Posted: Feb 13, 2011 1:35 am
by Calilasseia
And in the case of cryptically coloured butterflies, enough work has been published referring to Turing morphogenesis (which, incidentally, is modelled by systems of differential equations) illustrating that the relevant patterns can be produced in a mechanistic fashion, to nail once and for all the idea that magic is needed for this. I have several papers on the application of Turing morphogenesis (which relies upon differential flows in tissues of activator and suppressor morphogens) in Papilio dardanus alone, a butterfly that has been extensively researched courtesy of the fact that females exhibit a range of mimetic patterns, which differ according to geographic location and the presence of different model species. In some parts of the range of Papilio dardanus, the females are mimics of butterflies such as various Euploea species, in others, they are mimics of Danaus chrysippus, in other parts of the range, they are mimics of various Acraea species, all of the model species in question being aposematically coloured species. These model species sequester phytotoxins from larval foodplants as a chemical defence, advertise this fact to birds using aposematic colouration, and the females of Papilio dardanus mimic these other butterflies. Indeed, it was a late member of my very own Entomology Society, who, after conducting thousands of trial matings and observing the outcomes, alighted upon the fact that the mimetic wing patterns in Papilio dardanus are controlled by a polygene cluster. That polygene cluster almost certainly includes signal transduction genes coding for upregulators and downregulators of a range of substances involved in wing pattern formation.

Likewise, the same mechanism (Turing morphogenesis) accounts for the appearance of eye spots in Bicyclus anyana (again I have relevant papers), and is almost certainly implicated in the wing patterns of leaf mimics such as the Indian Kallima species (of which Kallima paralekta is merely the best known), or the South American Anaea leaf mimics, or, most spectacularly of all, this beast, which rejoices in the wonderful name of Coenophlebia archidona :

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