Macedo_etal_AnimBehav

Behavioural data and R code to reproduce analyses of the paper "Differences in plumage coloration predict female but not male territorial responses in three antbird sister species pairs" published in Animal Behaviour by Gabriel Macedo, Gustavo A. Bravo, Rafael Sobral Marcondes , Elizabeth P. Derryberry , and Cibele Biondo.

Introduction:
In this study, we hypothesized that the eumelanin concentration in the plumage of antbirds (a family of Neotropical birds) function as ornaments that evolve under social selection, signaling quality or competitive ability of females and males. We tested the prediction that conspicuous eumelanic dark plumage patches are positively associated with territorial responses of females and males of three antbird sister species pairs:
Drymophila ochropyga and D. genei;
Myrmoderus loricatus and M. squamosus;
Thamnophilus torquatus and T. ruficapillus.
We compared responses of between sexes and sister species.
Females of Drymophila ochropyga bear more conspicuous dark plumage patches than females of D. genei. Males of these species are similarly coloured.
Females of Myrmoderus loricatus bear more conspicuous dark plumage patches than females of M. squamosus. Males of these species are similarly coloured.
Males of Thamnophilus torquatus bear more conspicuous dark plumage patches than males of T. ruficapillus. Females of these species are similarly coloured.

Methods:
Using playback experiments in the field, we assessed the strength of territorial responses by measuring number of songs, latency to approach and interaction time of females and males that were forming social pairs. Strong territorial responses correspond to higher values of these variables. We simulated territorial intrusions by a solitary female (female solo song), a solitary male (male solo song), and a social pair (duetting social pair).

Results:
We found that females of Drymophila ochropyga and Mymoderus loricatus – which bear more conspicuous dark plumage patches – showed stronger territorial responses than females of D. genei and M. squamosus, respectively. Stronger responses occurred against simulated female and/or male intruders, but not against simulated social pairs. Males of Drymophila and Mymorderus species – which are similarly colored – showed similar territorial responses. However, contrary to out predictions, males of Thamnophilus torquatus – which bear more conspicuous dark plumage patches – did not show stronger territorial responses than males of T. ruficapillus. Females of the Thamnophilus species – which are similarly colored – showed weak, similar territorial responses.

Discussion:
Our results suggest that eumelanic patches in antbirds may function as ornaments in intra- and intersexual contexts in females. In contrast, in species pairs with greater interspecific differences in male ornamentation, territorial competition may occur predominantly among males and female mate choice may drive the evolution of male ornamentation.

本研究旨在探讨蚁鸟（新热带鸟类家族）羽毛中的黑素浓度是否作为装饰性特征，在社会选择的作用下进化，以指示雌雄两性的品质或竞争能力。研究者通过比较三种蚁鸟姐妹种对（Drymophila ochropyga 与 D. genei；Myrmoderus loricatus 与 M. squamosus；Thamnophilus torquatus 与 T. ruficapillus）的雌雄个体在显眼的黑素羽毛斑块的明显程度与领土反应之间的关系，对该假设进行了验证。研究发现，携带更为显眼黑素羽毛斑块的 Drymophila ochropyga 和 Myrmoderus loricatus 的雌鸟，其领土反应强度高于 D. genei 和 M. squamosus 的雌鸟。在模拟雌性和/或雄性入侵者的情况下，领土反应更为强烈，但面对模拟的社会对，反应则不明显。Drymophila 和 Myrmoderus 种类的雄鸟，由于羽毛颜色相似，其领土反应也相似。然而，与预期相反，携带更为显眼黑素羽毛斑块的 Thamnophilus torquatus 的雄鸟，其领土反应强度并未显著高于 T. ruficapillus 的雄鸟。Thamnophilus 种类的雌鸟，由于羽毛颜色相似，表现出较弱且相似的领土反应。