Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia.
Biol Lett. 2013 May 1;9(3):20121144. doi: 10.1098/rsbl.2012.1144. Print 2013 Jun 23.
Odours that accumulate from roosting can attract predators and increase predation risk. Consequently, selection should favour strategies that allow prey to evade detection by predators, including changing roosts. Insectivorous bats that roost in tree hollows regularly switch roosts and roost in different sized groups, strategies that would alter the accumulation of roost odours and are hypothesized to reduce predation risk. We experimentally manipulated the amount and refresh rate of roosting odour cues at 90 artificial bat roosts in Sydney, Australia, to test the hypothesis that odours increase predator visitation. Predators visited roosts with bat faeces significantly more often than untreated control roosts. Roosts with small amounts of faeces mimicking sites used by solitary bats had the greatest rate of visitation. This suggests that bats roosting alone, rather than in groups, have a greater likelihood of disturbance or predation. Roost switching probably decreases the predictability of finding occupied roosts; however, we show that all roosts (those currently or recently occupied) were visited by predators, suggesting generalist urban predators readily investigate potential roosts. This is the first demonstration that bat odours are attractive to predators that use olfactory cues, showing that bats are at risk of predation in visually cryptic roosts.
从栖息处积累的气味会吸引捕食者并增加被捕食的风险。因此，选择应该有利于猎物逃避捕食者的策略，包括改变栖息地。在树洞中栖息的食虫蝙蝠经常更换栖息地，并以不同大小的群体栖息，这些策略会改变栖息地气味的积累，从而降低被捕食的风险。我们在澳大利亚悉尼的 90 个人工蝙蝠栖息地中，对栖息气味线索的数量和更新率进行了实验性操纵，以检验气味会增加捕食者到访的假设。有蝙蝠粪便的栖息地比未处理的对照栖息地更频繁地被捕食者访问。模仿独居蝙蝠使用的栖息地的少量粪便的栖息地访问率最高。这表明单独栖息的蝙蝠，而不是成群栖息的蝙蝠，更有可能受到干扰或被捕食。栖息地的更换可能会降低找到被占用栖息地的可预测性；然而，我们发现所有的栖息地（包括当前或最近被占用的栖息地）都被捕食者访问过，这表明在城市环境中，捕食者很容易调查潜在的栖息地。这是第一个证明蝙蝠气味对使用嗅觉线索的捕食者有吸引力的实验，表明蝙蝠在视觉上隐蔽的栖息地中面临被捕食的风险。
