Data from: Duetting behavior varies with sex, season, and singing role in a tropical oriole (Icterus icterus)

Females and males of many animals combine their vocalizations into coordinated acoustic duets. Duets can mediate both cooperation and conflict between partners, and are common in tropical, sedentary species that may use duets for multiple functions year-round. To elucidate the full range of duet functions, we need to study the individual-level behaviors that generate duets throughout the year. We evaluated multiple functions of duetting behavior in female and male Venezuelan troupials (Icterus icterus) during the breeding and non-breeding seasons, including territory defense, maintaining contact with a mate, and paternity guarding. In both sexes during both seasons, song initiation rates were predicted by conspecific solo and duet rates. However, troupials were more likely to answer their mate to form duets after conspecific duets than after conspecific solos, supporting a territory defense function of duets. Troupials that answered their mate to form duets were also more likely to move toward their mate (than duet initiators and soloists), suggesting that duet participation also functions to maintain contact. During the breeding season, males were particularly likely to fly toward their mate after answering to form a duet. This finding may indicate that males answer to guard paternity, although other predictions of paternity guarding are not supported. Examining individual-level behaviors during both the breeding and non-breeding season revealed multiple functions of troupial duets. Our results are consistent with social selection acting on females and males to maintain contact and territories year-round, and possibly sexual selection on males for functions tied to the breeding season.许多动物的雌性与雄性个体可将各自鸣唱整合为协调一致的声学二重唱（acoustic duets）。二重唱既可介导伴侣间的合作，亦可调节二者间的冲突，在热带定居性物种中尤为常见，这类物种全年可利用二重唱实现多种功能。为阐明二重唱功能的完整范畴，我们需对全年产生二重唱的个体层面行为展开研究。我们于繁殖季与非繁殖季，对委内瑞拉拟鹂（Icterus icterus）雌雄个体的二重唱行为开展了多项功能评估，涵盖领地防御、维持与配偶的联系以及父权保障三个方面。在两个季节的雌雄个体中，鸣唱发起率均可由同种个体的单独鸣唱与二重唱发生频率所预测。不过，相较于同种单独鸣唱情境，委内瑞拉拟鹂在接收到同种二重唱后，更倾向于回应配偶以形成二重唱，这一结果支持了二重唱的领地防御功能。相较于二重唱发起者与单独鸣唱者，参与回应配偶形成二重唱的拟鹂个体，更大概率会向配偶移动，这表明二重唱参与同时也承担着维持配偶间联系的功能。在繁殖季，雄性在回应配偶形成二重唱后，尤其倾向于飞向配偶。这一发现或许提示雄性通过回应行为实现父权保障，尽管父权保障的其他理论预测并未得到本研究支持。对繁殖季与非繁殖季的个体层面行为进行考察后，我们揭示了委内瑞拉拟鹂二重唱的多项功能。我们的研究结果与社会选择对雌雄个体全年维持联系与领地的作用相符，同时也暗示雄性在繁殖季相关功能上可能受到性选择的作用。