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

研究在柳中岛、冲绳岛、奄美大岛和羽岛进行。在yanahajima，进行了无线电跟踪研究，夜间普查以检查oophis kinkinsis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饮食，并测量了手术温度。在天美大岛，除了上述研究外，还在实验室对蛇的偏好体温进行了测试。在冲绳岛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。由于冲绳弧菌的稀少，只在Uke-jima进行了简短的初步调查。从2006年8月到2007年2月，分别在柳中岛和天美大岛用无线电追踪了8条蛇，每个月记录它们的位置、体温和微栖息地的使用情况。2008年1月和2月，分别在冲绳岛和奄美大岛用12条蛇进行了偏好体温的实验室实验。利用线粒体细胞色素b基因1114序列分析了柳中岛、冲绳岛和奄美大岛6个岛屿的系统发育关系。结果表明：1)冲绳岛和天上大岛的蛇在冬季最活跃，体温为10 ~ 20℃，主要以青蛙为食；2)它们的偏好体温有两个高峰，约25℃和15℃，夜间低于白天；3)柳上岛的蛇在夏季最活跃，体温为25 ~ 30℃，主要以蜥蜴为食。系统发育树表明，冲绳岛和柳中岛两个种群亲缘关系较近，与奄美大岛种群明显分离。总的来说，这些结果表明，与迄今为止报道的其他蛇相比，O. okinavensis具有相对较低的偏好体温，并且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用性，而不是系统亲缘性。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