Le Gall Marion, Word Mira L, Beye Alioune, Cease Arianne J
School of Sustainability, Arizona State University, Tempe, AZ, United States.
Direction de la Protection des Végétaux, Nganda, Senegal.
Curr Res Insect Sci. 2020 Nov 4;1:100004. doi: 10.1016/j.cris.2020.100004. eCollection 2021.
There is generally a close relationship between a consumer's food and its optimal nutrients. When there is a mismatch, it is hypothesized that mobile herbivores switch between food items to balance nutrients, however, there are limited data for field populations. In this study, we measured ambient plant nutrient content at two time points and contrasted our results with the nutrient ratio selected by wild female and male grasshoppers (). Few plants were near optimal protein:carbohydrate ratio (P:C), nor were plants complementary. Grasshoppers collected earlier all regulated for a carbohydrate-biased ratio but females ate slightly more protein. We hypothesized that the long migration undertaken by this species may explain its carbohydrate needs. In contrast to most laboratory studies, grasshoppers collected later did not tightly regulate their P:C. These results suggest that field populations are not shifting their P:C to match seasonal plant nutrient shifts and that mobile herbivores rely on post-ingestive mechanisms in the face of environmental variation. Because this is among the first studies to examine the relationship between ambient nutrient landscape and physiological state our data are a key step in bridging knowledge acquired from lab studies to hypotheses regarding the role ecological factors play in foraging strategies.
一般来说，消费者所食用的食物与其最佳营养成分之间存在密切关系。当出现不匹配情况时，据推测，移动性食草动物会在不同食物间切换以平衡营养，但针对野外种群的数据有限。在本研究中，我们在两个时间点测量了周围植物的营养成分，并将我们的结果与野生雌性和雄性蚱蜢（）选择的营养比例进行了对比。很少有植物接近最佳蛋白质：碳水化合物比例（P:C），而且植物之间也不具有互补性。早期采集的蚱蜢都将其比例调节为偏向碳水化合物，但雌性摄入的蛋白质略多。我们推测，该物种进行的长距离迁徙可能解释了其对碳水化合物的需求。与大多数实验室研究不同的是，后期采集的蚱蜢并没有严格调节它们的P:C。这些结果表明，野外种群不会改变它们的P:C来匹配季节性植物营养变化，并且移动性食草动物在面对环境变化时依赖于摄食后机制。由于这是首批研究周围营养环境与生理状态之间关系的研究之一，我们的数据是将从实验室研究中获得的知识与关于生态因素在觅食策略中所起作用的假设联系起来的关键一步。
