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An eyespot (sometimes ocellus) is an eye-like marking. They are found on butterflies, reptiles, felids, birds and fish. Eyespots may be a form of mimicry in which a spot on the body of an animal resembles an eye of a different animal to deceive potential predator or prey species; to draw a predator's attention away from the most vulnerable body parts; or to appear as an inedible or even dangerous animal. In larger animals, eyespots may play a role in intraspecies communication or courtship – the most well-known example is probably the eyespots on a peacock's display feathers. The eye-like markings in some butterflies and moths, like the ''Bicyclus anynana,'' and certain other insects, as well as the Sunbittern (a bird) do not seem to serve only a mimicry function. In some other cases, the evolutionary function of such spots is also not understood. There is evidence that eyespots in butterflies are antipredator adaptations, either in deimatic displays to distract, startle or scare off predators, or to deflect attacks away from vital body parts.〔http://www.sify.com/news/female-butterflies-chase-males-when-it-s-cool-news-international-lbhpahdfgff.html〕 Butterfly eyespots may also play a role in mate recognition and sexual selection, playing a similar role to the eyespots found on larger organisms mentioned above. Pattern formation of concentric spots is probably less complex than the conspicuous eyespots might suggest; eyespots may simply be morphogenetic "spandrels", not necessarily adaptations. ==Evolution of the eyespot at the molecular level== Butterfly eyespots are formed as a result of a morphogenetic signaling center, or organizer called the focus. This signaling center induces its neighboring cells to produce specific pigments which pattern the eyespot. Foci morphology and evolution appears to be the result of an altered regulatory circuit composed of the same patterning mechanisms conserved in insect wing patterning. This altered regulatory circuit is able to pattern both the anterior and posterior eyespots independent of the anterior/posterior wing compartmentalization restrictions.〔 Breaking the highly conserved compartmentalization restrictions put forth by insect wing patterning, by redeployment of early developmental signaling sources like the canonical hedgehog (Hh) pathway, Distalless (Dll), and engrailed (en), this altered regulatory circuit is able to pattern both the anterior and posterior eyespots independent of the A/P compartmentalization restrictions through increased localized levels of hh signaling.〔〔〔 Increased hh signaling raises expression of its receptor ptc and transcription factor.〔 Normally, in the fruit-fly ''Drosophila'', engrailed(en) acts in the posterior compartment to restrict ptc and ci expression to the anterior compartment by repressing transcription of ci, thereby preventing expression of ptc. However, This rogue expression of ptc and ci seen in the posterior compartment of some butterfly wing disks, is an indication that during the evolution of eyespots, there was a divergence in the repression or expression of these genes from that of drosophila.〔 From an evo-devo perspective, understanding the redeployment and plasticity of already existing regulatory mechanisms in butterfly eyespot loci development may give more insight into a fundamental mechanism for the evolution of novelty structures.〔〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Eyespot (mimicry)」の詳細全文を読む スポンサード リンク
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