Data from: Adaptive contraction of diet breadth affects sexual maturation and specific nutrient consumption in an extreme generalist omnivore

Animals balance their intake of specific nutrients, but little is known about how they do so when foraging in an environment with toxic resources and whether toxic foods promote adaptations that affect life history traits. In German cockroach (Blattella germanica) populations, glucose aversion has evolved in response to glucose-containing insecticidal baits. We restricted newly eclosed glucose averse (GA) and wild type (WT) female cockroaches to nutritionally defined diets varying in protein-to-carbohydrate (P:C) ratio (3:1, 1:1, or 1:3) or gave them free choice of the 3:1 and 1:3 diets, with either glucose or fructose as the sole carbohydrate source. We measured consumption of each diet over six days and then dissected the females to measure the length of basal oocytes in their ovaries. Our results showed significantly lower consumption by GA compared to WT cockroaches when restricted to glucose-containing diets, but also lower fructose intake by GA compared to WT cockroaches when restricted to high fructose diets or given choice of fructose-containing diets. Protein intake was regulated tightly regardless of carbohydrate intake, except by GA cockroaches restricted to glucose-containing diets. Oocyte growth was completely suppressed in GA females restricted to glucose-containing diets, but also significantly slower in GA than in WT females restricted to fructose-containing diets. Our findings suggest that GA cockroaches have adapted to reduced diet breadth through endocrine adjustments which reduce requirements for energetic fuels. Our study illustrates how an evolutionary change in the chemosensory system may affect the evolution of other traits that govern animal life histories.

动物会精准平衡特定营养物质的摄入，但目前学界对其在含有有毒资源的环境中觅食时如何实现这一平衡，以及有毒食物是否会推动产生影响动物生活史特征的适应性演化，仍所知有限。在德国小蠊（Blattella germanica）种群中，针对含葡萄糖的杀虫饵剂，已演化出葡萄糖拒食行为。我们将刚羽化的葡萄糖拒食型（glucose averse, GA）与野生型（wild type, WT）雌性德国小蠊分为两组：一组被限制喂食营养成分明确的日粮，这些日粮的蛋白质与碳水化合物（protein-to-carbohydrate, P:C）比例分别为3:1、1:1或1:3；另一组则可自由选择3:1与1:3比例的日粮，且两类日粮均以葡萄糖或果糖作为唯一碳水化合物来源。我们连续六天测定每类日粮的进食量，随后解剖雌性个体以测量其卵巢内基生卵母细胞的长度。实验结果显示，当被限制喂食含葡萄糖的日粮时，GA型德国小蠊的进食量显著低于WT型个体；而当被限制喂食高果糖日粮，或是可选择含果糖的日粮时，GA型个体的果糖摄入量同样显著低于WT型。除被限制喂食含葡萄糖日粮的GA型个体外，无论碳水化合物摄入情况如何，德国小蠊的蛋白质摄入均受到严格调控。被限制喂食含葡萄糖日粮的GA型雌性个体，其卵母细胞生长完全受到抑制；而被限制喂食含果糖日粮的GA型个体，其卵母细胞生长速度也显著慢于WT型个体。我们的研究结果表明，GA型德国小蠊通过内分泌调节降低了对能量燃料的需求，从而适应了食谱范围的缩减。本研究阐明了化学感受系统的演化改变，如何影响调控动物生活史的其他特征的演化。