Pairing status moderates both the production of and responses to anti-parasitic referential alarm calls in male yellow warblers
Pairing status moderates both the production of and responses to anti-parasitic referential alarm calls in male yellow warblers
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DOI：
10.1111/eth.13139
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发表时间：
2021-02-22
期刊：
影响因子：
1.7
通讯作者：
Hauber, Mark E.
中科院分区：
文献类型：
--
作者：
Lawson, Shelby L.;Enos, Janice K.;Hauber, Mark E.
保护后代会产生时间和精力上的成本，对父母来说可能是危险的。因此，这种代价高昂的行为的强度应该反映出对生殖产出的感知风险。当面对褐头牛鸟(Molothrus Ater)代价高昂的幼鸟寄生时，牛鸟在异种巢中产卵，并使宿主照顾它们的幼鸟时，黄莺(Setophaga Petecia)会使用指代的“seet”叫声来警告它们的配偶寄生的危险。黄莺无论雌雄，只有在鸣叫或鸣叫时才会发出这种叫声。SEET叫声主要在繁殖的产卵和孵化阶段产生，此时幼鸟寄生的风险最高，而不是在雏鸟阶段。另一方面，一般警报呼叫(芯片)在整个筑巢周期中产生，也用于与筑巢无关的同种交互。我们假设，在繁殖之前，环境也会影响反应，因此没有交配和活跃巢的黄莺不太可能对模拟幼鸟寄生风险的回放做出反应。为了验证这一假设，我们播放了两种筑巢威胁--牛鸟(寄生虫)和蓝鸟(海燕；巢捕食者)--在未交配的雄莺(未配对)和有已知配偶的雄莺(配对)的领地上。我们发现，未配对的雄性对表明巢威胁的回放没有反应，而与对照回放相比，配对的雄性对这些回放明显更具攻击性和发言权。然而，配对和未配对的雄性对芯片的叫声都有声音反应，这对雄性来说是信息，无论配对状态如何。在繁殖的最早阶段，雄性黄莺似乎会根据特定威胁刺激的上下文相关性来调整它们的反应，我们的工作结合先前的研究进一步支持了参照叫声与幼鸟寄生的阶段特定风险有关。
Defending offspring incurs temporal and energetic costs and can be dangerous for the parents. Accordingly, the intensity of this costly behavior should reflect the perceived risk to the reproductive output. When facing costly brood parasitism by brown-headed cowbirds (Molothrus ater), where cowbirds lay eggs in heterospecific nests and cause the hosts to care for their young, yellow warblers (Setophaga petechia) use referential "seet" calls to warn their mates of the parasitic danger. Yellow warblers of both sexes produce this call only in response to cowbirds or seet-calling conspecifics. Seet calls are mainly produced during the laying and incubation stages of breeding, when risk of brood parasitism is highest, rather than during the nestling stage. On the other hand, general alarm calls (chips) are produced throughout the nesting cycle and are also used in conspecific interactions unrelated to nesting. We hypothesized that context shapes responses prior to breeding as well, such that yellow warblers without a mate and active nest would be less likely to respond to playbacks that simulate brood parasitism risk. To test this hypothesis, we presented playbacks of two nest threats, cowbirds (brood parasite) and blue jays (Cyanocitta cristata; nest predator), on territories of unmated male warblers (unpaired) and male warblers with a known mate (paired). We found that unpaired males were unresponsive toward playbacks indicating nest threats, whereas paired males were significantly more aggressive and vocal toward these playbacks compared to control playbacks. However, both paired and unpaired males were vocally responsive toward chip calls, which are informative for males regardless of pairing status. Male yellow warblers appear to adjust their responses during the earliest stages of breeding depending on the contextual relevance of specific threat stimuli, and together with prior studies, our work further supports that referential seet calls are associated with stage-specific risk of brood parasitism.