Stillwell R Craig, Wallin William G, Hitchcock Lisa J, Fox Charles W
Department of Entomology, University of Kentucky, S225 Agricultural Science Center North, Lexington, KY 40546-0091, USA.
Oecologia. 2007 Aug;153(2):309-21. doi: 10.1007/s00442-007-0748-5. Epub 2007 May 8.
Most studies of phenotypic plasticity investigate the effects of an individual environmental factor on organism phenotypes. However, organisms exist in an ecologically complex world where multiple environmental factors can interact to affect growth, development and life histories. Here, using a multifactorial experimental design, we examine the separate and interactive effects of two environmental factors, rearing host species (Vigna radiata, Vigna angularis and Vigna unguiculata) and temperature (20, 25, 30 and 35 degrees C), on growth and life history traits in two populations [Burkina Faso (BF) and South India (SI)] of the seed beetle, Callosobruchus maculatus. The two study populations of beetles responded differently to both rearing host and temperature. We also found a significant interaction between rearing host and temperature for body size, growth rate and female lifetime fecundity but not larval development time or larval survivorship. The interaction was most apparent for growth rate; the variance in growth rate among hosts increased with increasing temperature. However, the details of host differences differed between our two study populations; the degree to which V. unguiculata was a better host than V. angularis or V. radiata increased at higher temperatures for BF beetles, whereas the degree to which V. unguiculata was the worst host increased at higher temperatures for SI beetles. We also found that the heritabilities of body mass, growth rate and fecundity were similar among rearing hosts and temperatures, and that the cross-temperature genetic correlation was not affected by rearing host, suggesting that genetic architecture is generally stable across rearing conditions. The most important finding of our study is that multiple environmental factors can interact to affect organism growth, but the degree of interaction, and thus the degree of complexity of phenotypic plasticity, varies among traits and between populations.
大多数关于表型可塑性的研究都探究了单个环境因素对生物体表型的影响。然而，生物体存在于一个生态复杂的世界中，多种环境因素可能相互作用，从而影响生长、发育和生活史。在此，我们采用多因素实验设计，研究了两种环境因素，即饲养寄主物种（绿豆、赤豆和豇豆）和温度（20、25、30和35摄氏度）对豆象Callosobruchus maculatus两个种群[布基纳法索（BF）和印度南部（SI）]的生长和生活史特征的单独影响及交互作用。这两个甲虫研究种群对饲养寄主和温度的反应各不相同。我们还发现，饲养寄主和温度对体型、生长速率和雌虫终生繁殖力存在显著交互作用，但对幼虫发育时间或幼虫存活率没有影响。这种交互作用在生长速率方面最为明显；寄主间生长速率的差异随温度升高而增加。然而，我们两个研究种群中寄主差异的细节有所不同；对于BF种群的甲虫，在较高温度下，豇豆作为比赤豆或绿豆更好寄主的程度增加，而对于SI种群的甲虫，在较高温度下，豇豆作为最差寄主的程度增加。我们还发现，在不同的饲养寄主和温度条件下，体重、生长速率和繁殖力的遗传力相似，并且跨温度的遗传相关性不受饲养寄主的影响，这表明遗传结构在不同饲养条件下总体上是稳定的。我们研究中最重要的发现是，多种环境因素可以相互作用来影响生物体的生长，但相互作用的程度，以及表型可塑性的复杂程度，在不同性状和不同种群之间存在差异。
