Theory predicts that warning signals should exhibit low variation to increase learning efficiency in predators. Many species, however, exhibit variation in warning colours within species and even within populations. An understudied example of within species variation is that between life stages, where animals change warning colouration throughout ontogeny. Understanding how warning signals change throughout life can help us identify the different ecological pressures that affect the evolution of warning signals. We used the Australasian cotton harlequin bug (Tectocoris diophthalmus) to explore how adults and nymphs differ in their defensive secretions and colouration. We performed spectrophotometric colour measurements and toxicity bioassays. Our results show, overall, no consistent association between colour and toxicity within species. There was no clear pattern for females and nymphs. Adult males, however, present the highest contrast against backgrounds, highest internal contrast, and highest toxicity. There was no association between colour and toxicity within males, nymphs or females. Our results suggest weak signal honesty in warning signals across life stages and sexes, and demonstrate that variation in colour within species is not necessarily linked to changes in toxicity.

中文翻译：

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在 aposematic bug 的整个生命阶段的警告信号中没有诚实

理论预测警告信号应该表现出低变化以提高捕食者的学习效率。然而，许多物种在物种内甚至种群内表现出警告颜色的变化。物种内变异的一个未充分研究的例子是生命阶段之间的变异，动物在整个个体发育过程中都会改变警告颜色。了解警告信号在整个生命过程中如何变化可以帮助我们识别影响警告信号演变的不同生态压力。我们使用澳大利亚棉花小丑虫 (Tectocoris diophthalmus) 来探索成虫和若虫在防御性分泌物和颜色方面的差异。我们进行了分光光度颜色测量和毒性生物测定。我们的结果显示，总体而言，物种内的颜色和毒性之间没有一致的关联。雌性和若虫没有明确的模式。然而，成年男性与背景的对比度最高，内部对比度最高，毒性最高。雄性、若虫或雌性的颜色和毒性之间没有关联。我们的结果表明，跨生命阶段和性别的警告信号的信号诚实性较弱，并表明物种内颜色的变化不一定与毒性变化有关。