Eavesdropping on Referential Yellow Warbler Alarm Calls by Red-Winged Blackbirds Is Mediated by Brood Parasitism Risk
Eavesdropping on Referential Yellow Warbler Alarm Calls by Red-Winged Blackbirds Is Mediated by Brood Parasitism Risk
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DOI：
10.3389/fevo.2021.706170
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发表时间：
2021-10-05
影响因子：
3
通讯作者：
Hauber, Mark E.
中科院分区：
文献类型：
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作者：
Lawson, Shelby L.;Enos, Janice K.;Hauber, Mark E.
指示特定类型危险的参照警报呼叫在不同的脊椎动物谱系中很常见。不同的警报呼叫可以指示各种威胁，这些威胁通常需要特定的操作才能规避。因此，为了从呼叫中受益，参考警报呼叫的监听者必须能够解码发出信号的威胁并以适当的方式对其作出响应。黄莺(Setophaga Petechia)发出指代的“seet”叫声，发出信号，表明附近存在专性繁殖的寄生褐头牛鸟(Molothrus Ater)，它们在包括黄莺在内的其他物种的巢中产卵。我们之前的回放实验发现，同样被褐头牛鸟寄生的红翼黑鸟(Agelaius Phoeniceus)在繁殖的孵化阶段窃听黄莺的叫声并对其做出强烈反应，其攻击性类似于对牛鸟的叫声和捕食者的叫声的反应。为了评估红翼黑鸟对SEET叫声的反应是否随着它们自身寄生幼鸟的风险而变化，我们在繁殖的雏鸟阶段(当幼鸟寄生的风险低于孵化阶段)进行了相同的回放。正如预测的那样，我们发现，在雏鸟阶段，黑鸟对牛鸟的鸣叫和林莺的反寄生参照警报呼叫的攻击与当前幼鸟寄生的低风险是平行的。这些结果进一步支持了红翼黑鸟灵活地响应黄莺的反寄生参照呼叫，作为抵御自家巢内幼鸟寄生的一线防御。
Referential alarm calls that denote specific types of dangers are common across diverse vertebrate lineages. Different alarm calls can indicate a variety of threats, which often require specific actions to evade. Thus, to benefit from the call, listeners of referential alarm calls must be able to decode the signaled threat and respond to it in an appropriate manner. Yellow warblers (Setophaga petechia) produce referential "seet" calls that signal to conspecifics the presence of nearby obligate brood parasitic brown-headed cowbirds (Molothrus ater), which lay their eggs in the nests of other species, including yellow warblers. Our previous playback experiments have found that red-winged blackbirds (Agelaius phoeniceus), a species also parasitized by brown-headed cowbirds, eavesdrop upon and respond strongly to yellow warbler seet calls during the incubation stage of breeding with aggression similar to responses to both cowbird chatters and predator calls. To assess whether red-winged blackbird responses to seet calls vary with their own risk of brood parasitism, we presented the same playbacks during the nestling stage of breeding (when the risk of brood parasitism is lower than during incubation). As predicted, we found that blackbirds mediated their aggression toward both cowbird chatter calls and the warblers' anti-parasitic referential alarm calls in parallel with the low current risk of brood parasitism during the nestling stage. These results further support that red-winged blackbirds flexibly respond to yellow warbler antiparasitic referential calls as a frontline defense against brood parasitism at their own nests.