Predation is one of the most important ecological factors determining the structure and functioning of ecosystems. Among the various strategies used by predators to obtain food, there are those in which they take advantage of the vulnerability of the prey during its foraging bouts. An unexplored example of this strategy is the interaction between vertebrate pollinators and ambush predators. Despite the reports of arboreal tarantulas preying on hummingbirds, little is known about the behaviour of these birds in the presence of their predators. Thus, our study sought to investigate hummingbird behaviour against potential opportunist predators during their search for food resources. We used Heliconia velloziana as a mutualist model, in which, we separated plant flowers in two groups – plants with predators and plants without predators – in order to observe the behaviour of pollinators during their foraging activity. The rate of visitation was also indirectly estimated based on residual nectar and pollen. Our results show that hummingbirds initially avoided contact with the predator, but later they visited both groups indiscriminately. The results suggest that these birds do not have counter‐adaptations to identify invertebrate ambush predators as a threat. Since such predators are generalists and the events of predation are sporadic, they do not exert selective pressures strong enough to lead to the development of evasive behaviours. We conclude that hummingbirds are potential prey for opportunistic ambush predators.

中文翻译：

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猎物的沉默：蜂鸟对花朵上的潜在伏击掠食者没有反应

捕食是决定生态系统结构和功能的最重要的生态因素之一。在捕食者用来获取食物的各种策略中，有一些策略是利用猎物在觅食回合中的脆弱性。这种策略的一个尚未探索的例子是脊椎动物的传粉者与伏击捕食者之间的相互作用。尽管有报道说树栖狼蛛捕食蜂鸟，但对于这些鸟在掠食者面前的行为知之甚少。因此，我们的研究试图调查蜂鸟在寻找食物资源时针对潜在的机会主义掠食者的行为。我们用了Heliconia velloziana作为一种互惠的模型，我们将植物花分成两类-带有捕食者的植物和没有捕食者的植物-以观察授粉媒介在觅食过程中的行为。还基于残留的花蜜和花粉间接估计了探视率。我们的结果表明，蜂鸟最初避免与捕食者接触，但后来他们不分青红皂白地访问了这两个群体。结果表明，这些鸟类没有反适应能力，可以将无脊椎动物伏击掠食者识别为威胁。由于此类掠食者是通才，掠食事件是零星事件，因此它们没有施加足够强大的选择性压力来导致逃避行为的发展。我们得出的结论是，蜂鸟是机会性伏击捕食者的潜在猎物。