Ryan G. Calsbeek - US grants

One of the key ways that biological diversity arises is through variation in success at obtaining mates. Females often control access to mating and choose only to mate with males that display elaborate traits. Sexual selection remains a controversial topic, due in part to the difficulty of understanding how mate choice varies across environments. This proposal explores ecological factors that drive adaptive mate choice in Caribbean Anolis lizards, a group noted for its great variation in body size. Laboratory and field experiments on one species will contrast the roles of natural selection and sexual selection in shaping both mate choice and male body size, a trait that has different effects on the success of males and females.

The study is designed to advance science training of middle and high school students, graduate students, and a post-doctoral researcher, in both the field and laboratory. Students from under-represented groups will be recruited. During the year, high-school students will apply what they learn in their research and coursework to teach middle-school students in the Bahamas about their local environments. Island School students will present data at a local community outreach fair and participate in a research symposium attended by government officials, scientists, conservation groups, and locals. Grant personnel will serve as mentors to six Island School students per semester and supervise studies that feed into the research goals of this proposal.

Human life is hard work: getting an education, working, raising children, paying the mortgage, etc. But how hard do free-living animals work during their routine day-to-day activities, such as when breeding, escaping predators, finding food, or choosing a mate? What determines how hard individuals will work on specific activities? Can the term "exercise", perhaps defined as activity for the sake of improving or maintaining performance be applied to these routine behaviors? Is there evidence that free-living animals "train" to improve performance prior to onset of high levels of activity? Can animals work too hard, such that they pay costs of high levels of activity? Until recently, much work on animal movement has been based in the laboratory and has been divorced from ecological context. However, there have been rapid, recent advances in animal tracking technology which are giving biologists an unprecedented ability to track continuously the behavior of individual free-living animals. This will allow researchers to directly address the questions posed above, advancing our understanding of just how hard free-living animals work and why some individuals might work harder than others.

By combining the power of recent technological advances in animal tracking or "bio-logging" (automated radio-tracking arrays, geolocators, GPS, accelerometers), with complex, multivariate behavioral and physiological analysis biologists can address three key themes: a) individual variation in the intensity of movement, behavior or performance in response to challenging ecological scenarios; b) physiological mechanisms underlying this individual variation, and c) fitness consequences of individual variation in work-load of free-living animals. This full-day symposium on The Ecology of Exercise will bring together speakers covering a wide range of animal taxa, and different types of activity, behavior or performance. The topics will address multiple levels of organization, such as immunological response, ontogenetic stages, and kinesiology aspects of performance. The breadth of this symposium is expected to attract a broad audience and a substantial number of submissions for the associated paper and poster presentation sessions, particularly from students who are training in related areas of science. A special issue of Integrative and Comparative Biology will be produced featuring papers from the symposium talks.

All living things change and grow through time. Some of these changes are more dramatic than others. The changes that amphibians (e.g., frogs and salamanders) undergo during development are some of the most dramatic of any of the vertebrates. Metamorphosis is the process by which an amphibian transforms from an animal that lives under water, to one that lives on land. This incredible transition involves reorganizing almost the entire animal's body plan. Many species of amphibians absorb their tails, grow legs for moving on land, and their external gills disappear as they begin breathing air. All of these amazing changes are controlled by a single set of genes. This project will explore the various ways that natural selection has sculpted the amphibian genome to build these two vastly different types of animal bodies with the same sets of genes. Using the wood frog (Rana sylvatica) as a study system, the researchers will explore the role of different environmental factors that can influence the development of both tadpoles and adult frogs. In doing so, the research will determine how the environment interacts with gene expression to influence survival and mating success of wood frogs. Metamorphosis is a fascinating process to watch and provides opportunities for study at multiple age levels. The researchers will involve elementary school students, high school students, and both graduate and undergraduate researchers in the studies. Ultimately, this project will make important contributions to understanding how natural selection influences genes and genomes to make animals that are well suited to multiple environments.

A central problem in the study of life history evolution is to understand how tradeoffs play a role in structuring natural populations. This project investigates potential tradeoffs between traits expressed during alternative life stages (i.e., tadpoles versus adults) in wood frogs, Rana sylvatica. For example, tradeoffs may arise across the life history of anurans because their complex life history requires dramatically different forms of adaptation to match changes in ecology, morphology, and behavior following metamorphosis. However, such tradeoffs could be alleviated if genetic correlations are broken apart during metamorphosis (so called "adaptive-decoupling"), or if traits are subject to similar forms of natural selection throughout the life history. Although the idea of adaptive-decoupling is not new, we still understand surprisingly little about the degree to which anuran life-stages are coupled and how this might influence adaptation in each life stage. This project will test for differences in the forms of natural selection between tadpoles and frogs using a combination of semi-natural mesocosms (tadpoles) and field enclosures (frogs). The degree of adaptive-decoupling will be measured using a half-sib breeding design to quantify genetic correlations within and between life-stages. Field surveys of natural populations that vary in predation intensity and timing (e.g., predation at larval and/or adult life stages) will test the prediction that natural selection and adaptive-decoupling interact to influence local adaptation. Further, the researchers will test whether shifts in gene expression and natural selection interact to influence traits important for mating success.

An award is made to Dartmouth College to acquire an acoustic camera for tracking sources of sound in video. The acoustic camera will contribute to multidisciplinary research, teaching and outreach. A teaching module will be developed on the acoustics of natural landscapes using the acoustic camera that can be customized and incorporated into graduate courses, undergraduate courses and teacher training for professional development days. Dartmouth's Science & Technology Outreach team will assist with delivering products from the acoustic camera to the broader community, such as interactive audiovisual depictions of songbird choruses for the Hubbard Brook LTER web portal, movies from research on the acoustics of bats, frogs and primates to present at a local science pub, and audiovisual displays for the website of a National Public Radio special series on sounds in nature.

Sound recordings provide rich information about natural systems and human environments. A major limitation of acoustic recordings, however, is that they do not provide information about the direction or location of the sound source. An acoustic camera is a cutting-edge instrument that integrates both visual and acoustic information to generate video images that identify the direction and source of sounds using a video camera, microphone array, data acquisition board and processing computer. At Dartmouth, there is an unusually large and interdisciplinary community of people united by an interest in acoustics and natural sounds. The acquisition of an acoustic camera will elevate the individual research and teaching programs of multiple faculty in multiple disciplines who study the transmission and identity of sounds in the environment. Furthermore, the acoustic camera will foster cross-disciplinary collaborations among faculty in Biology, Anthropology, Music, and other disciplines. Current projects across the university address the role of sounds in evolutionary processes. These projects range from the dynamics and evolutionary drivers of social interactions in acoustically signaling animals, to the role of soundscapes in the evolution of human hearing, language and music. The ability to assign sounds to individuals within aggregations or pairwise interactions in field conditions will enable researchers to answer unresolved questions for a variety of projects across disciplines.