McManus M G, Travis J
Department of Biological Science, Florida State University, Tallahassee, FL 33206-2043, USA, , , , , , US.
Oecologia. 1998 Apr;114(3):317-325. doi: 10.1007/s004420050453.
While the life history traits of animals usually exhibit substantial phenotypic plasticity, such plasticity might reflect either a simple alteration in the level of energy accrual and use or a genuine shift in energy allocation tactics between environmental conditions. The latter would represent genuine plasticity in the life history itself, and thus it is important to distinguish which of these two processes underlies the observed plasticity of life history traits. We investigated this issue by examining the effects of temperature and salinity variation during ontogeny on the allocation of biomass and lipid storage in male sailfin mollies, Poecilia latipinna. We raised males from four natural populations from birth to maturity in controlled laboratory conditions. Neither distinct temperatures (23 or 29°C) nor different salinity regimes (2, 12, or 20 parts per thousand) affected body mass, although males from different populations differed substantially in body mass. However, males raised at the higher temperature had a greater allocation of biomass to testis and a lower allocation to viscera mass. The amount of stored lipid was altered by temperature variation but the direction and magnitude of the effect varied substantially among males from the different populations. Salinity variation affected neither biomass allocation nor the level of lipid storage. These results indicate that male mollies possess a flexible developmental program with respect to temperature that canalizes body size and alters the allocation of biomass among competing demands for reproductive readiness and capacity for energy storage.
虽然动物的生活史特征通常表现出显著的表型可塑性，但这种可塑性可能反映的要么是能量积累和利用水平的简单改变，要么是环境条件之间能量分配策略的真正转变。后者将代表生活史本身的真正可塑性，因此区分这两个过程中的哪一个是观察到的生活史特征可塑性的基础很重要。我们通过研究雄性帆鳍鳉（Poecilia latipinna）个体发育过程中温度和盐度变化对生物量分配和脂质储存的影响来探讨这个问题。我们在可控的实验室条件下将来自四个自然种群的雄性个体从出生饲养至成熟。尽管来自不同种群的雄性个体在体重上有很大差异，但不同的温度（23或29°C）和不同的盐度条件（千分之二、千分之十二或千分之二十）均未影响体重。然而，在较高温度下饲养的雄性个体将更多的生物量分配给了睾丸，而分配给内脏的生物量较少。储存脂质的量因温度变化而改变，但不同种群雄性个体的影响方向和程度差异很大。盐度变化既不影响生物量分配，也不影响脂质储存水平。这些结果表明，雄性帆鳍鳉在温度方面具有灵活的发育程序，该程序使体型固定，并改变了在生殖准备和能量储存能力的竞争需求之间的生物量分配。
