Dorsal polymorphism and perch height use by Liolaemus bellii (Squamata: Liolaemidae) in central Chile

Abstract

Dorsal polymorphism is a trait broadly studied in different animal species, and polymorphism within a population is common. It is presumed that individuals with a given color pattern will have an ecological or social advantage over conspecifics without it. In several lizard species, dorsal pattern polymorphism has been related to perch use, which may be determined by a lizard’s social status. Here, we studied dorsal polymorphism and perch height use by Liolaemus bellii, a high-elevation, diurnal, saxicolous, viviparous lizard in central Chile. Discernable sexual dimorphism is absent in the species. Males and females show two morphs, a patternless one and an irregular, colored dorsal pattern characterized by olive or yellowish-brown color, flecked with yellow, black, and brown, with 8 to 10 blackish crossbars broken backward over the vertebral field (chevrons), forming an open V-like angle. We aimed to determine if lizards with this distinct chevron dorsal pattern perch higher than patternless conspecifics and if so, if conspecific social pressures might be responsible. Also, we measured eight morphological variables and evaluated their effect on perch height as covariables when lizards were grouped by sex, age class, and morph. None of the studied variables significantly influenced the presence of any morph. However, the patternless morph was found significantly more often in older lizards. Naturally broken tails increase in older lizards, although lack of a complete tail is not related to dorsal pattern. Bigger lizards with longer tails perched significantly higher, and therefore size may play a social role in perch use in L. bellii. Dorsal polymorphism in L. bellii is a conspicuous trait that has been overlooked in scientific literature concerning the species.