Animals learn to associate sensory cues with the palatability of food in order to avoid bitterness in food (a common sign of toxicity). Associations are important for active foraging predators to avoid unpalatable prey and to invest energy in searching for palatable prey only. However, it has been suggested that sit-and-wait predators might rely on the opportunity that palatable prey approach them by chance: the most efficient strategy could be to catch every available prey and then decide whether to ingest them or not. In the present study, we investigated avoidance learning in a sit-and-wait predator, the praying mantis (Tenodera aridifolia). To examine the effects of conspicuousness and novelty of prey on avoidance learning, we used three different prey species: mealworms (novel prey), honeybees (novel prey with conspicuous signals) and crickets (familiar prey). We sequentially presented the prey species in pairs and made one of them artificially bitter. In the absence of bitterness, the mantises consumed bees and crickets more frequently than mealworms. When the prey were made bitter, the mantises still continued to attack bitter crickets as expected. However, they reduced their attacks on bitter mealworms more than on bitter bees. This contrasts with the fact that conspicuous signals (e.g. coloration in bees) facilitate avoidance learning in active foraging predators. Surprisingly, we found that the bitter bees were totally rejected after an attack whereas bitter mealworms were partially eaten (~35%). Our results highlight the fact that the mantises might maintain a selection pressure on bees, and perhaps on aposematic species in general.

中文翻译：

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螳螂 (Tenodera aridifolia) 的厌恶学习，一种坐等捕食者

动物学会将感官线索与食物的适口性联系起来，以避免食物中的苦味（一种常见的毒性迹象）。协会对于积极觅食的捕食者避免不好吃的猎物和投入精力只寻找可口的猎物很重要。然而，有人建议坐等捕食者可能依赖于可口的猎物偶然接近它们的机会：最有效的策略可能是捕捉每一个可用的猎物，然后决定是否摄取它们。在本研究中，我们调查了一种坐等捕食者螳螂 (Tenodera aridifolia) 的回避学习。为了检查猎物的显眼性和新颖性对回避学习的影响，我们使用了三种不同的猎物物种：粉虫（新猎物）、蜜蜂（具有明显信号的新猎物）和蟋蟀（熟悉的猎物）。我们依次成对展示了猎物，并人为地使其中一个变苦。在没有苦味的情况下，螳螂比粉虫更频繁地吃蜜蜂和蟋蟀。当猎物变得苦涩时，螳螂仍然像预期的那样继续攻击苦蟋蟀。然而，与对苦蜂相比，它们对苦粉虫的攻击减少了更多。这与显着信号（例如蜜蜂的颜色）促进主动觅食捕食者的回避学习这一事实形成对比。令人惊讶的是，我们发现苦蜂在攻击后完全被拒绝，而苦粉虫被部分吃掉（~35%）。我们的结果强调了这样一个事实，即螳螂可能会对蜜蜂保持选择压力，