NSF Postdoctoral Fellowship in Biology FY 2017: Mechanisms of phenotypic variation in Polistes paper wasps

Miller Sara E, Ithaca NY

Investigators

Abstract

This is an NSF Postdoctoral Research Fellowship in Biology, under the program Research Using Biological Collections. The fellow, Sara Miller, is conducting research and receiving training that utilizes biological collections in innovative ways, and is being mentored by two sponsoring scientists at two host institutions: Michael Sheehan at Cornell University and James Highman at New York University. Character displacement is an evolutionary change in phenotype that results in decreased competition between species using the same resources or the same signals for mate choice. This process has been proposed as a key mechanism for maintaining biodiversity because it allows species to coexist that would otherwise go extinct through competition. Character displacement has been poorly examined in social insects. The United States is home to sixteen native species of paper wasps in the genus Polistes. These charismatic species exhibit striking diversity of color variation within and among species, yet occupy the same ecological niche and can have overlapping distributions. This project will provide a comprehensive overview of inter- and intraspecific color pattern diversity in these species. The fellow will test if these patterns are consistent with character displacement and will explore alternative hypotheses to explain this variation. This project will produce improved distribution maps, and detailed data on coloration and size variation for these species and will additionally develop image analysis methods that can be applied to other organisms. Data will be used to develop identification resources for researchers and citizen scientists. The fellow will mentor undergraduate students and present findings to local residents at Insectapalooza. Thousands of paper wasp specimens are available in museum collections making this an unexploited resource ideally suited to large-scale studies of phenotypic variation. The fellow will compile specimen information and use ecological niche modeling to generate species distribution maps. Measurements of body size and high-resolution photographs will be taken for most specimens. Automated image processing will be used to measure and quantify color pattern variation in multidimensional space. To test for a pattern of character displacement, trait means and distributions will be compared between habitats with different species compositions. Color patterns will be compared with environmental variables and latitude to test for correlations among phenotypes and the abiotic environment. This project will also examine the process of character displacement by comparing trait distributions in species' body size and coloration before and after the recent colonization of the United States by the invasive wasp species Polistes dominula. Overall, this study will provide a much-needed assessment of the mechanisms maintaining diversity among social wasps.