Abstract

Birds’ behavioral response to brood parasitism can be influenced not only by evolution but also by context and individual experience. This could include nest sanitation, in which birds remove debris from their nests. Ultimately, nest sanitation behavior might be an evolutionary precursor to the rejection of parasitic eggs. Proximately, the context or experience of performing nest sanitation behavior might increase the detection or prime the removal of parasitic eggs, but evidence to date is limited. We tested incubation-stage nests of herring gulls Larus argentatus to ask whether nest sanitation increased parasitic egg rejection. In an initial set of 160 single-object experiments, small, red, blocky objects were usually rejected (18 of 20 nests), whereas life-sized, 3D-printed herring gull eggs were not rejected whether red (0 of 20) or the olive-tan base color of herring gull eggs (0 of 20). Next, we simultaneously presented a red, 3D-printed gull egg and a small, red block. These nests exhibited frequent nest sanitation (small, red block removed at 40 of 48 nests), but egg rejection remained uncommon (5 of those 40) and not significantly different from control nests (5 of 49) which received the parasitic egg but not the priming object. Thus, performance of nest sanitation did not shape individuals’ responses to parasitism. Interestingly, parents were more likely to reject the parasitic egg when they were present as we approached the nest to add the experimental objects. Depending on the underlying mechanism, this could also be a case of experience creating variation in responses to parasitism.

中文翻译：

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巢穴卫生行为不会增加鲱鸥寄生卵排斥的可能性

摘要

鸟类对育雏寄生的行为反应不仅会受到进化的影响，还会受到环境和个人经验的影响。这可能包括巢穴卫生，其中鸟类从巢穴中清除碎片。最终，巢穴卫生行为可能是排斥寄生卵的进化前兆。近似地，执行巢穴卫生行为的背景或经验可能会增加寄生卵的检测或清除，但迄今为止的证据有限。我们测试了鲱鱼鸥（ Larus argentatus）的孵化阶段巢穴询问巢穴卫生是否增加了对寄生卵的排斥。在最初的 160 个单物体实验中，小的、红色的块状物体通常被拒绝（20 个巢中的 18 个），而真人大小的 3D 打印鲱鸥蛋无论是红色（20 个中的 0 个）还是鲱鱼海鸥蛋的橄榄褐色底色（0 个，共 20 个）。接下来，我们同时展示了一个红色的 3D 打印海鸥蛋和一个小的红色块。这些巢穴表现出频繁的巢穴卫生（48 个巢穴中的 40 个去除了小红块），但排卵仍然不常见（这 40 个巢穴中的 5 个），并且与接受寄生卵​​但没有接受寄生卵​​的对照巢穴（49 个巢穴中的 5 个）没有显着差异启动对象。因此，巢穴卫生的表现并没有影响个体对寄生的反应。有趣的是，当我们接近巢穴添加实验对象时，父母更有可能拒绝寄生卵。根据潜在的机制，这也可能是一个经验案例，导致对寄生的反应产生变化。