作 者 ：林植华,樊晓丽,计翔*
期 刊 ：生态学报 2010年 30卷 9期 页码：2261~2269
关键词：尖吻蝮；舟山眼镜蛇；捕食行为；攻击；体温；感觉器官；
Keywords:Deinagkistrodon acutus, Naja atra, predatory behavior, strike, body temperature, sensory organ,
摘 要 ：毒蛇捕食行为通常可以分为3个阶段：攻击前、攻击和攻击后阶段，其中攻击阶段在整个行为过程中起着决定性的作用。用数码摄像机拍摄了4个体温下尖吻蝮和舟山眼镜蛇幼体捕食小白鼠的行为过程，通过分析10个行为变量来比较两者捕食性攻击模式的差异并检测温度对攻击行为的影响。两种蛇对猎物产生明显不同的攻击反应。攻击前，尖吻蝮感应猎物能力相对较弱，头部移动速度缓慢，准备时间较长；攻击时，尖吻蝮头部移动速度显著大于舟山眼镜蛇；攻击注毒后两种蛇均释放猎物，尖吻蝮头部回缩至攻击前状态的时间间隔相对较短。体温显著影响两种蛇的攻击行为。在检测的温度范围内，两种蛇都在28 ℃体温条件下感应猎物能力达到最好；温度效应对尖吻蝮攻击速度的影响显著，但对舟山眼镜蛇不显著。不同蛇类捕食行为模式以及对体温变化反应的差别可能主要与其利用感觉器官、生境条件上的种间差异有关。
Abstract:The predatory strike behavior of poisonous snakes is generally divided into three successive phases (i.e., prestrike, strike and poststrike phases), with the strike phase being the most crucial to the success of predatory efforts. Cobras of the genus Naja are among the most eye-catching snakes in the world because of their highly venomous nature, and so are pit-vipers of the genus Deinagkistrodon. Having been overhunted by local people for meat, skin, medicine, and handiwork, snakes of these two genera are currently regarded as highly vulnerable in China. In the present study, we used hatchlings of the Chinese cobra Naja atra (N=8) and the five-paced pit-viper Deinagkistrodon acutus (N=18) as the model systems to study whether poisonous snakes that differ in foraging mode, habitat use and body temperature may display different predatory behaviors during encounters with prey. The Chinese cobra is largely an active forager that uses relatively warm habitats in the hilly countryside, whereas the five-paced pit-viper is a typical sit-and-wait forager that uses relatively cool habitats near mountain streams. We examined behavioral responses of these two species to house mice (Mus musculus) by filming the predatory behavior of hatchling snakes at four body temperatures (22、25、28 ℃ and 31 ℃) with a digital camera, and then analyzed 10 behavioral variables to show the possible inter-specific differences and effects of body temperature on strike behavior. Hatchling snakes of these two species hatched and maintained under identical laboratory conditions but displayed quite different strike behaviors during encounters with prey. The mean distance to prey when the alertness reaction (head turning) occurred was shorter in D. acutus than in N. atra. This observation suggests that the ability to detect prey is weaker in D. acutus than in N. atra. During the prestrike phase, hatchling D. acutus moved head to the prey more slowly than did N. atra hatchlings, and the mean preparation time taken to attack the prey was longer in the former species than in the latter one. On the contrary, the head-moving speed was much greater in D. acutus than in N. atra during the strike phase. We found that hatchling snakes of both species released prey soon after the strike behavior and envenomation were complete. Hatchling D. acutus took a shorter time to draw their heads during the poststrike phase in comparison to N. atra hatchlings. Two-way analyses of variance with species and body temperature as the factors on the 10 examined behavioral variables revealed that only distance of strike and duration of strike phase were affected by the species×temperature interaction. Overall, body temperature had an important role in influencing predatory strike behavior. In both species the mean distance of alertness reaction was greater at the body temperature of 28 ℃. The influence of body temperature on strike speed was evident in D. acutus, but not in N. atra. The results of this study may reflect some essential differences in sensory organs between snake species that differ in predatory behavior and habitat use.
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