幼虫寄主植物质量与温度之间的相互作用会影响食草动物的短期生理速率和生活史特征。这些因素可以在局部变化,导致局部适应饮食和温度,但是很少进行群体之间这些相互作用的比较。在这项研究中,我们研究人工饮食的大量营养素比例如何决定幼虫的生长,发展,以及来自不同气候区的两个入侵北美种群在不同温度下的幼体菜鸟(鳞翅目:Pieridae)的存活。我们用三种温度处理(18°C,25°C,和32°C)和三种人工饮食处理在蛋白质与碳水化合物的比例方面有所不同(低蛋白,平衡,和高蛋白)。在较低的温度下,饮食对生活史特征的影响更大,但是这些在不同的人群之间是不同的。在低温处理下,亚热带种群的幼虫在低蛋白饮食下的成活率降低,而温带种群的幼虫存活率在所有温度和饮食治疗中都同样高。总的来说,这两个群体的表现都更差(即,他们表现出较慢的消费率,增长,和发展,并且在饮食中具有较小的p质量),蛋白质比例低,但是在所有温度下,温带种群的幼虫对饮食比例变化的敏感性较低。我们的结果证实,昆虫食草动物营养不平衡的生理和生活史后果可能取决于发育温度,北美不同地理种群对营养平衡和温度的敏感性不同。
The interaction between larval host plant quality and temperature can influence the short-term physiological rates and life-history traits of insect herbivores. These factors can vary locally, resulting in local adaptation in responses to diet and temperature, but the comparison of these interactions between populations is infrequently carried out. In this study, we examine how the macronutrient ratio of an artificial diet determines the larval growth, development, and survival of larval Pieris rapae (Lepidoptera: Pieridae) at different temperatures between two invasive North American populations from different climatic regions. We conducted a fully factorial experiment with three temperature treatments (18°C, 25°C, and 32°C) and three artificial diet treatments varying in terms of the ratio of protein to carbohydrate (low protein, balanced, and high protein). The effects of diet on life-history traits were greater at lower temperatures, but these differed between populations. Larvae from the subtropical population had reduced survival to pupation on the low-protein diet in the cold temperature treatment, whereas larval survival for the temperate population was equally high for all temperature and diet treatments. Overall, both populations performed more poorly (i.e., they showed slower rates of consumption, growth, and development, and had a smaller pupal mass) in the diet with the low protein ratio, but larvae from the temperate population were less sensitive to diet ratio changes at all temperatures. Our results confirm that the physiological and life-history consequences of imbalanced nutrition for insect herbivores may depend on developmental temperatures, and that different geographic populations of P. rapae within North America vary in their sensitivity to nutritional balance and temperature.