【生態】フラミンゴの性的誇示の複雑度

The degree of complexity in sexual displays performed by wild flamingos may influence the likelihood that they will breed, according to a paper in Scientific Reports this week.

Although flamingos are socially monogamous, pairs only bond for a single breeding season. This means that all sexually mature individuals are involved in group displays each year in order to find a new mate, with varying degrees of success.

Charlotte Perrot and colleagues investigated variations in sexual display complexity (SDC) in wild flamingos aged between four and 37 years old. By observing 100 flamingos individually in five minute courtship sequences, the authors calculated the complexity of displays based on the number of different postures used (ranging from two to eight) and the number of transitions between postures (between two and 17).

The authors found that a high level of SDC increased the probability of a flamingo becoming a breeding individual (i.e. by attracting a partner). They suggest that high SDC in flamingos signals individual quality, which may in turn indicate a superior competitive ability to secure a nest site. The authors also observed that as flamingos got older, SDC increased until around 20 years old, after which display complexity declined. The authors suggest that an increase in SDC may be due to improved motor performance as the flamingos mature, while the decrease after the age of 20 may reflect reproductive decline.