Egg rejection is a common and effective defense against avian brood parasitism in which the host either marginalizes or removes the parasitic egg or deserts the parasitized clutch. The ability to recognize and reject a parasitic egg depends on bill morphology, sensory systems, and cognition, all of which are also shaped by other selective processes such as foraging. This begs the question whether specific phenotypes associated with different foraging strategies and diets may constrain or facilitate egg recognition and rejection. Here, we propose a novel hypothesis that host species phenotypes related to foraging ecology and diet may impose morphological and visual sensory constraints on the evolution of egg recognition and rejection. We conducted a comparative analysis of the adult diets and egg rejection rates of 165 current host and non-host species. We found that species have significantly higher egg rejection rates when they (1) consume an omnivorous or animal and fruit dominated diet rather than seeds and grains, (2) forage arboreally rather than aerially or on the ground, or (3) possess relatively larger body sizes. Although correlational in nature, as predicted, these results suggest phenotypes related to specific diets and foraging ecologies may differentially constrain or facilitate evolution of host egg rejection defenses against avian brood parasitism.

中文翻译：

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鸟类饮食和觅食生态制约外来蛋的识别和排斥

卵排斥是针对鸟类寄生寄生的一种常见且有效的防御，其中宿主要么边缘化或移除寄生卵，要么抛弃寄生的离合器。识别和拒绝寄生卵的能力取决于喙形态、感觉系统和认知，所有这些也受其他选择性过程（例如觅食）的影响。这就引出了与不同觅食策略和饮食相关的特定表型是否会限制或促进鸡蛋识别和排斥的问题。在这里，我们提出了一个新假设，即与觅食生态和饮食相关的宿主物种表型可能对卵识别和排斥的进化施加形态和视觉感官限制。我们对 165 种当前宿主和非宿主物种的成虫饮食和卵排斥率进行了比较分析。我们发现，当物种 (1) 以杂食性或动物和水果为主的饮食而不是种子和谷物，(2) 在树上而不是空中或地面上觅食，或 (3) 拥有相对较大的体型。尽管如预测的那样在性质上具有相关性，但这些结果表明与特定饮食和觅食生态相关的表型可能会不同地限制或促进针对鸟类寄生寄生的宿主卵排斥防御的进化。(2) 在树上而不是在空中或地面上觅食，或 (3) 具有相对较大的体型。尽管如预测的那样在性质上具有相关性，但这些结果表明与特定饮食和觅食生态相关的表型可能会不同地限制或促进针对鸟类寄生寄生的宿主卵排斥防御的进化。(2) 在树上而不是在空中或地面上觅食，或 (3) 具有相对较大的体型。尽管如预测的那样在性质上具有相关性，但这些结果表明与特定饮食和觅食生态相关的表型可能会不同地限制或促进针对鸟类寄生寄生的宿主卵排斥防御的进化。