Nest substrate and tool shape significantly affect the mechanics and energy requirements of avian eggshell puncture
Nest substrate and tool shape significantly affect the mechanics and energy requirements of avian eggshell puncture
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DOI：
10.1242/jeb.238832
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发表时间：
2021-04-01
影响因子：
2.8
通讯作者：
Anderson, Philip S. L.
中科院分区：
文献类型：
--
作者：
Clark, Daniel L.;Hauber, Mark E.;Anderson, Philip S. L.
一些鸟类专性育雏寄生虫的宿主物种拒绝寄生卵从他们的巢，而其他人接受他们，即使他们承认他们是外来的。解释这种看似适应不良行为的一个假设是，受体无法刺穿并去除寄生蛋壳。以前的研究报告的力量和能量所需的打破育雏寄生虫的蛋壳通常是静态测试对硬基板表面进行。在这里，我们认为主机巢作为基板，以模拟这个潜在的关键方面的自然环境蛋穿刺，同时测试所需的能量，打破鸟类蛋壳。具体而言，作为概念的证明，我们在一系列条件下刺破了国内鸡蛋：不同的工具形状（锋利与钝），工具动态（静态与动态）和天然鸟巢（三种宿主物种）的存在。结果表明，一组复杂的统计学显着的工具形状，穿刺动力学和巢基板之间的相互作用。具体而言，打破鸡蛋所需的能量是更大的静态测试比动态测试，但只有当使用巢基板和钝工具。反过来，在静态测试中，除了一个巢显着增加了两种工具类型的能量需求，而在动态测试中，与巢的存在相关的能量的增加是显着的，只有当使用锋利的工具。在越来越自然的背景下描述蛋壳穿刺的过程将有助于理解育雏寄生虫的宿主是否以及如何进化以拒绝外来卵。
Some host species of avian obligate brood parasites reject parasitic eggs from their nest whereas others accept them, even though they recognize them as foreign. One hypothesis to explain this seemingly maladaptive behavior is that acceptors are unable to pierce and remove the parasitic eggshell. Previous studies reporting on the force and energy required to break brood parasites' eggshells were typically static tests performed against hard substrate surfaces. Here, we considered host nest as a substrate to simulate this potentially critical aspect of the natural context for egg puncture while testing the energy required to break avian eggshells. Specifically, as a proof of concept, we punctured domestic chicken eggs under a series of conditions: varying tool shape (sharp versus blunt), tool dynamics (static versus dynamic) and the presence of natural bird nests (of three host species). The results show a complex set of statistically significant interactions between tool shapes, puncture dynamics and nest substrates. Specifically, the energy required to break eggs was greater for the static tests than for the dynamic tests, but only when using a nest substrate and a blunt tool. In turn, in the static tests, the addition of a nest significantly increased energy requirements for both tool types, whereas during dynamic tests, the increase in energy associated with the nest presence was significant only when using the sharp tool. Characterizing the process of eggshell puncture in increasingly naturalistic contexts will help in understanding whether and how hosts of brood parasites evolve to reject foreign eggs.