Department of Vertebrate Zoology and Anthropology, Institute for Research on Biodiversity, University of Szczecin, Wąska 13, PL-71-415, Szczecin, Poland.
Institute of Zoology, Poznan University of Life Sciences, Wojska Polskiego 71C, PL 60-625, Poznań, Poland.
Sci Rep. 2018 Jan 26;8(1):1654. doi: 10.1038/s41598-018-20128-3.
Same-sex sexual behaviour has been noted among social animals. However, because of the large number of observations necessary, data from controlled experiments are lacking. In this study, we performed experiments to evaluate the effects of male and female removal in colonies of the feral pigeon (Columba livia f. urbana). After the experimental removal of males, five long-lasting female-female pairs occurred. We found that those pairs could successfully raise offspring in a manner comparable to female-male pairs. Same-sex sexual behaviour and pairing in females is thus a better alternative to postponed breeding or breeding alone without the help of a partner. In contrast, in the case of female-removal experiments, same-sex pairing behaviour occurred in males as a temporary phenomenon with characteristic mutual aggression. Additionally, under a male-biased sex ratio, we observed father-son and father-daughter copulations. To the best of our knowledge, these results are the first obtained under controlled experimental conditions which demonstrate that the sex ratio of a population can shift the social structure and cause cooperative same-sex breeding behaviour to arise in a monogamous species.
同性性行为已在社会性动物中被观察到。然而，由于需要进行大量的观察，因此缺乏来自控制实验的数据。在这项研究中，我们对野鸽（Columba livia f. urbana）的群体进行了实验，以评估雄性和雌性移除的效果。在雄性被实验性移除后，发生了五对持久的雌性-雌性配对。我们发现，这些配对可以成功地以与雌性-雄性配对相当的方式养育后代。因此，同性性行为和雌性配对是推迟繁殖或独自繁殖而没有伴侣帮助的更好选择。相比之下，在雌性移除实验的情况下，雄性中的同性配对行为是一种暂时现象，具有特征性的相互攻击。此外，在雄性偏性比的情况下，我们观察到了父子和父女交配。据我们所知，这些结果是在控制实验条件下首次获得的，证明了种群的性别比例可以改变社会结构，并导致在一夫一妻制物种中出现合作的同性繁殖行为。
