist Program, U.S. Department of State, Bureau of Educational and Cultural Affairs, Washington, D.C., USA
Alexander V.N.
Introduction There is no reason to suppose that a striking similarity in appearance in nature necessarily serves a function. The fact that a beetle’s posterior can appear, to us, to mimic the smile of a person with poor dental hygiene (Fig. 1) has no bearing on whether or not it has more offspring than its competitors. Sometimes such forms appear by chance, serve no purpose, and yet persist. Ever since Gould and Lewontin (1979) critiqued unwarranted Panglossian interpretations of nature’s forms, researchers have become more careful to avoid finding function where there is none. Nevertheless, because certain forms of mimicry were labeled as such long ago (e.g. in Wickler 1968), the designation, persisting now on inertia alone, may inaccurately imply that the organism considered a mimic gains an advantage due to its similarity to a model. Until strong evidence is established that the similarity serves a purpose, it would be more correct to call these organisms Blook-a-likes.^ Many studies are published every year describing the behavior of organisms which appear, to a researcher, to be significantly fooled by some case of mimicry. As the standard of statistical significance as defined by leading neo-Darwinist R. A. Fisher in 1925 may be as low as 5% better than
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