Phenotypic integration between claw and toepad traits promotes microhabitat specialization in the Anolis adaptive radiation

Abstract

The performance of an organism in its environment frequently depends more on its composite phenotype than on individual phenotypic traits. Thus, understanding environmental adaptation requires investigating patterns of covariation across functionally related traits. The replicated adaptive radiations of Greater Antillean Anolis lizards are characterized by ecological and morphological convergence, thus, providing an opportunity to examine the role of multiple phenotypes in microhabitat adaptation. Here, we examine integrated claw and toepad morphological evolution in relation to habitat partitioning across the adaptive radiations of Greater Antillean anoles. Based on analysis of 428 specimens from 57 species, we found that different aspects of claw morphology were associated with different perch dimensions, with claw height positively associated with perch diameter and claw curvature positively associated with perch height. Patterns of integration also varied across claw and toepad traits, likely driven by correlative selection for performance on smoother and rougher substrates. Finally, rates of evolution differed between claw and toepad traits, with claw length evolving faster than all other traits despite having no predicted functional importance. Our results highlight the multivariate nature of phenotypic adaptation and suggest that phenotypic integration across Greater Antillean anoles is driven by fine‐scale correlative selection based on structural habitat specialization.

Natural selection acting on integrated phenotypes: covariance among functional leaf traits increases plant fitness

“…Moreover, this issue is not exclusive for plants, as tight correlations among functional traits are also common in animals. For example: colour polymorphism is integrated with territorial behaviour in Uta stansburiana enhancing functionality of alternative reproductive strategies (Sinervo & Lively, ); toepads and claws are functionally integrated facilitating access to new niches in Anolis lizards (Yuan et al ., ); and covariance between morphological and behavioural traits represents individual differences in personality in Parus major (Moiron et al ., ). Hence, we suggest that future studies assessing the evolution of functional strategies should incorporate the multivariate relationships among traits within populations.…”

Parallel increases in grip strength in two species of Anolis lizards after a major hurricane on Dominica

“…Future studies investigating the microstructure of the setae in populations before and after Maria are needed to better understand the observed increase in clinging force. Alternatively, claw morphology was recently showed to play a role in clinging performance in anoles (Yuan, Wake & Wang, 2019). In our study, claw morphology was not quantified and could not affect clinging force because the claw was not able to penetrate the acetate surface used to record clinging force.…”

“…Alternatively, claw morphology was recently showed to play a role in clinging performance in anoles (Yuan, Wake & Wang, ). In our study, claw morphology was not quantified and could not affect clinging force because the claw was not able to penetrate the acetate surface used to record clinging force.…”

Clinging performance on natural substrates predicts habitat use in anoles and geckos

“…Species differences in toepad area, lamellae number, claw morphology, as well as actual clinging performance, have been shown to correlate with perch use, and traits can rapidly evolve in the presence of congeners (e.g. Elstrott & Irschick, 2004;Glossip & Losos, 1997;Irschick et al, 2005;Stuart et al, 2014;Yuan et al, 2019). Linkages between morphology, performance and habitat use in the field are not well studied in arboreal geckos, but there is evidence of perch height partitioning in multi-species Phelsuma communities (Harmon et al, 2007).…”