I am intrigued by the impact of morphological traits on ecological interactions and species divergence patterns. Ants, and especially the widespread and diverse ant genus Polyrhachis, are ideal for investigating these topics, with species boasting a broad range of morphological types, including some with highly developed spines. I will use this charismatic group to address patterns of trait evolution, including exploring associations between spines and both speciation rates and patterns of morphological trait divergence, as well as testing the ecological functions of spinescence.
Defensive traits, diversification, and evolutionary constraint
Morphological trait divergence is often associated with speciation, and can either drive or constrain rates of species diversification. I have recently focused on testing influential hypotheses like the trade-off hypothesis and the escape-and-radiate hypothesis, as they might apply to defensive traits likes spines, across all ants as well as in the spiny ant genus Polyrhachis. Currently, I am using genome-wide ultra-conserved elements (UCEs) to infer an expanded phylogeny of Polyrhachis, and collecting morphometric and biogeographic data. Using these data, I will test different compelling hypothesis, e.g. that spine evolution has allowed this group to radiate into novel niches and regions of morphospace, or that increasing specialization in spines has evolutionary constrained some subclades to certain regions of morphospace. I am also interested in the utility of 3-D micro-ct scanning for more fully capturing shape data in a group with such extreme variation in trait states, as well as more directly exploring functional questions.
Adaptation and function of spines
(Image: Alex Wild)
Despite the prevalence of spines across a wide range of ants, the function of such spinescence (the number and length of spines) has rarely been rigorously tested. Spines are often simply assumed to serve as predator deterrence, but several other forces could potentially drive spine evolution, including intraspecific competition or even arial parasitoids. Furthermore, processes such as an ecological trade-offs may influence diversification and ecological interactions in this group.
I am developing methods for testing the function of spines in Polyrhachis, including chamber experiments for intraspecific and predator-prey trials. In particular, I will use these methods to investigate the relative roles of competition and predation as selection forces potentially driving spine evolution. This work will be conducted at the Xishuangbanna Tropical Botanical Gardens in Yunnan, China, with assistance from local collaborators.
Ants, Bison, and Fire on Konza Prairie
(Previous work from senior thesis at University of Michigan)
(Image: Benjamin Blanchard)
Konza Prairie is a natural tallgrass prairie in northeastern Kansas, and also a Long Term Ecological Research (LTER) site. A large portion of the prairie has been divided into plots that vary in grazing (presence or absence of native bison) and burn regime (1-, 2-, 4-, or 20-year burn). This system is therefore ideal for studying influences of habitat heterogeneity on biological communities. In collaboration with Dr. Anthony Joern at KSU, I am investigating the impacts of bison grazing and fire frequency on ant species diversity and community composition, as well as compiling a species list for the prairie.