The effects of temperature on the defensive strikes of rattlesnakes
The effects of temperature on the defensive strikes of rattlesnakes
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DOI：
10.1242/jeb.223859
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发表时间：
2020-01
影响因子：
2.8
通讯作者：
M. Whitford;G. Freymiller;T. Higham;R. Clark
中科院分区：
文献类型：
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作者：
M. Whitford;G. Freymiller;T. Higham;R. Clark
摘要由于温度对肌肉生理的影响，外温动物的运动受到体温的限制。由于物理性能往往会影响捕食者-猎物相互作用的结果，环境温度可以影响外温动物捕获猎物和/或保护自己免受捕食者的能力。然而，先前对外温动物运动学的研究表明，某些物种在攻击或防御时可能会使用弹性存储机制，从而减轻次优温度的影响。响尾蛇（响尾蛇属）是一种奇特的变温毒蛇类蛇，它们依靠神秘、嘎嘎作响和攻击来阻止捕食者。我们研究了体温对两种响尾蛇（Crotalus oreganus helleri和Crotalus scutulatus）的行为和运动学的影响，当防御性地攻击威胁性刺激时。我们记录了体温在15-35°C范围内的防御性攻击。我们发现，攻击速度和攻击过程中张口的速度与温度呈正相关。我们还发现了一个边际效应的温度对罢工的概率，罢工的潜伏期和罢工的结果。总的来说，温暖的蛇更容易攻击，攻击更快，张开嘴更快，比寒冷的蛇更早达到最大的张开。然而，温度的影响小于纯肌肉驱动运动的预期。我们的研究结果表明，虽然响尾蛇在更冷的体温捕食的风险更大，他们的罢工性能下降可能会在一定程度上减轻采用除了骨骼肌收缩（例如弹性储能）的权力罢工的机制。突出显示的文章：毒蛇罢工运动学在一系列生态相关的温度表明，毒蛇的防御罢工受温度的影响，但低于预期，如果运动是纯粹的肌肉驱动。
ABSTRACT Movements of ectotherms are constrained by their body temperature owing to the effects of temperature on muscle physiology. As physical performance often affects the outcome of predator–prey interactions, environmental temperature can influence the ability of ectotherms to capture prey and/or defend themselves against predators. However, previous research on the kinematics of ectotherms suggests that some species may use elastic storage mechanisms when attacking or defending, thereby mitigating the effects of sub-optimal temperature. Rattlesnakes (Crotalus spp.) are a speciose group of ectothermic viperid snakes that rely on crypsis, rattling and striking to deter predators. We examined the influence of body temperature on the behavior and kinematics of two rattlesnake species (Crotalus oreganus helleri and Crotalus scutulatus) when defensively striking towards a threatening stimulus. We recorded defensive strikes at body temperatures ranging from 15–35°C. We found that strike speed and speed of mouth gaping during the strike were positively correlated with temperature. We also found a marginal effect of temperature on the probability of striking, latency to strike and strike outcome. Overall, warmer snakes are more likely to strike, strike faster, open their mouth faster and reach maximum gape earlier than colder snakes. However, the effects of temperature were less than would be expected for purely muscle-driven movements. Our results suggest that, although rattlesnakes are at a greater risk of predation at colder body temperatures, their decrease in strike performance may be mitigated to some extent by employing mechanisms in addition to skeletal muscle contraction (e.g. elastic energy storage) to power strikes. Highlighted Article: Viper strike kinematics across a range of ecologically relevant temperatures show that defensive strikes of vipers are affected by temperature, but less than would be expected if the movement was purely muscle-driven.