Alumni Research

August 5, 2014 at 2:15 pm

Lattanzio Presents Two Papers at Joint Meeting of Ichthyologists and Herpetologists

Biological Sciences alum Matthew Lattanzio ’14Ph.D.  presented two papers at the 2014 Joint Meeting of Ichthyologists and Herpetologists July 30 to Aug. 4 in Chattanooga, TN.

Lattanzio earned a Ph.D. in Biological Sciences from the College of Arts & Sciences at Ohio University in 2014.

From Disturbance to Fitness: Selective Consequences of Prescribed Fire for Tree Lizards

Abstract:Anthropogenic disturbances can have profound effects with respect to the distribution of available vegetation and structural resources. These changes in resource availability should perturb how organisms interact with each other and with their environment. Two consequences of this perturbation are increased competition for preferred resources (diet, microhabitat) and exposure to predators, potentially leading to differences in morphology and fitness among individuals in habitats differing in disturbance history. Here I ask two questions. First, does anthropogenic disturbance affect male or female survival? And second, do patterns of selection on lizard morphological traits differ by site, sex, or morph? I address these questions using three years of recapture, ecological, and morphological data from tree lizard (Urosaurus ornatus) populations at three sites differing in prescribed fire history. Tree lizards are polymorphic in dewlap coloration, and color differences among males have been linked to alternative mating strategies: blue males are territorial and aggressive, yellow males are satellite and less-aggressive, and orange males are nomadic. Preliminary data at our site suggest that male lizards in particular are larger in burned sites, and exhibit more combat-related injuries (bite-marks) than lizards in unburned areas. In contrast, aside from differences in mating behavior, little is known regarding the effects of disturbance on the ecology, morphology, or fitness of female U. ornatus lizards. My goal is to provide insight into the selective consequences of disturbance an d whether morphs differing in reproductive behavior (male and female) differ in their ability to respond to changes to their environment.

Disturbance, Microhabitat Use, and the Thermal Ecology of Male Tree Lizards

This paper was co-authored with Dr. Donald Miles, Professor of Biological Sciences at Ohio University.

Abstract: In arid environments, one of the major outcomes of anthropogenic disturbances is a shift in the thermal quality of a habitat, which should affect the ability of ectotherms (such as lizards) to exploit disturbed habitats. In this study we address these considerations for tree lizard (Urosaurus ornatus) populations at three sites differing in burn history (unburned, low-burned, and high-burned). Tree lizards are polymorphic in dewlap coloration, and color differences reflect alternative mating strategies: blue males are territorial and aggressive, yellow males are satellite and less-aggressive, and orange males are nomadic. Specifically, we aim to evaluate whether 1) historical disturbance (fire) alter the thermal quality of the habitat and 2) male lizards differing in social dominance differ in their ability to exploit higher-quality microhabitats. We combine laboratory thermal preference and critical thermal limit data with field data on lizard microhabitat use, body temperatures, and operative temperature data to address our questions. Using these data and predicted body temperatures from a statistical model, we show that disturbance may reduce environmental quality, and that lizard behavior and environmental variation may jointly affect the ability of each morph to exploit microhabitats varying in thermal quality. Specifically, less-aggressive morphs exploited poor-quality habitats, whereas more-aggressive morphs usurped live trees, which are associated with greater structural heterogeneity as well as more time that a non-regulating lizard would fall within their preferred body temperature range in the laboratory. We discuss these findings with respect to how environmental change may affect maintenance of color polymorphism in U. ornatus.

 

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