公綠頭鴨（Anas platyrhynchos,，如上圖）因其長而螺旋的生殖器聞名天下,。
如今,，科學(xué)家發(fā)現(xiàn),，它們還有其他一些值得炫耀的東西,。將綠頭鴨的精液與一種常見細(xì)菌——大腸桿菌混合在一起，研究人員注意到,，這些鴨子的精液能夠殺死細(xì)菌,。
研究人員在4月12日的《生物學(xué)快報(bào)》網(wǎng)絡(luò)版上報(bào)告說，那些喙更加華美的公鴨的精液具有最強(qiáng)的抗菌能力,，所消滅的細(xì)菌是長著暗淡的喙的公鴨的3倍,。
這些發(fā)現(xiàn)表明，母綠頭鴨被色彩鮮艷的公鴨所吸引并非僅僅因?yàn)楹笳吒悠G俗,，還緣于它們?cè)诮慌溥^程中僅會(huì)傳播較少的細(xì)菌,。（生物谷Bioon.com）
生物谷推薦原文出處：
Biol. Lett. doi: 10.1098/rsbl.2011.0276
Sexual ornamentation reflects antibacterial activity of ejaculates in mallards
Melissah Rowe1,2,*, Gábor árpád Czirják3, Kevin J. McGraw1 and Mathieu Giraudeau1
Abstract
Bacteria present in ejaculates can impair sperm function and reduce male reproductive success. Thus, selection should favour the evolution of antimicrobial defences to limit the detrimental effects of sperm-associated bacteria. Additionally, current hypotheses suggest that ornamental traits may signal information about the infection status of an individual or the ability of an individual to resist bacterial-induced sperm damage. However, despite the evolutionary implications of ejaculate antimicrobials, and the putative importance of pathogens for the evolution of male ornamentation, tests of these hypotheses are lacking. We examined the antibacterial activity of semen from mallard ducks (Anas platyrhynchos) and tested whether the bactericidal capacity of semen was associated with bill coloration, a sexually selected trait. We show that mallard semen exhibits significant antibacterial activity, as measured by the in vitro capacity to kill Escherichia coli and Staphylococcus aureus. Furthermore, we demonstrate that males with more colourful bills have semen with superior bacterial-killing ability. These results suggest that females could use male phenotypic traits to avoid sexually transmitted pathogens and acquire partners whose sperm suffer less bacteria-induced damage.
