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首页> 外文期刊>The Royal Society Proceedings B: Biological Sciences >A neotropical forest bird can measure the slight changes in tropical photoperiod
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A neotropical forest bird can measure the slight changes in tropical photoperiod

机译：新型热带森林鸟类可以测量热带光周期的细微变化

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Many tropical birds breed seasonally, but it is largely unknown which environmental cues they use to time reproduction. Changes in tropical photoperiod have been regarded as too small to be used as a proximate environmental cue. This hypothesis, however, has never been rigorously tested. Here, we report on experimental evidence that photoperiodic changes characteristic of tropical latitudes stimulate reproductive activity in a neotropical bird from the forest understory. In the central Republic of Panama (9 degrees N), photoperiod varies annually between 12 hours (December) and 13 hours (June). Free-living spotted antbirds (Hylophylax n. naevioides) had regressed gonads in December, but increased gonads ahead of the rainy (the breeding) season in May Captive spotted antbirds exposed to a 'long' photoperiod of 13 hours increased gonadal size eight-fold and song activity six-fold over that of control birds remaining on a simulated 'short' photoperiod of 12 hours of daylight. Moreover, even a photoperiod of 12 hours 17 minutes was sufficient to stimulate gonadal growth in photostimulated birds over that of controls. The dramatic changes in gonadal development were not accompanied by similar changes in hormone titres such as luteinizing hormone and testosterone as expected from temperate zone birds. We propose a more general role of the tropical photoperiod in the regulation of seasonal events in tropical organisms, or in temperate zone species migrating to the tropics. [References: 61]
机译：许多热带鸟类都按季节繁殖，但很大程度上未知它们使用哪种环境线索来进行繁殖。热带光周期的变化被认为太小而不能用作近乎环境的线索。但是，这一假设从未经过严格的检验。在这里，我们报告的实验证据表明，热带纬度的光周期变化会刺激来自森林底层的新热带鸟类的生殖活动。在巴拿马中部共和国（北纬9度），光周期每年在12个小时（12月）和13个小时（6月）之间变化。自由活动的有斑点的蚂蚁（Hylophylax n。naevioides）在12月已经消灭了性腺，但是在5月的雨季（繁殖）之前，性腺的数量增加了。圈养的有斑点的蚂蚁暴露于13小时的“长”光周期，使性腺大小增加了八倍。和歌曲活动是在模拟的“短时间”日光下12小时的光照下，对照鸟类的活动量的六倍。而且，即使是12小时17分钟的光照周期也足以刺激光刺激鸟的性腺生长，而对照则不然。性腺发育的剧烈变化并没有伴随温带区鸟类所预期的类似激素含量的变化，例如黄体生成激素和睾丸激素。我们提出热带光周期在调节热带生物或向热带地区迁移的温带物种中的季节性事件中具有更一般的作用。 [参考：61]

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