Publications (4)19.23 Total impact
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Article: Ecological and Evolutionary Processes Drive the Origin and Maintenance of Imperfect Mimicry.
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ABSTRACT: Although the forces behind the evolution of imperfect mimicry remain poorly studied, recent hypotheses suggest that relaxed selection on small-bodied individuals leads to imperfect mimicry. While evolutionary history undoubtedly affects the development of imperfect mimicry, ecological community context has largely been ignored and may be an important driver of imperfect mimicry. Here we investigate how evolutionary and ecological contexts might influence mimetic fidelity in Müllerian and Batesian mimicry systems. In Batesian hoverfly systems we find that body size is not a strong predictor of mimetic fidelity. However, in Müllerian velvet ants we find a weak positive relationship between body size and mimetic fidelity when evolutionary context is controlled for and a much stronger relationship between community diversity and mimetic fidelity. These results suggest that reduced selection on small-bodied individuals may not be a major driver of the evolution of imperfect mimicry and that other factors, such as ecological community context, should be considered when studying the evolution of imperfect mimicry.PLoS ONE 01/2013; 8(4):e61610. · 4.09 Impact Factor -
Article: Drivers of hybridization in a 66-generation record of Colias butterflies.
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ABSTRACT: Hybridization significantly affects the ecology and evolution of numerous plant and animal lineages. Most studies have focused on endogenous drivers of hybridization and neglected variation in exogenous factors, such as seasonal weather patterns. In this study, we take advantage of a unique dataset consisting of records of hybridization between the butterflies Colias eurytheme and C. eriphyle (Pieridae) for 66 generations (22 years) to investigate the importance of seasonal weather on the production and survival of hybrid offspring. Important seasonal weather variables for each parental species and hybrid offspring were determined using model averaging, and these weather variables, along with butterfly abundances, were analyzed using path analysis. The most important drivers of hybridization were the abundance of C. eriphyle, summer minimum temperature, and spring maximum temperature. In contrast, the abundance of C. eurytheme and weather variables prior to the current flight season were relatively unimportant for variation in hybrid abundance. Parental abundances were mostly driven by weather variables prior to the flight season possibly because these variables affect host plant quality. Our results suggest that exogenous, climatic factors can influence hybridization in natural systems, and that these factors can act both directly on hybrid abundance and indirectly through the population dynamics of parental species.Evolution 03/2012; 66(3):818-30. · 5.15 Impact Factor -
Article: The race is not to the swift: long-term data reveal pervasive declines in California's low-elevation butterfly fauna.
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ABSTRACT: Understanding the ecology of extinction is one of the primary challenges facing ecologists in the 21st century. Much of our current understanding of extinction, particularly for invertebrates, comes from studies with large geographic coverage but less temporal resolution, such as comparisons between historical collection records and contemporary surveys for geographic regions or political entities. We present a complementary approach involving a data set that is geographically restricted but temporally intensive: we focus on three sites in the Central Valley of California, and utilize 35 years of biweekly (every two weeks) surveys at our most long-sampled site. Previous analyses of these data revealed declines in richness over recent decades. Here, we take a more detailed approach to investigate the mode of decline for this fauna. We ask if all species are in decline, or only a subset. We also investigate traits commonly found to be predictors of extinction risk in other studies, such as body size, diet breadth, habitat association, and geographic range. We find that population declines are ubiquitous: the majority of species at our three focal sites (but not at a nearby site at higher elevation) are characterized by reductions in the fraction of days that they are observed per year. These declines are not readily predicted by ecological traits, with the possible exception of ruderal/non-ruderal status. Ruderal species, in slightly less precipitous decline than non-ruderal taxa, are more dispersive and more likely to be associated with disturbed habitats and exotic hosts. We conclude that population declines and extirpation, particularly in regions severely and recently impacted by anthropogenic alteration, might not be as predictable as has been suggested by other studies on the ecology of extinction.Ecology 12/2011; 92(12):2222-35. · 4.85 Impact Factor -
Article: Use of exotic hosts by Lepidoptera: widespread species colonize more novel hosts.
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ABSTRACT: The study of host shifts by herbivorous insects has played an important role in evolutionary biology, contributing to research in coevolution, ecological speciation, and adaptive radiation. As invasive plants become more abundant in many ecosystems, the potential for exotic host use by native insects increases. Graves and Shapiro (2003) have documented exotic host use by 34% of Californian butterflies, suggesting that the plants and butterflies of California might be an important model system for the colonization and utilization of novel resources. In this study, we analyze relationships among geographic range, native diet breadth, and the use of exotic hosts by Californian butterflies and skippers (Lepidoptera). Geographic range and, to a lesser extent, native diet breadth are significant predictors of exotic host use, with positive relationships found both before and after phylogenetic correction. These results give insight into the process of insect host range evolution, as geographically widespread generalists have an apparently greater tendency to use novel, exotic hosts than geographically constrained specialists. Increasing occurrences of exotic host use are expected and those species not capable of shifting to nonnative hosts are likely to have higher vulnerability to extirpation and extinction in the future.Evolution 09/2011; 65(9):2719-24. · 5.15 Impact Factor
Top co-authors
Institutions
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2012
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University of Nevada, Reno
- Department of Biology
Reno, NV, USA
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