Research Interests
Our quest for a fundamental understanding of eco-evolutionary processes has become an integrative endeavor - there are more questions than answers. I strive to provide an intellectual milieu that will stimulate students to join me and my colleagues in pursuing such broad interdisciplinary challenges.
One way to integrate information from seemingly disparate disciplines is by analyzing the dynamics of biogenic elements (e.g., Carbon, Phosphorus, among others) that make up, and are exchanged between and among: molecules, cells, organs, individuals, populations, communities and ecosystems. Organisms acquire these elements from the environment, assimilate and allocate them to critical fitness-relevant structures and functions, and excrete the unused atoms back into the environment. Much is known about the dynamics of elements at various levels of organization (e.g., cellular physiology, agronomy, biogeochemistry). Nonetheless, a synthesis of such information still eludes us largely because we lack data directly bridging levels of organization. With environmental supply, and somatic demand of key biogenic elements as a point of departure, I am broadly interested in: intracellular gene expression, intercellular signaling and transport, inter-organ and/or -function allocation, individual behavior and physiology, population genetics, and consumer-driven nutrient recycling. Students have the academic freedom to pursue their own curiosities, in any system, and at any level of organization. My job is to nurture and support such budding academic pursuits.
Personally, I am fascinated by the challenge of synthesizing information on the processing of elements at different levels of organization for a fundamental understanding of how these multi-level mechanisms generate, maintain and erode genotypic and phenotypic variation. Such a pursuit has lead me to (among other efforts): observe Daphnia forage on algae differing in elemental content using high-speed video imaging, use radioisotopes to track the physiological fate of elements, track the frequency of enzyme polymorphisms under contrasting elementally-defined conditions, generate and analyze transcriptomes, and even paddle into a partially frozen lake in an inflatable dinghy!
There are more questions to answer, and many more tools to learn. Currently, in collaboration with Larry Weider at the University of Oklahoma, efforts are underway to pursue questions regarding the role of cultural eutrophication in the microevolution of Daphnia using radio isotopes, life-tables, qPCR, transcriptomics, and resurrection ecology. In addition, I am collaborating with Rickey Cothran at the University of Pittsburgh to understand how limiting elements affect the expression of a sexually selected trait in Hyallela, a common freshwater amphipod.
Selected Publications
Hessen, D.O., P.D. Jeyasingh, M. Neiman, L.J. Weider (in press).Genome streamlining and the elemental costs of growth. Trends in Ecology and Evolution.
Jeyasingh, P.D., L.J. Weider, R.W. Sterner (2009). Genetically-based trade-offs in response to stoichiometric food quality influence competition in a keystone aquatic herbivore. Ecology Letters 12(11): 1229–1237.
Weider, L.J., P.D. Jeyasingh & K.G. Looper (2008). Stoichiometric differences in food quality: impacts on genetic diversity and the coexistence of aquatic herbivores in a Daphnia hybrid complex. Oecologia.158(1): 47-55.
Jeyasingh, P.D., & L.J. Weider (2007). Fundamental links between genes and elements: evolutionary implications of ecological stoichiometry. Molecular Ecology 16 (22): 4649-4661.
Jeyasingh, P.D. (2007). Plasticity in metabolic allometry: the role of dietary stoichiometry. Ecology Letters 10(4): 282-289.
Jeyasingh, P.D., & L.J. Weider (2005). Phosphorus availability mediates plasticity in life-history traits and predator-prey interactions in Daphnia. Ecology Letters 8(10): 1021-1028.
