Bulgarella Mariana, Trewick Steven A, Godfrey A Jonathan R, Sinclair Brent J, Morgan-Richards Mary
Ecology Group, Institute of Agriculture and Environment, Massey University, Private Bag 11-222, Palmerston North 4442, New Zealand.
Institute of Fundamental Sciences, Massey University, Private Bag 11-222, Palmerston North 4442, New Zealand.
J Insect Physiol. 2015 Apr;75:30-8. doi: 10.1016/j.jinsphys.2015.02.012. Epub 2015 Mar 6.
Populations of the same species inhabiting distinct localities experience different ecological and climatic pressures that might result in differentiation in traits, particularly those related to temperature. We compared metabolic rate (and its thermal sensitivity), growth rate, and body size among nine high- and low-elevation populations of the Wellington tree weta, Hemideina crassidens, distributed from 9 to 1171 m a.s.l across New Zealand. Our results did not indicate elevational compensation in metabolic rates (metabolic cold adaptation). Cold acclimation decreased metabolic rate compared to warm-acclimated individuals from both high- and low-elevation populations. However, we did find countergradient variation in growth rates, with individuals from high-elevation populations growing faster and to a larger final size than individuals from low-elevation populations. Females grew faster to a larger size than males, although as adults their metabolic rates did not differ significantly. The combined physiological and morphological data suggest that high-elevation individuals grow quickly and achieve larger size while maintaining metabolic rates at levels not significantly different from low-elevation individuals. Thus, morphological differentiation among tree weta populations, in concert with genetic variation, might provide the material required for adaptation to changing conditions.
生活在不同地区的同一物种群体面临着不同的生态和气候压力，这可能导致性状分化，尤其是与温度相关的性状。我们比较了分布在新西兰海拔9至1171米的9个高海拔和低海拔的威灵顿树螽（Hemideina crassidens）群体的代谢率（及其热敏感性）、生长率和体型。我们的结果并未表明代谢率存在海拔补偿（代谢冷适应）。与来自高海拔和低海拔群体的温暖驯化个体相比，冷驯化降低了代谢率。然而，我们确实发现了生长率的反梯度变化，高海拔群体的个体比低海拔群体的个体生长得更快，最终体型也更大。雌性比雄性生长得更快，体型也更大，尽管成年后它们的代谢率没有显著差异。综合生理和形态学数据表明，高海拔个体生长迅速，体型较大，同时将代谢率维持在与低海拔个体无显著差异的水平。因此，树螽群体之间的形态分化，与遗传变异一起，可能为适应不断变化的环境提供所需的物质基础。
