[Article] Metriorrhynchus屬（鞘翅目：紅螢科）的擬態斑紋之演化歷史

原文標題：Evolution of mimicry patterns in Metriorrhynchus (Coleoptera: Lycidae): The history of dispersal and speciation in Southeast Asia

摘要 [原文網址]

The concept of Müllerian mimicry suggests convergent evolution to an intermediate pattern and does not predict polymorphism in mimicry rings. We examined the evolution of mimicry patterns and the order of divergence of various factors, including the role of aposematic patterns in speciation, in a clade of net-winged beetles with a robust phylogeny that suggests that they dispersed from the Australian to Asian plate. We found strong evidence for the evolution of mimicry via advergence inMetriorrhynchus because older patterns are represented in the Oriental region within more than 100 species of lycids from several lineages. Advergence was likely the cause of the observed intraspecific polymorphism in contrast to the predicted universal monomorphism. Polymorphism was found in populations of two species in Sumatra and Borneo and in populations fine-tuned to subtle variants in various habitats. The advergence is likely to be based on the small population sizes of immigrants. The differences in population sizes result in much higher benefits for dispersing species than native populations. Speciation was trigged by the divergence in aposematic coloration, and the genetic differences accumulated slowly during incomplete isolation. We assumed that the differentiation in genitalia through sexual selection ultimately reinforced speciation initiated by the shift between mimicry patterns.

紅螢是個全世界分布的東西，主要分布在熱帶與亞熱帶，很多的觀察都指出紅螢似乎是個很有用的樣式，諸如一些鱗翅目（如榕蛾）、半翅目（某些星椿）與鞘翅目（如蓬萊紅天牛、金花蟲），都可以看到像是紅螢的影子。紅螢的防禦來自於自體分泌的吡嗪類化合物（pyrazines)與紅螢酸（lycidic acid），這類物質對於大部分的捕食者而言是很有效的避忌物。

這篇文章主要就是在討論紅螢科Metriorrhynchus屬的擬態斑紋的演化，配合生物地理事件加上定年，就可以知道每個節上發生的地理事件，然後利用這些資料推斷擬態的斑紋是否促進種化與限制了分布。這個屬主要的斑紋如下圖，擬態的斑紋就是只1.2/3.4這兩種中段是紅尾段是藍的樣式。利用了系統發生學的方法與定年後，發現擬態的種與其姊妹種（如3.4/5）的遺傳差距其實不高，顯示擬態的斑紋可能促進了族群的分化，而不同區域的擬態群可能來自多態型的分化。



其實這樣的介紹有點太簡單，只把一些比較重要的重點節錄出來，文內討論了種化、斑紋演化、生殖器構造等等，用了很多不同的面象討論這個屬的種化歷程，若要了解的更詳細，還是請看內文吧！