Département des Sciences Biologiques, Université du Québec à Montréal, Montréal, Qc, Canada.
University of Hong Kong, School of Biological Sciences, Hong Kong SAR, China.
PLoS One. 2018 Oct 10;13(10):e0204019. doi: 10.1371/journal.pone.0204019. eCollection 2018.
In furtive predation, a predator is able to exploit its prey without generating significant defensive behaviors from them. However, in aphidophagous guild, if furtive predator can benefit from dilution effects generated by the aphids, they also suffer from intraguild predation from more mobile and active-searching predators. In this context ant-tended aphid colonies might not only represent an important food source but also potentially an enemy-free space for furtive predators if they remain unharmed by ants while other active predators are being repelled. Here we use the furtive predator Aphidoletes aphidimyza and two distinct instars of an active-searching predator, the Asian ladybeetle Harmonia axyridis, to test hypotheses related to predator persistence within aphid colonies in presence of ants. Our results show that persistence rate over time of the furtive predator was not affected by ant presence while it was strongly reduced for both instars of the active-searching predator. Furthermore, when ran in paired trials within ant-tended aphid colonies, furtive predator persistence rate was significantly higher than for active-searching predators, with these latter always leaving the plants quicker. Finally, we tested the importance of predator mobility in detection susceptibility and aggressive responses in ants using mobile and immobile active-searching predators. While the number of antennal palpations was similar for both treatments indicating similar detection rate, the number of ant attacks was significantly higher on mobile individuals highlighting the importance of movement in triggering aggressive responses in ants. Overall our results indicate that furtive predation represents an efficient strategy to limit ant aggressions, while the exclusion of active-searching predators might create an enemy-free space for furtive predators within ant-tended aphid colonies.
在隐匿捕食中，捕食者能够在不引起猎物明显防御行为的情况下捕食猎物。然而，在食蚜蝇中，如果隐匿捕食者能够受益于蚜虫产生的稀释效应，它们也会受到更具流动性和积极搜索的捕食者的种内捕食。在这种情况下，蚂蚁保护的蚜虫群体不仅可能成为隐匿捕食者的重要食物来源，而且如果它们在不被蚂蚁伤害的情况下，其他活跃的捕食者被驱赶，它们也可能成为隐匿捕食者的无敌人空间。在这里，我们使用隐匿捕食者蚜小蜂 Aphidoletes aphidimyza 和两种不同龄期的活跃搜索捕食者亚洲瓢虫 Harmonia axyridis 来测试与蚂蚁存在时捕食者在蚜虫群体中持续存在相关的假设。我们的结果表明，隐匿捕食者的持续时间随着时间的推移而不受蚂蚁存在的影响，而活跃搜索捕食者的两个龄期的持续时间则大大减少。此外，当在蚂蚁保护的蚜虫群体内进行配对试验时，隐匿捕食者的持续时间明显高于活跃搜索捕食者，后者总是更快地离开植物。最后，我们使用移动和不移动的活跃搜索捕食者来测试捕食者的移动能力在蚂蚁的检测易感性和攻击反应中的重要性。虽然两种处理的触角拍打次数相似，表明检测率相似，但移动个体的蚂蚁攻击次数明显更高，突出了运动在触发蚂蚁攻击反应中的重要性。总体而言，我们的结果表明，隐匿捕食是一种限制蚂蚁攻击的有效策略，而排除活跃搜索的捕食者可能会在蚂蚁保护的蚜虫群体中为隐匿捕食者创造一个无敌人空间。
