DISSERTATION RESEARCH: Morphological evolution, specialization, and functional ecology in a diverse genus of ants

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This project will address a fundamental question in biology: the mechanisms that allow many species to persist in any single environment. Ants are highly diverse in many different habitats and are important for ecological processes worldwide. To understand what promotes the persistence of ant diversity, the association between physical traits, such as spines and stings, and ecological interactions, like competition and defenses against predators, must be experimentally determined. This project will investigate one of the most widespread and commonly encountered ant groups in tropical Africa, Asia, and the Pacific, the spiny ant, Polyrhachis. Using ecological field experiments, this research will assess the effect of a wide range of anatomical defenses on ant competition and anti-predator defense. It will contribute to our understanding of the mechanisms that promote biodiversity in tropical habitats. Furthermore, this project will foster international collaborations between researchers in the U.S. and those in China. The researchers will also actively participate in numerous outreach and public engagement opportunities in Chicago, including various science education programs at the Field Museum of Natural History, and academic tutoring of middle and high school students from groups that are underrepresented in the sciences.To elucidate the ecological selective forces driving spine adaptation and specialization in Polyrhachis, the researchers will conduct a series of competition and predator-prey experiments at the Xishuangbanna Tropical Botanical Garden (XTBG) in Yunnan, China. These experiments will include a range of species that are present at this site and that span the full range of spine morphology, from absent to extremely long. In the first set of tests, the researchers will assess the impact of spines on interspecific ant competition. In the second, the researchers will quantify the survival benefit conferred by spines as defenses against frog predators. These experiments will be conducted in the lab using colonies collected in the field. A common chamber design with experimental spine length manipulation will allow for differentiating the survival effects of spine length in terms of two fundamental ecological interactions. Using data from these experiments, the researchers will evaluate the evidence for an ecological trade-off between competitive ability and anti-predator defense mediated by spines. These empirical tests of the trade-off hypothesis in Polyrhachis, a remarkable animal radiation, will expand scientific understanding of the processes that promote community coexistence and ecological success.