Insect epidermal cells secrete a cuticle that serves as an exoskeleton providing mechanical rigidity to each individual, but also insulation, camouflage or communication within their environment. Cuticle deposition and hardening (sclerotization) and pigment synthesis are parallel processes requiring tyrosinase activity, which depends on an unidentified copper-dependent enzyme component in Drosophila melanogaster. We determined the metallomes of fly strains selected for lighter or darker cuticles in a laboratory evolution experiment, asking whether any specific element changed in abundance in concert with pigment deposition. The results showed a correlation between total iron content and strength of pigmentation, which was further corroborated by ferritin iron quantification. To ask if the observed increase in iron body content along with increased pigment deposition could be generalizable, we crossed yellow and ebony alleles causing light and dark pigmentation, respectively, into similar genetic backgrounds and measured their metallomes. Iron remained unaffected in the various mutants providing no support for a causative link between pigmentation and iron content. In contrast, the combined analysis of both experiments suggested instead a correlation between pigment deposition and total copper body content, possibly due to increased demand for epidermal tyrosinase activity.

昆虫表皮细胞分泌的角质层充当外骨骼，为每个个体提供机械刚性，同时也为它们的环境提供绝缘、伪装或交流。角质层沉积和硬化（硬化）和色素合成是需要酪氨酸酶活性的平行过程，这取决于黑腹果蝇中一种未知的铜依赖性酶成分. 我们在实验室进化实验中确定了为较浅或较深的角质层选择的苍蝇菌株的金属组，询问是否有任何特定元素随着色素沉积而发生大量变化。结果显示总铁含量与色素沉着强度之间存在相关性，铁蛋白铁定量进一步证实了这一点。为了询问观察到的铁体含量的增加以及色素沉积的增加是否可以推广，我们穿过黄色和乌木分别导致浅色和深色色素沉着的等位基因进入相似的遗传背景并测量它们的金属组。铁在各种突变体中保持不受影响，不支持色素沉着和铁含量之间的因果关系。相反，两项实验的综合分析表明，色素沉积与总铜体含量之间存在相关性，这可能是由于对表皮酪氨酸酶活性的需求增加。