Coppack Timothy, Pulido Francisco, Czisch Michael, Auer Dorothee P, Berthold Peter
Max Planck Research Centre for Ornithology, Andechs & Radolfzell, Vogelwarte Radolfzell, 78315 Radolfzell, Germany.
Proc Biol Sci. 2003 Aug 7;270 Suppl 1(Suppl 1):S43-6. doi: 10.1098/rsbl.2003.0005.
Recent climatic change is causing spring events in northern temperate regions to occur earlier in the year. As a result, migratory birds returning from tropical wintering sites may arrive too late to take full advantage of the food resources on their breeding grounds. Under these conditions, selection will favour earlier spring arrival that could be achieved by overwintering closer to the breeding grounds. However, it is unknown how daylength conditions at higher latitudes will affect the timing of life cycle stages. Here, we show in three species of Palaearctic-African migratory songbirds that a shortening of migration distance induces an advancement of springtime activities. Birds exposed to daylengths simulating migration to and wintering in southern Europe considerably advanced their spring migratory activity and testicular development. This response to the novel photoperiodic environment will enable birds wintering further north to advance spring arrival and to start breeding earlier. Thus, phenotypic flexibility in response to the photoperiod may reinforce selection for shorter migration distance if spring temperatures continue to rise.
近期的气候变化正导致北半球温带地区的春季活动在一年中更早发生。结果，从热带越冬地返回的候鸟可能到达得太晚，无法充分利用其繁殖地的食物资源。在这种情况下，自然选择将有利于更早的春季到达，这可以通过在更靠近繁殖地的地方越冬来实现。然而，高纬度地区的日照时长条件将如何影响生命周期各阶段的时间安排尚不清楚。在这里，我们在三种古北界-非洲迁徙鸣禽中发现，缩短迁徙距离会促使春季活动提前。暴露于模拟向欧洲南部迁徙和在欧洲南部越冬的日照时长下的鸟类，其春季迁徙活动和睾丸发育显著提前。这种对新光周期环境的反应将使在更北地区越冬的鸟类能够提前春季到达并更早开始繁殖。因此，如果春季气温持续上升，对光周期的表型灵活性可能会加强对较短迁徙距离的选择。
