The double cloak of invisibility: phenotypic plasticity and larval decoration in a geometrid moth,Synchlora frondaria, across three diet treatments

Abstract

Abstract1. Crypsis is one of the main defences that insects use to avoid predators, and both the juveniles and adults of many geometrid moths are remarkable in their ability to blend into different host backgrounds. The larvae ofSynchlora frondariahave two methods to achieve crypsis: phenotypic plasticity in colouration that enable them to hide more effectively on their host plants, and a self‐decorating behaviour whereby the larvae camouflage themselves with materials from their host plants.2. Larvae ofSynchlora frondariareared on three different host plants showed systematic differences in relative growth rate, survivorship and larval colouration.3. Larval colouration varied across diet treatments in a way that was consistent with diet‐induced phenotypic plasticity, and larvae also exhibited characteristic decorating behaviour on all three hosts.4. Larvae showed highest survivorship onHeterotheca subaxillaris(Asteraceae), and had significantly higher relative growth rates onH. subaxillaris(Asteraceae) andLantana camara(Verbenaceae) than onBejaria racemosa(Ericaceae).5. Synchlora frondariaprovides an example of a species where both decorating behaviour and phenotypic plasticity in larval colouration produce a cryptic form that is remarkably responsive to its background.