Data from: Mesotocin influences pinyon jay prosociality.

Many species exhibit prosocial behavior, in which one individual’s actions benefit another individual, often without an immediate benefit to itself. The neuropeptide oxytocin is an important hormonal mechanism influencing prosociality in mammals, but it is unclear whether the avian homologue mesotocin plays a similar functional role in birds. Here, we experimentally tested prosociality in pinyon jays (Gymnorhinus cyanocephalus), a highly social corvid species that spontaneously shares food with others. First, we measured prosocial preferences in a prosocial choice task with two different payoff distributions: Prosocial trials delivered food to both the subject and either an empty cage or a partner bird, whereas Altruism trials delivered food only to an empty cage or a partner bird (none to subject). In a second experiment, we examined whether administering mesotocin influenced prosocial preferences. Compared to choices in a control condition, we show that subjects voluntarily delivered food rewards to partners, but only when also receiving food for themselves (Prosocial trials), and administration of high levels of mesotocin increased these behaviors. Thus, in birds, mesotocin seems to play a similar functional role in facilitating prosocial behaviors as oxytocin does in mammals, suggesting an evolutionarily conserved hormonal mechanism for prosociality.诸多物种均存在亲社会行为（prosocial behavior）：即某一个体的行为可使另一个体获益，而自身往往无法获得即时收益。神经肽催产素（oxytocin）是调控哺乳动物亲社会行为的重要激素机制，但目前尚不明确其鸟类同源物——中催产素（mesotocin）——是否在鸟类中发挥类似的功能作用。本研究以矮松鸦（Gymnorhinus cyanocephalus）为实验对象，该物种为高度社会化的鸦科（corvid）鸟类，且会自发与同伴共享食物，针对其亲社会倾向开展了实验检测。首先，我们采用两种不同收益分配范式的亲社会选择任务（prosocial choice task），对矮松鸦的亲社会偏好进行测定：在亲社会试次（prosocial trials）中，食物会同时分配给受试个体与空笼或同伴个体；而在利他试次（Altruism trials）中，食物仅会分配给空笼或同伴个体，受试个体无任何收益。在第二项实验中，我们探究了给予中催产素是否会影响矮松鸦的亲社会偏好。相较于对照组（control condition）的选择结果，我们发现受试个体仅在自身可获得食物的亲社会试次中，会主动为同伴递送食物奖励；且高剂量的中催产素给药可增强这一行为表现。由此可见，在鸟类中，中催产素在促进亲社会行为方面所发挥的功能作用，与哺乳动物体内催产素的功能作用高度相似，这表明亲社会行为的激素调控机制在进化层面具有保守性。