Evolution of cold adaptation in subtropical snakes : A study on ecological factors

研究对象为柳叶岛、冲绳岛、奄美大岛、宇惠岛。在Yanaha-jima，无线电跟踪研究，夜间普查，以检查Ovophis okinavensis和猎物的季节性活动模式，标记-再捕获研究，以检查蛇的运动模式和饮食，并测量手术温度。在奄美大岛，除了上述研究外，还在实验室中测试了蛇的首选体温。在已进行长期现场研究的冲绳岛，仅检查了手术温度和首选体温。由于O.在冲绳县的调查中，对宇惠岛进行了初步的调查。从2006年8月和2007年2月起，分别在Yanaha-jima和Amami-ohshima对8条蛇进行无线电跟踪，每月记录它们的位置、体温和微栖息地的使用情况。第二部分为实验室首选体温的实验研究。 关于我们 分别于2008年1月和2月在冲绳岛和奄美大岛使用12条蛇进行了试验。利用线粒体细胞色素B基因的1114 bp序列，对柳叶岛、冲绳岛和奄美大岛等6个岛屿的系统发育关系进行了研究。结果表明：（1）冲绳岛和奄美大岛的蛇类冬季活动最频繁，体温在10-20℃之间，主要以蛙类为食;（3）柳叶岛蛇类夏季活动最多，体温25-30℃，专食蜥蜴。系统发育树显示冲绳岛和柳叶岛两个种群的亲缘关系较近，与奄美大岛种群明显分离。总体而言，这些结果表明，O。与迄今报道的其他蛇类相比，冲绳蛇具有相对较低的偏好体温，季节性活动模式可能在很大程度上取决于当地食物资源的可获得性，而不是系统发育的亲和力。少

Research was conducted on Yanaha-jima, Okinawa-jima, Amami-ohshima, and Uke-jima Islands. On Yanaha-jima, radio-tracking study, nighttime census to examine seasonal activity patterns of Ovophis okinavensis and prey animals, mark-recapture study to examine movement patterns and diet of the snake, and measurements of operative temperature were conducted. On Amami-ohshima, in addition to the above studies, preferred body temperature of the snake was tested in the laboratory. On Okinawa-jima, where long-term field study had been conducted, only the examination of operative temperature and preferred body temperature were made. Because of the scarcity of O. okinavensis, only a brief preliminary survey was conducted on Uke-jima. Eight snakes each were radio-tracked from August 2006 and February 2007 on Yanaha-jima and Amami-ohshima, respectively, and their location, body temperature, and microhabitat use were recorded every month. Laboratory experiments on preferred body temperature were cond … More ucted using 12 snakes each in January and February 2008 on Okinawa-jima and Amami-ohshima, respectively. Phylogenetic relationships among six islands including Yanaha-jima, Okinawa-jima, and Amami-ohshima were investigated using 1114 by of the Mitochondrial cytochrome b gene. The results showed that 1) snakes on Okinawa-jima and Amami-ohshima are most active in winter with a body temperature of 10-20℃ and predominantly feed on frogs, 2) their preferred body temperature exhibits two peaks, ca. 25℃ and 15℃, and is lower at night than in the daytime, and 3) snakes on Yanaha-jima are most active in summer with a body temperature of 25-30℃ and exclusively feed on lizards. Obtained phylogenetic tree indicated a close affinity of the Okinawa-jima and Yanaha-jima populations, which are clearly separated from the Amami-ohshima population. Overall, these results suggest that O. okinavensis has relatively low preferred body temperature compared to other snakes hitherto reported and that seasonal activity patterns may largely depend on local availability of food resources rather than phylogenetic affinity. Less