鸟儿有细菌吗(鸟儿为什么会有气味)

日期：2016-07-04 期刊：Science

鸟儿最让人喜欢的莫过于它们亮丽的羽毛、飞翔的能力和婉转的歌喉。然而，近日在英国奥斯汀举办的进化学会议上展示的一项研究则表明，细菌还让鸟儿拥有了另一项重要的特征：臭味。

气味一直排列在鸣禽的视觉和声音感觉之后，但是现在它已经成为日益被认可的鸣禽的一种重要感觉，譬如灯芯草雀对气味就不陌生。当普通的鸟儿清理它们的羽毛或是“打扮梳洗”时，它们的尾羽腺分泌的刺激气味会散布到全身。

这一行为对灯芯草雀吸引配偶非常重要：雌鸟雄鸟尾羽腺3种特殊气味的化学物质含量对繁殖具有重要意义——含有更浓雄性气味的鸟最终哺育的后代更多，含有雌性气味更浓的鸟也一样。

但灯芯草雀的气味来源并非单一的，其尾羽腺的很多化学物质是由细菌生成的。新的研究使鸟—细菌之间的关系更加确定。

当研究人员向灯芯草雀的尾羽腺注射抗体后，3种气味分子趋于减少，这3种气味分子正是让灯芯草雀“性感”的化学物质，美国密歇根大学的Danielle Whittaker说。所以，灯芯草雀似乎会基于细菌形成的气味，而不是自身产生的气味选择配偶。

原文链接：

Bacteria give bird its sexy smells

原文摘要：

Birds are perhaps best known for their bright colors, aerial prowess, and melodic songs. But research presented in Austin last week at the Evolution Conference shows that bacteria have granted some birds another important attribute: stink. Having long taken a back seat to sight and sound, scent is becoming more and more recognized as an important sense for songbirds, and dark-eyed juncos (Junco hyemalis, pictured) are no stranger to it. When these common birds clean their feathers—or preen—they spread pungent oil from their “preen glands” all over their bodies. The act is important for enticing mates: Three of the gland’s smelly chemicals are found in very different quantities in the two sexes, and males with a more masculine musk end up with more offspring. Females with a more feminine scent profile are more successful, too. But juncos likely aren’t making their perfume alone: Lots of those preen gland chemicals are naturally made by bacteria. And new work is making the bird-bacteria link even more firm. When researchers inject antibiotics into the juncos’ preen glands, the concentrations of three smelly molecules tend to decrease—the same three molecules that juncos find sexy in the right proportions, Danielle Whittaker of Michigan State University in East Lansing told attendees. So it seems like juncos may actually be picking mates based on their bacterial—rather than self-produced—body odor, a first for birds.