Data from: Anticipatory flexibility: larval population density in moths determines male investment in antennae, wings and testes

Developmental plasticity provides individuals with a distinct advantage when the reproductive environment changes dramatically. Variation in population density, in particular, can have profound effects on male reproductive success. Females may be easier to locate in dense populations, but there may be a greater risk of sperm competition. Thus, males should invest in traits that enhance fertilization success over traits that enhance mate location. Conversely, males in less dense populations should invest more in structures that will facilitate mate location. In Lepidoptera, this may result in the development of larger antennae to increase the likelihood of detecting female sex pheromones, and larger wings to fly more efficiently. We explored the effects of larval density on adult morphology in the gum-leaf skeletoniser moth, Uraba lugens, by manipulating both the number of larvae and the size of the rearing container. This experimental arrangement allowed us to reveal the cues used by larvae to assess whether absolute number or density influences adult responses. Male investment in testes size depended on the number of individuals, while male investment in wings and antennae depended upon larval density. In contrast, the size of female antennae and wings were influenced by an interaction of larval number and container size. This study demonstrates that male larvae are sensitive to cues that may reveal adult population density, and adjust investment in traits associated with fertilization success and mate detection accordingly.

发育可塑性（Developmental plasticity）可使个体在繁殖环境发生剧烈变化时获得显著优势。种群密度的波动，尤其会对雄性繁殖成功率产生深远影响。高密度种群中，雌性个体更易被定位，但雄性面临的精子竞争风险也更高。因此，雄性应将资源投入到提升受精成功率的性状，而非配偶定位相关性状。反之，低密度种群中的雄性则应更多投资于辅助配偶定位的结构。在鳞翅目（Lepidoptera）昆虫中，这一策略可能表现为发育出更大的触角以提升检测雌性性信息素的概率，以及更大的翅膀以提升飞行效率。本研究以桉叶骨架蛾（Uraba lugens）为研究对象，通过调控幼虫数量与饲养容器尺寸，探究了幼虫密度对成虫形态的影响。该实验设计可帮助我们明确幼虫用以判断种群绝对数量或密度的线索。研究结果显示，雄性精巢大小仅受幼虫个体数量影响，而雄性翅膀与触角的投资则取决于幼虫密度。与之相反，雌性触角与翅膀的大小同时受幼虫数量与容器尺寸的交互作用影响。本研究证实，雄性幼虫可通过感知相关线索推断成虫种群密度，并据此调整与受精成功率及配偶识别相关的性状投资策略。