350 Biological Journal of the Linnean Society, 2018, 124, 350–362. With 6 figures. © 2018 The Linnean Society of London, Biological Journal of the Linnean Society, 2018, 124, 350–362 Morphological and ecological variation of a tropical anoline lizard: are agonistic interactions shaping ecomorphological relationships? MARCO D. BARQUERO 1,2* and FEDERICO BOLAÑOS 3 1 Sede del Caribe, Universidad de Costa Rica, Limón, Costa Rica 2 Asociación para la Conservación y el Estudio de la Biodiversidad (ACEBIO), Casa 15, Barrio Los Abogados, Zapote, San José, Costa Rica 3 Escuela de Biología, Universidad de Costa Rica, Montes de Oca, San José 2060, Costa Rica Received 5 February 2018; revised 8 April 2018; accepted for publication 8 April 2018 Ecologists have long been intrigued by which factors influence habitat use by an organism and how communities are structured. However, the links between habitat preferences, morphology, biotic interactions and community structure are still poorly understood. Moreover, interpopulation variation in ecomorphological relationships has usually been neglected. Here, we use a wide-ranging Anolis lizard, Anolis limifrons, to test whether interpopulation variation in morphology and habitat use is a function of interspecific agonistic interactions across the distribution of this species in Costa Rica. We found differences both in morphology and in habitat use among populations of A. limifrons, with populations from the Caribbean versant of Costa Rica having longer hind legs and perching lower than those from the Pacific versant. The intensity of interspecific agonistic interactions also varied across versants, with A. limifrons from Pacific sites displaying more often to congeners than those from the Caribbean. Agonistic interactions appear to be an important factor shaping habitat use and morphology. These findings can be explained by an interaction between phenotypic plasticity and ecological plasticity. ADDITIONAL KEYWORDS: Anolis limifrons – Costa Rica – ecomorphology – habitat use – mainland lizards – populations – structural habitat. INTRODUCTION One cornerstone in ecological studies has been the understanding of the relationship between morphology and ecology (Wainwright & Reilly, 1994). Extensive research has been conducted across different taxa to predict ecological attributes (e.g. habitat use and dietary breadth) based on morphological traits (da Silva et al., 2014; Villalobos & Arita, 2014; Pereira Leitão et al., 2015). These ecomorphological studies rely on the assumption that a given phenotype will perform better in an environment with specific conditions than other phenotypes, affecting fitness and the direction of selection (Losos et al., 2000). Therefore, a tight link between habitat characteristics, morphology, ecology and behaviour has been proposed (Garland & Losos, 1994), influencing the habitat selection, interspecific interactions and trophic relationships of an organism (Strong et al., 1984). Most often, this link has been analysed in comparative studies among species ( Ord & Klomp, 2014; Villalobos & Arita, 2014), although ecomorphological relationships are also present within a species (Irschick et al., 2005a, b; Chapman et al., 2015). Populations of the same species can occupy a wide range of habitats, where selective pressures could be very different (Kolbe, Larson & Losos, 2007; Lostrom et al., 2015). Therefore, high morphological variation is expected to occur among populations in traits that allow individuals to carry out relevant ecological tasks (Irschick et al., 2005a; Calderón-Espinosa, Ortega- León & Zamora-Abrego, 2013). Hence, differences in ecological attributes and behavioural responses among populations are also expected and to be predicted by phenotypic differentiation. Lizards have commonly been used to study the relationships between ecology, morphology and performance ( Schulte et al. , 2004; Irschick et al ., 2005a, b; Goodman, Miles & Schwarzkopf, 2008; *Corresponding author. E-mail: marco.barquero_a@ucr.ac.cr Downloaded from https://academic.oup.com/biolinnean/article/124/3/350/4995699 by guest on 23 March 2022