Mating opportunities and energetic constraints drive variation in age-dependent sexual signalling

When males repeatedly produce energetically expensive sexual signals, trade-offs between current and future investment can cause plasticity in age-dependent signalling. Such variation is often interpreted as alternate adaptive strategies: live fast and die young vs. slow and steady. An alternative (yet rarely tested) explanation is that condition-dependent constraints on allocation cause variation in signalling with age (‘late bloomers’ do not have early investment options). Testing this hypothesis is challenging because resource acquisition and allocation are difficult to measure, and energetic reserves both affect and are affected by reproductive effort. We simultaneously manipulated acquisition (through dietary nutrition) and access to potential mates (as a proxy for manipulating sexual trait allocation) in male decorated crickets (Gryllodes sigillatus), while measuring age- and signalling effort-mediated changes in energy storage components. Increased diet quality caused increase...当雄性反复产生能量成本高昂的性信号（sexual signals）时，当前与未来繁殖投入之间的权衡会引发年龄依赖信号表达的可塑性。这种变异通常被解读为两种交替的适应性策略：即“快活早逝”与“慢稳存续”。 另一种（但极少得到验证）解释是，资源分配的条件依赖约束会导致信号表达随年龄产生变异——“大器晚成者”并无早期投入的选项。验证这一假说颇具挑战，因为资源获取与分配难以测量，且能量储备既会影响繁殖投入，同时也受繁殖投入的调控。 我们在装饰蟋蟀（Gryllodes sigillatus）雄性个体中，同时操控了其资源获取途径（通过膳食营养）与潜在配偶可获得性（作为操控性特征分配的替代指标），同时测量了年龄与信号投入介导的能量储存组分变化。 膳食营养质量的提升会导致……