Grover Crystal D, Kay Adam D, Monson Jessica A, Marsh Thomas C, Holway David A
Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA.
Proc Biol Sci. 2007 Dec 7;274(1628):2951-7. doi: 10.1098/rspb.2007.1065.
Predicting the outcome of competitive interactions is a fundamental goal in ecology. Ecological stoichiometry, which relates nutrient balance to ecological processes, provides a framework for identifying mechanistic links among macronutrient availability, nutritional physiology and competitive performance. Because carbohydrates serve as a principal metabolic fuel, carbohydrate scarcity may impinge upon behaviours affecting competitive dominance (e.g. aggression, activity) to a greater extent than deficiencies of protein or other nutrients used preferentially for growth. Here, we tested this prediction with a diet manipulation study involving laboratory colonies of Argentine ants (Linepithema humile), a widespread and aggressive invasive species. The availability of both sucrose and insect prey influenced brood production and worker survival after three months. However, colonies became less aggressive and less active only when deprived of sucrose (but not prey). Scarcity of sucrose (but not prey) was also associated with reduced fat mass in individual workers. These data provide the first experimental support that carbohydrate scarcity compromises aggression and activity in ants, and illustrate, in principle, how access to carbohydrate-rich resources (e.g. plant exudates, hemipteran honeydew) might influence behavioural investments that contribute to competitive performance. Such investments might be especially important for invasive ants, given their aggressiveness and tendency to interact with honeydew-producing Hemiptera.
预测竞争相互作用的结果是生态学的一个基本目标。生态化学计量学将营养平衡与生态过程联系起来，为确定大量营养素可利用性、营养生理学和竞争表现之间的机制联系提供了一个框架。由于碳水化合物是主要的代谢燃料，碳水化合物短缺可能比蛋白质或其他优先用于生长的营养素缺乏更严重地影响影响竞争优势的行为（如攻击性、活动）。在这里，我们通过一项饮食操纵研究验证了这一预测，该研究涉及阿根廷蚁（Linepithema humile）的实验室群体，这是一种广泛分布且具有攻击性的入侵物种。三个月后，蔗糖和昆虫猎物的可利用性都影响了幼虫的产生和工蚁的存活。然而，只有在缺乏蔗糖（而非猎物）时，蚁群的攻击性和活跃度才会降低。蔗糖短缺（而非猎物短缺）还与个体工蚁脂肪量减少有关。这些数据首次提供了实验支持，即碳水化合物短缺会损害蚂蚁的攻击性和活动，并从原则上说明了获取富含碳水化合物的资源（如植物分泌物、半翅目昆虫蜜露）如何可能影响有助于竞争表现的行为投入。鉴于入侵蚁的攻击性以及它们与产生蜜露的半翅目昆虫相互作用的倾向，这种投入可能对入侵蚁尤为重要。
