Camouflage variations on a theme of the nymphalid ground plan

Abstract

Lepidopteran camouflage patterns offer sophisticated and captivatedexamples of morphological evolution. Previous studies focused on how and whycamouflage patterns are modulated at the microevolutionary level and determined,for instance, the adaptive role of camouflage patterns in avoiding predator attacks.However, less attention has been paid to the macroevolution of camouflage,including the evolutionary paths leading to the origination of leaf mimicry patterns.To understand the deep origins and evolvability of camouflage patterns, a keyprinciple comes from a highly conserved ground plan (termed the nymphalidground plan; NGP). The ground plan generates a variety of morphological forms,while it maintains its own type. This review introduces several seminal studies thatused NGP-known features to reveal the macroevolutionary aspects of lepidopterancamouflage patterns, providing a roadmap for further understanding this biologicalphenomenon. The following core themes are discussed: (1) how complex camouflagepatterns evolved (macroevolutionary pathways), (2) what kind of flexiblemechanisms facilitate the origin of such complex patterns (macro-evolvability),and (3) how such complex patterns are tightly integrated through the coupling anduncoupling of ancestral developmental mechanisms (body plan character map).These approaches will provide new research lines for studying the evolution ofcamouflage patterns and the underlying flexibility of the NGP.