Vrba Pavel, Konvicka Martin, Nedved Oldrich
Faculty of Science, University of South Bohemia, and Institute of Entomology, Academy of Sciences of the Czech Republic, Ceske Budejovice, Czech Republic.
Cryo Letters. 2012 Jul-Aug;33(4):251-8.
There is strong evidence for a shifting of range boundaries by many temperate butterfly species to higher altitudes and latitudes. Climate change represents a potential threat to mountain fauna. Nevertheless, information on ecophysiological limits of individual species is scarce. We studied the lower thermal limits of four species representing the prevailingly mountain Holarctic butterfly genus Erebia. We measured the cold tolerance of hibernating larvae, namely the supercooling point (SCP) and the lower lethal temperature (LLT). Three mountain species were freeze avoiding, with various levels of SCP (-8 to -22 degree C), and LLT close to SCP. The only exception was lowland E. medusa, whose caterpillars were freeze tolerant with LLT (-21 degree C) slightly below its SCP (-17 degree C). Surprisingly, LLT was highest in the alpine E. tyndarus and lowest in E. medusa inhabiting lower altitudes with higher mean winter temperatures. We explain the observed reversed altitudinal cline in cold hardiness by the buffering function of snow cover in the hibernacula of caterpillars that is strong at high mountains but irregular, unpredictable and thus unreliable in lowlands.
有充分证据表明，许多温带蝴蝶物种的分布范围边界正在向更高海拔和纬度转移。气候变化对山区动物群构成了潜在威胁。然而，关于单个物种生态生理极限的信息却很匮乏。我们研究了代表主要分布在山区的全北区蝴蝶属Erebia的四个物种的低温极限。我们测量了冬眠幼虫的耐寒性，即过冷却点（SCP）和低温致死温度（LLT）。三个山区物种能够避免结冰，其SCP处于不同水平（-8至-22摄氏度），且LLT接近SCP。唯一的例外是低地的美神蛱蝶（E. medusa），其幼虫能够耐受结冰，LLT（-21摄氏度）略低于其SCP（-17摄氏度）。令人惊讶的是，低温致死温度在高山的廷达瑞俄斯蛱蝶（E. tyndarus）中最高，而在栖息于较低海拔、冬季平均温度较高地区的美神蛱蝶中最低。我们通过毛虫冬眠场所积雪的缓冲作用来解释观察到的耐寒性海拔梯度逆转现象，这种缓冲作用在高山地区很强，但在低地则不规则、不可预测且因此不可靠。
