Markman Shai, Leitner Stefan, Catchpole Clive, Barnsley Sara, Müller Carsten T, Pascoe David, Buchanan Katherine L
School of Biosciences, Cardiff University, Cardiff, United Kingdom.
PLoS One. 2008 Feb 27;3(2):e1674. doi: 10.1371/journal.pone.0001674.
Environmental pollutants which alter endocrine function are now known to decrease vertebrate reproductive success. There is considerable evidence for endocrine disruption from aquatic ecosystems, but knowledge is lacking with regard to the interface between terrestrial and aquatic ecosystems. Here, we show for the first time that birds foraging on invertebrates contaminated with environmental pollutants, show marked changes in both brain and behaviour. We found that male European starlings (Sturnus vulgaris) exposed to environmentally relevant levels of synthetic and natural estrogen mimics developed longer and more complex songs compared to control males, a sexually selected trait important in attracting females for reproduction. Moreover, females preferred the song of males which had higher pollutant exposure, despite the fact that experimentally dosed males showed reduced immune function. We also show that the key brain area controlling male song complexity (HVC) is significantly enlarged in the contaminated birds. This is the first evidence that environmental pollutants not only affect, but paradoxically enhance a signal of male quality such as song. Our data suggest that female starlings would bias their choice towards exposed males, with possible consequences at the population level. As the starling is a migratory species, our results suggest that transglobal effects of pollutants on terrestrial vertebrate physiology and reproduction could occur in birds.
现已知道，改变内分泌功能的环境污染物会降低脊椎动物的繁殖成功率。有大量证据表明水生生态系统存在内分泌干扰现象，但对于陆地生态系统与水生生态系统的交界处，我们却知之甚少。在此，我们首次表明，以受环境污染物污染的无脊椎动物为食的鸟类，其大脑和行为都出现了显著变化。我们发现，与对照雄性欧洲椋鸟（Sturnus vulgaris）相比，接触环境相关水平的合成雌激素和天然雌激素模拟物的雄性欧洲椋鸟，唱出的歌曲更长且更复杂，这是一种在吸引雌性进行繁殖方面很重要的性选择特征。此外，尽管经实验给药的雄性椋鸟免疫功能有所下降，但雌性椋鸟更喜欢接触污染物水平较高的雄性椋鸟的歌声。我们还表明，在受污染的鸟类中，控制雄性歌曲复杂性的关键脑区（HVC）明显增大。这是首个表明环境污染物不仅会影响，而且自相矛盾地会增强诸如歌声等雄性品质信号的证据。我们的数据表明，雌性椋鸟会偏向选择接触过污染物的雄性，这在种群层面可能会产生后果。由于椋鸟是一种迁徙物种，我们的研究结果表明，污染物对陆地脊椎动物生理和繁殖的全球影响可能会在鸟类身上出现。
