巧奪天工的穆氏擬態：斑紋最佳相似度來自表型的細緻改變
photo from Bernard D'Abrera
摘要
1.Müllerian mimicry between chemically defended preys is a textbook example of natural selection favouring phenotypic convergence onto a shared warning signal. Studies of mimicry have concentrated on deciphering the ecological and genetic underpinnings of dramatic switches in mimicry association, producing a well-known mosaic distribution of mimicry patterns across geography. However, little is known about the accuracy of resemblance between natural co-mimics when the local phenotypic optimum varies.
2.In this study, using analyses of wing shape, pattern and hue, we quantify multimodal phenotypic similarity between butterfly co-mimics sharing the so-called postman pattern in different localities with varying species composition.
3.We show that subtle but consistent variation between populations of the localised species, Heliconius timareta thelxinoe, enhance resemblance to the abundant co-mimics which drive the mimicry in each locality.
4.Those results suggest that rarer co-mimics track the changes in the phenotypic optimum caused by gradual changes in the composition of the mimicry community, providing insights into the process by which intra-specific diversity of mimetic pattern may arise. Furthermore, our results suggest a multimodal evolution of similarity, with coordinated convergence in different features of the phenotype such as wing outline, pattern and hue.
5.Finally, multilocus genotyping allows estimating local hybridization rates between H. timareta and co-mimic H. melpomene in different populations, raising the hypothesis that mimicry refinement between closely-related co-mimics may be enhanced by adaptive introgression at loci modifying the accuracy of resemblance.
無論從哪個角度來說，穆氏擬態群內的斑紋應該要越相似越好，如果有個體長的突然與大家不一樣，可能就會被天擇排擠消失，也或許有機會獨樹一格（低機率），雖然人類視覺角度來看，穆氏擬態群的每個物種或個體都十分相似，但之前已經有研究指出不同種間的相似斑紋來源可能是透過不同的基因調控來的，若是如此，自然界中展現出來的表型看起來雖然一致，但會不會是在某個可接受的誤差範圍內呢？
photo from content
此圖說明參與「郵差」擬態型的物種
這也是個model強烈的主導mimic的斑紋變化，在天擇的作用下，mimic透過細微的改變趨近model的一證據。（自然界中的霸凌？）
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