ORCID Profile
0000-0002-3359-1631
Current Organisation
University of Kansas
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Publisher: Museums Victoria
Date: 2018
Publisher: Wiley
Date: 10-10-2012
DOI: 10.1111/J.1558-5646.2012.01795.X
Abstract: Although the importance of signals involved in species recognition and sexual selection to speciation is widely recognized, the processes that underlie signal ergence are still a matter of debate. Several possible processes have been hypothesized, including genetic drift, arbitrary sexual selection, and adaptation to local signaling environments. We use comparative analyses to investigate whether the remarkable geographic variation of dewlap phenotype in a Hispaniolan trunk Anolis lizard (A. distichus) is a result of adaptive signal ergence to heterogeneous environments. We recover a repeated pattern of ergence in A. distichus dewlap color, pattern, and size with environmental variation across Hispaniola. These results are aligned with ecological models of signal ergence and provide strong evidence for dewlap adaptation to local signaling environments. We also find that A. distichus dewlaps vary with the environment in a different manner to other previously studied anoles, thus expanding upon previous predictions on the direction dewlaps will erge in perceptual color space in response to the environment.
Publisher: Wiley
Date: 27-09-2011
Publisher: Elsevier BV
Date: 02-2011
Publisher: Wiley
Date: 25-11-2010
DOI: 10.1111/J.1558-5646.2010.01177.X
Abstract: Barriers to dispersal and resulting biogeographic boundaries are responsible for much of life's ersity. Distinguishing the contribution of ecological, historical, and stochastic processes to the origin and maintenance of biogeographic boundaries, however, is a longstanding challenge. Taking advantage of newly available data and methods--including environmental niche models and associated comparative metrics--we develop a framework to test two possible ecological explanations for biogeographic boundaries: (1) sharp environmental gradients and (2) ribbons of unsuitable habitat iding two highly suitable regions. We test each of these hypotheses against the null expectation that environmental variation across a given boundary is no greater than expected by chance. We apply this framework to a pair of Hispaniolan Anolis lizards (A. chlorocyanus and A. coelestinus) distributed on the either side of this island's most important biogeographic boundary. Integrating our results with historical biogeographic analysis, we find that a ribbon of particularly unsuitable habitat is acting to maintain a boundary between species that initially erged on distinct paleo-islands, which merged to form present-day Hispaniola in the Miocene.
Publisher: Springer Science and Business Media LLC
Date: 26-06-2009
Publisher: Public Library of Science (PLoS)
Date: 10-04-2013
Publisher: Oxford University Press (OUP)
Date: 2013
Abstract: The ersity of sexual signals is astounding, and ergence in these traits is believed to be associated with the early stages of speciation. An increasing number of studies also suggest a role for natural selection in driving signal ergence for effective transmission in heterogeneous environments. Both speciation and adaptive ergence, however, are contingent on the sexual signal being heritable, yet this often remains assumed and untested. It is particularly critical that the heritability of carotenoid-based sexual signals is investigated because such traits may instead be phenotypically plastic indicators of an in idual's quality that exhibit no or little heritable variation. We present the first study to investigate the relative contribution of genetic and environmental factors to the striking ersity of dewlap color and pattern in Anolis lizards. Using a breeding experiment with Anolis distichus populations exhibiting different dewlap phenotypes, we raise F1 offspring in a common garden experiment to assess whether dewlap color is inherited. We follow this with carotenoid supplementation to investigate the influence of dietary pigments to dewlap color variation. We find significant differences in several aspects of dewlap color and pattern to persist to the F1 generation (fathers: N = 19 F1 males: N = 50 P 0.05). These results strongly support that genetic differences underlie dewlap color variation, thereby satisfying a key requirement of natural selection. Our findings provide an important stepping-stone to understanding the evolution of an incredibly erse signal important for sexual selection and species recognition.
Publisher: Wiley
Date: 02-2010
Publisher: Wiley
Date: 19-01-2021
DOI: 10.1111/ECOG.05485
Abstract: The ENMTools software package was introduced in 2008 as a platform for making measurements on environmental niche models (ENMs, frequently referred to as species distribution models or SDMs), and for using those measurements in the context of newly developed Monte Carlo tests to evaluate hypotheses regarding niche evolution. Additional functionality was later added for model selection and simulation from ENMs, and the software package has been quite widely used. ENMTools was initially implemented as a Perl script, which was also compiled into an executable file for various platforms. However, the package had a number of significant limitations it was only designed to fit models using Maxent, it relied on a specific Perl distribution to function, and its internal structure made it difficult to maintain and expand. Subsequently, the R programming language became the platform of choice for most ENM studies, making ENMTools less usable for many practitioners. Here we introduce a new R version of ENMTools that implements much of the functionality of its predecessor as well as numerous additions that simplify the construction, comparison and evaluation of niche models. These additions include new metrics for model fit, methods of measuring ENM overlap, and methods for testing evolutionary hypotheses. The new version of ENMTools is also designed to work within the expanding universe of R tools for ecological biogeography, and as such includes greatly simplified interfaces for analyses from several other R packages.
Publisher: Wiley
Date: 11-2008
DOI: 10.1111/J.1558-5646.2008.00482.X
Abstract: Environmental niche models, which are generated by combining species occurrence data with environmental GIS data layers, are increasingly used to answer fundamental questions about niche evolution, speciation, and the accumulation of ecological ersity within clades. The question of whether environmental niches are conserved over evolutionary time scales has attracted considerable attention, but often produced conflicting conclusions. This conflict, however, may result from differences in how niche similarity is measured and the specific null hypothesis being tested. We develop new methods for quantifying niche overlap that rely on a traditional ecological measure and a metric from mathematical statistics. We reexamine a classic study of niche conservatism between sister species in several groups of Mexican animals, and, for the first time, address alternative definitions of "niche conservatism" within a single framework using consistent methods. As expected, we find that environmental niches of sister species are more similar than expected under three distinct null hypotheses, but that they are rarely identical. We demonstrate how our measures can be used in phylogenetic comparative analyses by reexamining niche ergence in an adaptive radiation of Cuban anoles. Our results show that environmental niche overlap is closely tied to geographic overlap, but not to phylogenetic distances, suggesting that niche conservatism has not constrained local communities in this group to consist of closely related species. We suggest various randomization tests that may prove useful in other areas of ecology and evolutionary biology.
No related grants have been discovered for Richard Glor.