國立自然科學博物館

線紋蜻蜓據瞭解只分佈在台南以南的山區、冬天很少看到族群活動'但在台南的崁頭山步道卻發現有意外的行為~動物有群聚的行為、但昆蟲尤其是蜻蜓群聚不只是取暖也是擬態、只有在崁頭山被發現!更有趣的是溫度越低16度以下他的尾巴會往背部彎曲 (早晨7度時甚至成半圓型)若溫度持續低溫發現兩三天都保持在枯藤上'待太陽出來溫度回溫18度以上後尾巴就會伸直'接著振翅飛離覓食! 目前昆蟲研究者也無法解釋'因為全國只有這區域有這種蜻蜓行為甚至只有這條步道'而且樹根有很多條但他們只選擇一條群聚!據瞭解其它地區的線紋蜻蜓皆未發現有此行為...據觀察這很可能是這個族群正在進行(演化論)'群聚(最多發現有48只)不只可以取暖還可以擬態成枯枝枯葉躲避天敵、就類似群聚的斑馬讓獅子無法鎖定目標一樣、因為發現周遭有很多鳥類、牠們卻平安無事'真是生態奇觀.

Line forest-skimmer (cratilla lineata) is understood to be only distributed in the mountains in south of Tainan, and their activities are rarely seen in the winter except for the surprising discovery in Kantou Mountain trail in Tainan. Animals have gathering behaviours but insects, especially dragonflies, do not only gather for warmth but also disguise. It is only found in Mount Kantou! What is more interesting is that when the temperature is as low as below 16 degrees, it would bend its tail to the back (even form half a circle at 7 in the morning). If the temperature stays low, it can stay on a branch for two or three days until the sun comes out and the temperature returns to above 18 degrees, then the tail will be straightened out and it will fly off the branch to seek for food. Up until now, researchers cannot explain why only this type of dragonflies in this area has this type of behaviour, even only on this trail. Besides, there are many branches and they only choose this one. It seems like dragonflies in other areas do not have this behaviour, and it is assumed that this group is enacting a process of evolution where they discover that gathering (currently maximum of 48 found) can not only provide warmth but also disguise them into dead branches and leaves to avoid natural enemies, just as a group of zebras can make it hard for lions to locate their target. There are many birds surrounding them but they stayed safe this way. It is quite the ecological wonder.

器材:TAMORN1800mm/閃燈/ F:3.5-10 /T:250/腳架