利用長期觀測的資料驗證支持擬態生物學中的基礎假設
photo from Lorquin's admiral (wiki)
photo from Adelpha californica (wiki)
標題：A test of fundamental questions in mimicry theory using long-term datasets
摘要
Since the phenomenon of mimicry was first described by Bates in 1862 it has become one of the foundational examples of adaptive evolution. Numerous subcategories of mimicry and dozens of hypotheses pertaining to its evolution and maintenance have been proposed. Many of these hypotheses, however, are difficult to test in experimental settings, and data from natural observations are often inadequate. Here we use data from a long-term survey of butterfly presence and abundance to test several hypotheses pertaining to Batesian and female-limited polymorphic mimicry (FPM; a special case of Batesian mimicry). We found strong evidence that models outnumber mimics in both mimicry systems, but no evidence for an increase in relative abundance of FPM mimics to their Batesian counterparts. Tests of the early-emergence/model first hypothesis showed strong evidence that the Batesian mimic routinely emerges after the model, while emergence timing in the FPM system was site specific, suggesting that other ecological factors are at play. These results demonstrate the importance of long-term field observations for testing evolutionary and ecological hypotheses.
這個研究透過累積十年的蝴蝶記錄資料來探討這個問題，資料記錄的地點在北美洲，分別是Gates Canyon、Washington與Lang Crossing（詳細資訊見butterfly.ucdavis.edu），記錄的時間大約是每14天一次，累積了1999-2010間的資料。
他們想要討論的問題在於如果貝氏擬態的mimic太多，會導致整個系統的保護作用降低或失效，因此mimic絕對不能比model還多，因此一個可能性就是「model在自然界中絕對數量比mimic多」，另一個可能性是如果mimic只有其中一個性別擬態，那麼相對來說mimic的數量也會減少，因此他們選了兩個系統，其中一個是代表貝氏擬態的系統，Adelpha californica (model)與Limenitis lorquinii (mimic)（見上圖），另一個是雌性擬態的系統（見下圖）。
結果顯示兩個系統中，model的數量都遠多於mimic。發生的時序上來說，貝氏擬態的mimic出現時序都晚於其model，而雌性擬態的物種出現則局現在某幾個地方，可能有其他的生態因子限制其分佈。
photo from Euphydryas chalcedona (wikimedia) (left) and Butterflies of America (right)
photo from Wild Utah (left) and Butterflies of America (right)
上排是model，Euphydryas chalcedona，是一個有兩型的物種；下排是mimic，Chlosyne palla，是一個雌性多態型的物種，作者認為左下的黑色型擬態左上的黑色型
這個例子是個以溫帶物種來說明的例子，但在熱帶/亞熱帶區域卻總有些例子是相反的（mimic早於model出現），雖然已經有些行為學上的證據支持這樣的現象發生，若有可能的話，透過類似的觀察與紀錄累積，或許熱帶/亞熱帶區域的結果會不一樣。（第一個問題：去哪找人合作觀察十年？）
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