First larval stages require adequate feeding to reach subsequent instars. However, the accumulation of reserves is also important in the last larval instar because it is vital to pupate and successfully perform metamorphosis into adulthood. We indirectly determined the presence of changes in the relative importance of prey capture through larval ontogeny in the antlion larvae (Neuroptera Myrmeleontidae), a sit-and-wait predator with three instar stages that capture preys that fall into their pit-traps. We used scaling relationships between the size of body parts directly related to prey capture (prothorax) versus those that are not (thorax + abdomen). The prothorax (neck, head, and mandibles) is used in the pit building, prey capture, and re-capture, and pit cleaning. We measured the body parts of 70 larvae of Myrmeleon crudelis in a tropical rain forest of Costa Rica. The prothorax showed negative allometry: it was proportionally larger in the first than in the last instars. These results support the growth hypothesis, which states that food acquisition is key in the earlier stages of larval development. First instars can be more food-limited than later instars because they build small pit-traps where only very small arthropods can fall; have smaller mandibles and relatively lower grab force, increasing the probability of the prey escaping; and have smaller fat reserves and thus, are unable to resist long periods of starvation. This illustrates the relevance of using scaling relationships to better understand how ecological pressures change along ontogeny, emphasizing the role of food acquisition at earlier ontogenetic stages

幼虫的第一个阶段需要足够的饲料才能到达随后的龄期。然而，储备的积累在最后的幼虫龄期也很重要，因为化蛹并成功地进行变态进入成年期至关重要。我们通过蚁狮幼虫（Neuroptera Myrmeleontidae）的幼虫个体发育间接确定了猎物捕获相对重要性的变化，这是一种坐等捕食者，具有三个龄期，可以捕获落入陷阱的猎物。我们使用了与猎物捕获（前胸）直接相关的身体部位大小与与猎物无关（胸部 + 腹部）的身体部位大小之间的比例关系。前胸（颈部、头部和下颌骨）用于坑建造、猎物捕获和重新捕获以及坑清理。我们测量了 70 只幼虫的身体部位哥斯达黎加热带雨林中的Myrmeleon Brieflis。前胸表现出负异速生长：第一龄的比例大于最后一龄。这些结果支持生长假说，该假说指出食物获取是幼虫发育早期阶段的关键。第一龄期比后期龄期的食物更有限，因为它们会建造小陷阱，只有非常小的节肢动物可以落下；下颌骨较小，抓取力相对较低，增加了猎物逃跑的概率；并且脂肪储备较少，因此无法抵抗长时间的饥饿。这说明了使用比例关系更好地了解生态压力如何随着个体发育而变化的相关性，强调食物获取在早期个体发育阶段的作用