Ontogenetic color change, color choice, and evidence for male dimorphism in the polymorphic mantis Sphodromantis viridis: Insights from Mediterranean and Desert populations

Camouflage and crypsis are key survival strategies for many animals, enabling them to evade predators or enhance their ability to ambush prey. For cryptic species, effective camouflage requires not only morphological adaptations but also behavioral tactics that ensure individuals select appropriate microhabitats. However, how polymorphic cryptic species match their phenotype to their environment remains poorly understood. In this study, we investigated the morphological and behavioral plasticity of the polymorphic mantis Sphodromantis viridis from Mediterranean and desert populations to determine whether habitat selection and coloration occur when nymphs are reared in the absence of environmental color. We reared naïve individuals in color-neutral conditions and examined their morphology, development time, body length, and microhabitat preferences. Color in S. viridis is sex-linked, with males exhibiting higher proportions of brown coloration than females, and color change occurs unidirectionally from green to brown. Desert males displayed greater variance in body size and development time, forming two distinct morphs: one is smaller, greener, and matures before females, and another is larger, browner, and matures after females, suggesting alternative reproductive strategies. Neither nymphal nor adult coloration of naïve mantids influenced color choice in controlled conditions. Our findings suggest that S. viridis nymphs showed ontogenetic color change in the absence of environmental cues, which may reflect evolutionary adaptations to seasonal changes: green in spring when the vegetation is still green and brown later on when annuals dry out. Further studies on background-dependent rearing conditions could clarify how experience influences microhabitat choice.