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

研究是在柳叶岛、冲绳岛、大岛和宇岛上进行的。在YANAHA-JIMA，进行了无线电跟踪研究，夜间普查以检查卵子和猎物的季节性活动模式，标记-重新捕获研究以检查蛇的运动模式和食性，并测量了工作温度。在Amami-Ohshima上，除了上述研究外，还在实验室测试了蛇的喜好体温。在冲绳-吉马，进行了长期的实地研究，只进行了手术温度和首选体温的检查。由于okinvensis的稀有，只对乌克吉马进行了简短的初步调查。从2006年8月和2007年2月分别在柳叶岛和大岛县对8条蛇进行了无线电跟踪，并每月记录它们的位置、体温和微生境使用情况。…推荐体温的实验室实验更多的是在2008年1月和2月分别在冲绳-吉马和滨海-大岛各使用了12条蛇。利用线粒体细胞色素b基因1114序列分析了柳叶岛、冲绳岛和大岛岛等6个岛屿的系统发育关系。结果表明：1)冲绳-吉马和大岛蛇在冬季最活跃，体温为10-20℃，以青蛙为主；2)它们的喜好体温出现两个峰值，约25℃和15℃，夜间低于白天；3)柳叶岛蛇夏季最活跃，体温25-30℃，以蜥蜴为主。获得的系统发育树表明冲绳-JIMA和柳叶-JIMA种群的亲缘关系很近，这两个种群明显地与Amami-Ohshima种群分开。总体而言，这些结果表明，与迄今报道的其他蛇相比，Okinvensis的首选体温相对较低，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，而不是系统发育亲缘关系。较少

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