Miller Gabriel A, Clissold Fiona J, Mayntz David, Simpson Stephen J
School of Biological Sciences, The University of Sydney, Heydon-Laurence Building A08, NSW 2006, Australia.
Proc Biol Sci. 2009 Oct 22;276(1673):3581-9. doi: 10.1098/rspb.2009.1030. Epub 2009 Jul 22.
Ectotherms have evolved preferences for particular body temperatures, but the nutritional and life-history consequences of such temperature preferences are not well understood. We measured thermal preferences in Locusta migratoria (migratory locusts) and used a multi-factorial experimental design to investigate relationships between growth/development and macronutrient utilization (conversion of ingesta to body mass) as a function of temperature. A range of macronutrient intake values for insects at 26, 32 and 38 degrees C was achieved by offering individuals high-protein diets, high-carbohydrate diets or a choice between both. Locusts placed in a thermal gradient selected temperatures near 38 degrees C, maximizing rates of weight gain; however, this enhanced growth rate came at the cost of poor protein and carbohydrate utilization. Protein and carbohydrate were equally digested across temperature treatments, but once digested both macronutrients were converted to growth most efficiently at the intermediate temperature (32 degrees C). Body temperature preference thus yielded maximal growth rates at the expense of efficient nutrient utilization.
变温动物已经进化出对特定体温的偏好，但这种温度偏好对营养和生活史的影响尚未得到充分理解。我们测量了飞蝗（Locusta migratoria）的热偏好，并采用多因素实验设计来研究生长/发育与常量营养素利用（摄入物转化为体重）之间的关系，该关系是温度的函数。通过为个体提供高蛋白饮食、高碳水化合物饮食或两者之间的选择，实现了昆虫在26、32和38摄氏度下的一系列常量营养素摄入量值。置于热梯度中的蝗虫选择了接近38摄氏度的温度，从而使体重增加率最大化；然而，这种生长率的提高是以蛋白质和碳水化合物利用不佳为代价的。在不同温度处理下，蛋白质和碳水化合物的消化程度相同，但一旦消化，这两种常量营养素在中间温度（32摄氏度）下转化为生长的效率最高。因此，体温偏好以有效营养利用为代价产生了最大生长率。
