Lizards in an Evolutionary Tree: Ecology and Adaptive Radiation of Anoles

Foreword

ix FOREWORD Lizards in an Evolutionary Tree: Ecology and Adaptive Radiation of Anoles is the tenth volume in the University of California Press’s series on organisms and environments, whose unifying themes are the diversity of plants and animals, the ways they interact with each other and with their surroundings, and the implications of those relationships for science and society. We seek books that promote unusual, even unexpected connections among seemingly disparate topics, distinguished by the talents and perspectives of their authors. Previous volumes have spanned topics as diverse as grassland ecology and bison behavior, but none has encompassed the breadth and depth of scholarly coverage achieved here. Jonathan Losos chronicles the details and historical underpinnings of an extraordinary natural legacy, the adaptive radiation of almost four hundred species of very special lizards. Thanks to their unusual diversity, abundance, and tractability, anoles have played central roles in several scientific disciplines, including physiological and community ecology, functional morphology, biogeography and molecular evolution. Losos has synthesized anole biology in lively prose, based on his own extensive studies and thousands of publications by an army of researchers over the past century. From a conceptual perspective, this book explores the cutting edges of evolutionary biology and ecology, our search for patterns and causal explanations for biodiversity. Why are there more species in some places than others, and what drives diversification? How do individuals interact with others of their species? Is competition among species important? And what will be the fate of anoles on our rapidly changing planet? losos_fm.qxd 4/11/09 9:52 AM Page ix Lizards in an Evolutionary Tree also explores these fascinating, often beautiful reptiles for their own sake. Only one species is widespread in the southeastern United States, but some tropical sites perhaps boast fifteen species and Cuba has sixty-three. Anoles typically have large heads and limbs, long slender tails, small granular scales, and feet specialized for gripping. Their color patterns are generally cryptic and a few can change hues dramatically within seconds. The males of most species and the females of some have a distensible, often brightly colored dewlap used in social signaling. Any suspicion that “you’ve seen one, seen them all” is squashed by rare Amazonian anoles with leaflike proboscises and by a kaleidoscopically orange-splotched Andean species with large flat scales among its granules. Certain Cuban anoles with their large eyes, prehensile tails, and slow-motion lifestyles are reminiscent of Old World chameleons. Anoles are ecologically diverse as well. A few species are as big as a good-sized rodent and scamper among the trunks and canopy foliage of rainforest trees; some no larger than a ballpoint pen creep along twigs, while a few still smaller ones live on fallen branches and in leaf litter. Several species are semiaquatic and another hangs around cave entrances. Most anoles feed on arthropods, but at least one takes snails, and larger species sometimes add fruit and vertebrates to their diets. On the other side of the predator-prey coin, anoles are often common and they must be tasty, because spiders, frogs, other lizards, snakes, birds, and mammals eat them. Despite all this diversity, local assemblages are often predictably structured. Visit Caribbean islands, pay attention to anoles, and each place you will see so-called “crown giant,” “trunk,” “twig,” and “grass” species, with independently evolved similarities to those same “ecomorphs” elsewhere. A third theme lurks herein, beyond concepts and organisms, of academic lineages. Who does all this work and why would anyone devote decades to studying an adaptive radiation? Harvard’s late professor Ernest Williams initiated anole work and by the end of the 1970s had supervised a string of unusually creative doctoral students working on these lizards. Meanwhile ten-year-old Jonathan, already well known to curators at his hometown zoo as an “animal nerd,” had been mesmerized by anoles on a family trip to Florida. He later devoted two secondary school science projects to them, completed an undergraduate thesis on their social behavior with Williams, and his Berkeley Ph.D. was going to be on something else! My new student tried monitors, geckos, and chameleons, then succumbed to destiny. It’s been anoles for more than thirty years now, and although he’s briefly escaped to other lizards and even opossums, a steady stream of exciting new mysteries keeps reeling him back to those childhood favorites. And what of the future? Anoles now stand among the most diverse and thoroughly studied of all adaptive radiations, rivaling...