Montana Cooperative Wildlife Research Unit, Wildlife Biology Program, University of Montana, Missoula, MT, USA.
Montana Cooperative Wildlife Research Unit, Division of Biological Sciences, University of Montana, Missoula, MT, USA.
Ecol Lett. 2020 Apr;23(4):642-652. doi: 10.1111/ele.13464. Epub 2020 Jan 28.
Survival rates vary dramatically among species and predictably across latitudes, but causes of this variation are unclear. The rate-of-living hypothesis posits that physiological damage from metabolism causes species with faster metabolic rates to exhibit lower survival rates. However, whether increased survival commonly observed in tropical and south temperate latitudes is associated with slower metabolic rate remains unclear. We compared metabolic rates and annual survival rates that we measured across 46 species, and from literature data across 147 species of birds in northern, southern and tropical latitudes. High metabolic rates were associated with lower survival but survival varied substantially among latitudinal regions independent of metabolism. The inability of metabolic rate to explain latitudinal variation in survival suggests (1) species may evolve physiological mechanisms that mitigate physiological damage from cellular metabolism and (2) extrinsic rather than intrinsic sources of mortality are the primary causes of latitudinal differences in survival.
存活率在不同物种之间差异显著，而且在纬度上也可以预测，但这种差异的原因尚不清楚。生活率假说认为，新陈代谢造成的生理损伤会导致代谢率较高的物种表现出较低的存活率。然而，热带和南温带中常见的存活率增加是否与较低的代谢率有关尚不清楚。我们比较了在北纬、南纬和热带纬度范围内测量的 46 种鸟类的代谢率和年存活率，以及从文献数据中获得的 147 种鸟类的代谢率和年存活率。高代谢率与低存活率相关，但存活率在纬度区域之间存在很大差异，而代谢率则不受影响。代谢率无法解释存活率的纬度变化表明：（1）物种可能进化出了减轻细胞代谢造成的生理损伤的生理机制；（2）外在而非内在的死亡原因是造成存活率纬度差异的主要原因。
