Leila Siciliano-Martina (EEB student, Light and Lawing Labs) will be defending her dissertation proposal Monday, May 13 at 12:00 pm in WFES 336 and everyone is invited to attend the public portion of the proposal defense.
Her talk title is Unintended Morphological Impacts of Captivity
Summary: The morphological differences that exist between captive and wild populations have been a recurrent theme in scientific literature for at least a century; however, the exact trends, mechanisms, and consequences of these differences are poorly understood. My dissertation research will address some of the long-standing questions and hypotheses associated with captive morphology by conducting meta-analyses on previously published data and using geometric morphometric techniques on newly acquired cranial and mandibular photographs of captive, wild, and reintroduced canids. Although the morphology of captive populations seems to shift in predictable ways, these trends have yet to be examined using a thorough, quantitative approach. By conducting a meta-analysis, this research will address whether captive animals show predictably distinct morphology and whether those changes are impacted by lifestyle covariates shared across species. Preliminary results suggest that cranial measures differ significantly between captive and wild populations of several mammalian orders, although the magnitude and direction of the changes appears to vary with taxonomy and diet. Similarly, by examining the nature, magnitude, and directionality of morphological shifts that occur over captive generations among different canid species, my research will further illuminate the ways in which captive populations change, the key predictors of these morphological shifts, the number of captive generations required for changes to become apparent, and any driving mechanisms. For example, previous studies have shown that the morphology of captive carnivorans differs in cranial regions strongly associated with bite force, which could have significant implications for the success of captively-bred reintroduced animals. Initial results regarding the Mexican wolf (Canis lupus baileyi) suggest that the cranial morphology of historic wild populations differs significantly from both captive and reintroduced populations in cranial regions associated with bite force. To further examine the functional differentiation of captive populations, my research will also estimate bite force and evaluate dietary differences between wild and reintroduced populations. Understanding how species change in captivity can help predict the challenges facing reintroduction efforts and the ways captive management should be altered to help mitigate those effects. By documenting the differentiation of wild and captive animals, the findings of this study will provide commentary on the controversies associated with captive reintroductions and test a number of the long-standing hypotheses associated with the morphological differentiation of captive populations.
Mickey Parker (EEB student, Fitzgerald Lab) will be defending his dissertation proposal this Friday at 9 am in WFES 236 and everyone is invited to attend the public portion of the proposal defense.
Title: Improving Translocation Outcomes for Habitat Specialist Species: Population Restoration of Sceloporus arenicolus in West Texas.
Use of conservation translocations to combat biodiversity loss has been steadily increasing since the 1960s, and this is projected to continue, especially in highly populated and biodiverse countries. While much of the narrative surrounding the current biodiversity crisis is focused on extinctions, population declines and range reductions are important sources of biodiversity loss and present opportunities to restore populations using conservation translocations. Research that can contribute to improving the outcomes of conservation translocations is critical for reversing biodiversity loss in the Anthropocene. My dissertation will build upon ongoing research centered on a conservation translocation of an extreme habitat specialist, the dunes sagebrush lizard (Sceloporus arenicolus), in West Texas. The aim of research is to improve success rates of reintroductions and other types of conservation translocations by examining the effects of interspecific interactions (particularly those between specialist and generalist species), habitat fragmentation, and life history on translocation outcomes, using the lizard communities of the Mescalero-Monahans Sandhills as a study system.
EEB affiliate student (WFSC) Luke Bower’s dissertation defense is scheduled for 1 p.m. on Friday, April 19 in WFES 119.
Luke’s talk title is “Convergence and community assembly of stream fishes: an intercontinental analysis.”
Stephen Bovio (EEB student, Rosenthal Lab) will be defending his dissertation proposal this Thursday, April 11 and everyone is invited to attend the public portion of the proposal defense (info below). His public presentation will be at 2 pm in WFES 411.
His talk title is Evolutionary consequences of natural and sexual selection on hybridizing swordtails
Summary: Hybridization is a common phenomenon that serves as an important evolutionary mechanism by which diversity can arise. When two genetically divergent species hybridize, the resulting admixture generates novel genotypic and phenotypic combinations that selection can act upon. In the Rosenthal lab, we study two freshwater species of fish, Xiphophorus birchmanni and X. malinche, that form natural replicated hybrid zones in the Sierra Madre Oriental in Hdg, MX. The birchmanni-malinche system offers a unique opportunity to study long-standing evolutionary questions regarding the consequences of ecological and sexual selection on hybrid populations due to their unique natural history and ecological circumstances. Xiphophorus malinche are found at high elevations while X. birchmanni are found at lower elevations – at intermediate elevations, hybrids form. The core of my dissertation will focus on the collection and analysis of data generated from our long-term research project aimed at monitoring hybrid evolution for ten generations. Replicated mesocosms at high, intermediate, and low elevations initially seeded with F1 hybrids will enable me to characterize changes in phenotypes and genotypes for early generation hybrids. Specifically, I will investigate how thermal selection and pre- and postmating sexual selection act on early generation hybrid populations.