Phenotypic Variation and the Behavioral Ecology of Lizards

Abstract

Behavioral ecology is the study of how animal behavior evolves in the context of ecology, thus melding, by definition, investigations of how social, ecological, and evolutionary forces shape phenotypic variation within and across species. Framed thus, it is apparent that behavioral ecology also aims to cut across temporal scales and levels of biological organization, seeking to explain the long-term evolutionary trajectory of populations and species by understanding short-term interactions at the within-population level. In this dissertation, I make the case that paying attention to individuals’ natural history—where and how individual organisms live and whom and what they interact with, in natural conditions—can open avenues into studying the behavioral ecology of previously understudied organisms, and more importantly, recast our understanding of taxa we think we know well. In Chapters 1 and 2, I investigate the consequences of paying attention to individuals’ movement patterns for understanding the mating system of Anolis lizards (Dactyloidae). Chapter 1 is a historical review of Anolis social and reproductive behavior, in which I show that because individual variation in movement and social behavior was consistently ignored or downplayed in studies of Anolis mating systems, the conclusion that anoles are territorial and polygynous remains poorly supported by behavioral evidence. In Chapter 2, I examine movement behavior in a population of Anolis sagrei, and show that individuals’ movement behavior allows females to encounter and potentially mate with multiple males, which is counter to previous behavioral descriptions of Anolis mating systems but is consistent with growing genetic evidence for female multiple mating. The potential implications for sexual selection are discussed. In Chapter 3, I show that individual A. sagrei are specialized in habitat use, and that the degree of specialization among individuals in the sampled population in Gainesville, FL, is comparable to the degree of specialization across habitat specialist species in a community of Greater Antillean anoles. However, individual specialization in habitat use is not related to available habitat or to the morphological traits that explain habitat use specialization across species and populations of habitat use, suggesting that macroevolutionary patterns in this group are not simply microevolutionary patterns “writ large.” Finally, in Chapter 4, I quantify variation in display behavior, morphology, and habitat in the fan-throated lizard (Sitana and Sarada; Agamidae) species complex, and find that display behavior is partially but not completely associated with ornament elaboration in this group. Moreover, though habitat structure does not play a role in the maintenance of throat-fan and display variation, sexual selection very likely shaped the dramatic variation in ornament morphology in this group.