Abstract：
Environmental conditions like temperature and photoperiod can strongly shape organisms\' growth and development. For many ectotherms with complex life cycles, global change will cause their offspring to experience warmer conditions and earlier-season photoperiods, two variables that can induce conflicting responses. We experimentally manipulated photoperiod and temperature during gray treefrog (Hyla versicolor) larval development to examine effects at metamorphosis and during short (10-day) and long (56-day) periods post-metamorphosis. Both early- and late-season photoperiods (April and August) decreased age and size at metamorphosis relative to the average-season (June) photoperiod, while warmer temperatures decreased age but increased size at metamorphosis. Warmer larval temperatures reduced short-term juvenile growth but had no long-term effect. Conversely, photoperiod had no short-term carryover effect, but juveniles from early- and late-season larval photoperiods had lower long-term growth rates than juveniles from the average-season photoperiod. Similar responses to early- and late-season photoperiods may be due to reduced total daylight compared with average-season photoperiods. However, juveniles from late-season photoperiods selected cooler temperatures than early-season juveniles, suggesting that not all effects of photoperiod were due to total light exposure. Our results indicate that despite both temperature and photoperiod affecting metamorphosis, the long-term effects of photoperiod may be much stronger than those of temperature.
摘要：
温度和光周期等环境条件可以强烈影响生物的生长和发育。对于许多具有复杂生命周期的外热，全球变化将使他们的后代经历更温暖的条件和更早的光周期，两个变量可能会引发冲突的反应。我们通过实验操纵了灰色树蛙（Hylaversicolor）幼虫发育过程中的光周期和温度，以检查变态以及变态后的短时间（10天）和长时间（56天）的影响。相对于平均季节（6月）光周期，早期和后期的光周期（4月和8月）都降低了变态的年龄和大小，虽然温度升高降低了年龄，但在变态时尺寸增加。温暖的幼虫温度降低了短期的幼体生长，但没有长期影响。相反，光周期没有短期携带效应，但是早期和后期幼虫光周期的少年的长期增长率低于平均季节光周期的少年。与平均季节光周期相比，对早期和后期光周期的类似反应可能是由于总日光减少所致。然而,来自晚季节光周期的少年选择比早期季节少年更低的温度，这表明并非所有光周期的影响都是由于总的光照。我们的结果表明，尽管温度和光周期都会影响变态，光周期的长期影响可能比温度强得多。
