Turingan Ralph, Sloan Tyler
Department of Biological Sciences, Florida Institute of Technology, 150 West University Boulevard, Melbourne, FL 32901, USA.
Biology (Basel). 2016 Nov 25;5(4):46. doi: 10.3390/biology5040046.
As a consequence of global warming, tropical invasive species are expected to expand their range pole-ward, extending their negative impacts to previously undisturbed, high-latitude ecosystems. Investigating the physiological responses of invasive species to environmental temperature is important because the coupled effects of climate change and species invasion on ecosystems could be more alarming than the effects of each phenomenon independently. Especially in poikilotherms, the rate of motion in muscle-driven biomechanical systems is expected to double for every 10 °C increase in temperature. In this study, we address the question, "How does temperature affect the speed of jaw-movement during prey-capture in invasive fishes?" Kinematic analysis of invasive-fish prey-capture behavior revealed that (1) movement velocities of key components of the feeding mechanism did not double as water temperature increased from 20 °C to 30 °C; and (2) thermal sensitivity (Q10 values) for gape, hyoid, lower-jaw rotation, and cranial rotation velocities at 20 °C and 30 °C ranged from 0.56 to 1.44 in all three species. With the exception of lower-jaw rotation, Q10 values were significantly less than the expected Q10 = 2.0, indicating that feeding kinematics remains consistent despite the change in environmental temperature. It is conceivable that the ability to maintain peak performance at different temperatures helps facilitate the spread of invasive fishes globally.
由于全球变暖，热带入侵物种预计会向极地扩展其分布范围，将其负面影响扩大到以前未受干扰的高纬度生态系统。研究入侵物种对环境温度的生理反应很重要，因为气候变化和物种入侵对生态系统的综合影响可能比这两种现象各自独立产生的影响更令人担忧。特别是对于变温动物，肌肉驱动的生物力学系统中的运动速度预计会随着温度每升高10℃而增加一倍。在本研究中，我们探讨了“温度如何影响入侵鱼类捕食时颌部运动的速度？”对入侵鱼类捕食行为的运动学分析表明：（1）随着水温从20℃升高到30℃，摄食机制关键组成部分的运动速度并未翻倍；（2）在20℃和30℃时，三种鱼类的张口、舌骨、下颌旋转和颅骨旋转速度的热敏感性（Q10值）在0.56至1.44之间。除下颌旋转外，Q10值显著低于预期的Q10 = 2.0，这表明尽管环境温度发生变化，摄食运动学仍保持一致。可以想象，在不同温度下保持最佳性能的能力有助于促进入侵鱼类在全球范围内的扩散。
