Graduate School of Environmental and Life Science, Okayama University, Okayama 700-8530, Japan.
Biol Lett. 2023 Mar;19(3):20230028. doi: 10.1098/rsbl.2023.0028. Epub 2023 Mar 29.
Death-feigning behaviour is a phenomenon in which a prey is rendered motionless due to stimulation or threat from a predator. This anti-predator defence mechanism has been observed across numerous animal taxa and is considered adaptive in nature. However, longer durations of death feigning can result in decreased opportunities for feeding and reproduction, and therefore is often associated with fitness costs as compared to environments without predators. Differences have also been observed in the frequencies and durations of death feigning within populations, and these differences are thought to be influenced by the balance between survival and other fitness costs. Furthermore, this balance is predicted to vary in response to changes in environmental conditions. In this study, we examined the death feigning in 38 populations of the red flour beetle (). Our results demonstrate that frequencies and durations of the death feigning in show geographical variations and a latitude cline, indicating that this behaviour is influenced by location as well as latitude. This study is the first to demonstrate the existence of a latitudinal cline in death feigning and suggests that death-feigning behaviour might have evolved in response to environmental factors that vary with latitude.
装死行为是一种现象，即猎物由于受到捕食者的刺激或威胁而变得一动不动。这种抗捕食防御机制在许多动物分类群中都有观察到，被认为是自然适应的。然而，较长时间的装死会导致觅食和繁殖机会减少，因此与没有捕食者的环境相比，通常与适应度成本相关。在种群内也观察到装死的频率和持续时间存在差异，人们认为这些差异受到生存和其他适应度成本之间平衡的影响。此外，预计这种平衡会随着环境条件的变化而变化。在这项研究中，我们检查了 38 个种群的装死行为。我们的研究结果表明，（拟步甲科昆虫）的装死频率和持续时间存在地理差异和纬度梯度，表明这种行为受到位置和纬度的影响。这项研究首次证明了装死行为存在纬度梯度，并表明装死行为可能是为了应对随纬度变化的环境因素而进化的。
