Charbonnier Julie F, Vonesh James R
Department of Biology, Virginia Commonwealth University , Richmond, VA , USA.
PeerJ. 2015 Sep 22;3:e1268. doi: 10.7717/peerj.1268. eCollection 2015.
Many animals with complex life cycles can cope with environmental uncertainty by altering the timing of life history switch points through plasticity. Pond hydroperiod has important consequences for the fitness of aquatic organisms and many taxa alter the timing of life history switch points in response to habitat desiccation. For example, larval amphibians can metamorphose early to escape drying ponds. Such plasticity may induce variation in size and morphology of juveniles which can result in carry-over effects on jumping performance. To investigate the carry-over effects of metamorphic plasticity to pond drying, we studied the Túngara frog, Physalaemus pustulosus, a tropical anuran that breeds in highly ephemeral habitats. We conducted an outdoor field mesocosm experiment in which we manipulated water depth and desiccation and measured time and size at metamorphosis, tibiofibula length and jumping performance. We also conducted a complimentary laboratory experiment in which we manipulated resources, water depth and desiccation. In the field experiment, metamorphs from dry-down treatments emerged earlier, but at a similar size to metamorphs from constant depth treatments. In the laboratory experiment, metamorphs from the low depth and dry-down treatments emerged earlier and smaller. In both experiments, frogs from dry-down treatments had relatively shorter legs, which negatively impacted their absolute jumping performance. In contrast, reductions in resources delayed and reduced size at metamorphosis, but had no negative effect on jumping performance. To place these results in a broader context, we review past studies on carry-over effects of the larval environment on jumping performance. Reductions in mass and limb length generally resulted in lower jumping performance across juvenile anurans tested to date. Understanding the consequences of plasticity on size, morphology and performance can elucidate the linkages between life stages.
许多具有复杂生命周期的动物可以通过可塑性来改变生活史转换点的时间，从而应对环境的不确定性。池塘积水期对水生生物的适合度有重要影响，许多分类群会响应栖息地干涸而改变生活史转换点的时间。例如，两栖类幼体可以提前变态以逃离干涸的池塘。这种可塑性可能会导致幼体的大小和形态发生变化，进而对跳跃性能产生遗留效应。为了研究变态可塑性对池塘干涸的遗留效应，我们研究了泡蟾，一种在高度短暂的栖息地繁殖的热带无尾目动物。我们进行了一项室外田间中宇宙实验，在实验中我们控制水深和干涸情况，并测量变态时的时间和大小、胫腓骨长度以及跳跃性能。我们还进行了一项补充实验室实验，在实验中我们控制资源、水深和干涸情况。在田间实验中，干涸处理组的变态个体出现得更早，但大小与恒深处理组变态个体相似。在实验室实验中，低水深和干涸处理组的变态个体出现得更早且更小。在两个实验中，干涸处理组的青蛙腿部相对较短，这对它们的绝对跳跃性能产生了负面影响。相比之下，资源减少会延迟变态并减小变态时的大小，但对跳跃性能没有负面影响。为了将这些结果置于更广泛的背景下，我们回顾了过去关于幼体环境对跳跃性能遗留效应的研究。到目前为止，在测试的幼年无尾目中，体重和肢体长度的减少通常会导致跳跃性能下降。了解可塑性对大小、形态和性能的影响可以阐明生命阶段之间的联系。
