Bradshaw William E
Department of Biology, University of Oregon, 97403, Eugene, OR, USA.
Oecologia. 1980 Jul;46(1):13-17. doi: 10.1007/BF00346959.
Wyeomyia smithii Coq. (Diptera: Culicidae) completes its pre-adult development only within leaves of the purple pitcher-plant, Sarracenia purpurea. Between early June and mid-October in northern New York State, the daily temperature cycle in leaves lagged the photic cycle by 0-6 h and exhibited a mean daily amplitude of 14.5°C.Thermoperiod acts as a potent zeitgeber. At constant temperatures, W. smithii respond to the shorter dark period of a symmetric skeleton photoperiod as "day". However, a superimposed thermoperiod having the thermophase coincident with the longer dark period overrides this tendancy. Thermoperiods may also perturb the photoperiodic clock but W. smithii compensate for the range of phase relationships between the photic and thermal cycles observed in nature.Compared with constant temperatures, W. smithii develop more slowly but exhibit a 7-fold increase in fecundity when reared under fluctuating temperatures. The net result is a 50% greater capacity for increase in the latter regimen. These results suggest that maximum fitness in W. smithii is achieved through the action of, and not despite, thermal heterogeneity.
史密斯摇蚊（双翅目：蚊科）仅在紫瓶子草（Sarracenia purpurea）的叶片内完成其成虫前期发育。在纽约州北部，6月初至10月中旬期间，叶片内的每日温度循环比光照循环滞后0 - 6小时，且日平均振幅为14.5°C。热周期起着强大的授时因子作用。在恒温条件下，史密斯摇蚊将对称骨架光周期中较短的暗期视为“白天”。然而，热期与较长暗期重合的叠加热周期会推翻这种倾向。热周期也可能干扰光周期时钟，但史密斯摇蚊能补偿在自然界中观察到的光周期和热周期之间的相位关系范围。与恒温条件相比，史密斯摇蚊在温度波动条件下饲养时发育较慢，但繁殖力提高了7倍。最终结果是后一种饲养方式下种群增长能力提高了50%。这些结果表明，史密斯摇蚊的最大适合度是通过热异质性的作用实现的，而非不受其影响。
