Kingsolver Joel G
Department of Zoology, NJ-15, University of Washington, Seattle, Washington, 98195.
Evolution. 1995 Oct;49(5):942-954. doi: 10.1111/j.1558-5646.1995.tb02329.x.
The western white butterfly, Pontia occidentalis, has distinctly different wing phenotypes during spring and summer generations as a result of phenotypic plasticity (seasonal polyphenism). We experimentally generated different seasonal phenotypes in the lab by altering photoperiodic conditions during rearing, and released the resulting butterflies in the field. Mark-recapture studies were then used to estimate the effects of the polyphenism on activity patterns and adult survival in both late-spring (one study) and summer (two studies) conditions. There were no significant effects of rearing treatment on temporal patterns of behavioral activity during either the late-spring or the summer field studies. Recapture probabilities were consistently higher for males than females in all three field studies; in the summer 1992 study, recapture probabilities were higher for long-day (LD) than for short-day (SD) treatment groups. During the late-spring 1992 study, there were no significant differences between LD and SD treatment groups for survival probabilities. In the two summer studies, there were significant effects of photoperiodic treatment on survival probabilities; in the summer 1992 study, LD individuals consistently had higher survival probabilities than SD individuals; in the summer 1991 study, there was a significant interaction between treatment and time period on survival probabilities, such that survival probabilities were higher for LD than for SD individuals in two of four time periods. The consistent differences in survival probabilities between treatment groups in the summer 1992 study can be accounted for by the differences in wing traits between the treatment groups. Micrometeorological data from the study site showed that midday ambient temperatures averaged ~3°C hotter during the 1992 than the 1991 summer study and that ambient conditions during the late-spring 1992 study were relatively warm and sunny for the season. These results document the varying relationships between phenotype and fitness in the temporally fluctuating environments experienced by this population.
西部白蝴蝶（Pontia occidentalis）由于表型可塑性（季节性多型现象），在春季和夏季世代具有明显不同的翅表型。我们通过在饲养过程中改变光周期条件，在实验室中实验性地产生了不同的季节表型，并将由此产生的蝴蝶放归野外。然后，通过标记重捕研究来估计多型现象对春末（一项研究）和夏季（两项研究）条件下活动模式和成虫存活率的影响。在春末或夏季的野外研究中，饲养处理对行为活动的时间模式均无显著影响。在所有三项野外研究中，雄性的重捕概率始终高于雌性；在1992年夏季的研究中，长日照（LD）处理组的重捕概率高于短日照（SD）处理组。在1992年春末的研究中，LD和SD处理组的存活率没有显著差异。在两项夏季研究中，光周期处理对存活率有显著影响；在1992年夏季的研究中，LD个体的存活率始终高于SD个体；在1991年夏季的研究中，处理和时间段对存活率有显著的交互作用，使得在四个时间段中的两个时间段内，LD个体的存活率高于SD个体。1992年夏季研究中处理组之间存活率的持续差异可以通过处理组之间翅特征的差异来解释。研究地点的微气象数据表明，1992年夏季中午的环境温度平均比1991年夏季高约3°C，并且1992年春末研究期间的环境条件对于该季节来说相对温暖且阳光充足。这些结果记录了该种群在随时间波动的环境中表型与适合度之间不断变化的关系。
