Influência da dieta na evolução de Iguania em ambientes florestais

Abstract

Stemming from the recent phylogenetic reorganization that positions Iguania as a derived clade within Squamata, this study investigated the hypothesis that the secondary loss of the vomeronasal organ (VNO) may have favored an adaptation to low-lipid diets, thereby facilitating the colonization of forest environments. Through a macroevolutionary meta-analysis of the diets of 62 species, and using Phylogenetic Generalized Least Squares (PGLS) models with prey biomass data standardized by custom regression models, the influence of ecological factors and evolutionary history on dietary lipid content was evaluated. The results refuted the central premise: no significant differences were found in lipid content between lizards from open and forest habitats, nor as a function of foraging mode or thermoregulation. The analysis revealed that lipid content is an evolutionarily labile trait with a nearly null phylogenetic signal, being significantly lower only in species from mixed habitats (ecotones). These findings indicate that dietary lipid composition is shaped by local ecological pressures and does not represent a conserved adaptive syndrome for forest life. More broadly, the results open space for an alternative interpretation: the transition to visually oriented hunting may have acted as an ecological release, enabling Iguania to exploit chemically defended prey and turning an apparent sensory “loss” into an expansion of ecological opportunities.