In most Papilio species, a younger larva mimics bird droppings but changes its pattern to match host plant colors in its final instar. This change is determined by juvenile hormone (JH) during the JH-sensitive period (JHSP) early in the fourth instar. Recently, we found that homeobox genes control the pre-pattern formation specifically during JHSP, but the molecular mechanisms underlying final patterning and pigmentation at molt are unknown. By knockdown of Delta and Notch in Papilio xuthus larvae, we here showed that these genes define the edge and pigmentation area in final patterns, during and even after JHSP, suggesting that they bridge the JHSP and molt. Knockdown of Delta in Papilio machaon led to similar phenotypic changes, and knockdown of Notch caused pigmentation loss in twin spots of the silkworm Multilunar (L) mutant. Our findings suggest the importance of the Notch signaling pathway in caterpillars' adaptive evolution of color pattern formation.

在大多数凤蝶物种中，幼小的幼虫模仿鸟粪，但会改变其模式以匹配最终幼虫的寄主植物颜色。这种变化是由四龄初期JH敏感期（JHSP）的幼年激素（JH）决定的。最近，我们发现同源异型框基因特别在JHSP期间控制图案前的形成，但是最终图案和蜕皮处色素沉着的分子机制尚不清楚。通过敲除三角洲和缺口在柑橘凤蝶的幼虫，我们在这里表明，这些基因中，甚至JHSP后最终图形定义边缘和色素沉着区，表明它们弥合JHSP和蜕皮。击倒的三角洲中凤蝶玛卡翁导致类似的表型变化，Notch的敲低导致家蚕多月（L）突变体的两个斑点中色素沉着的损失。我们的发现表明，Notch信号通路在毛虫适应性进化的彩色图案形成中的重要性。