Puni Jeyasingh
Research Statement:
“All things are connected. Whatever befalls the Earth, befalls the children of the Earth”
- Chief Seattle (1786-1866).
This succinct quote captures the essence of eco-evolutionary processes – it is complex, and it transcends time. My research attempts to understand the causes and consequences of eco-evolutionary processes affecting extant biota and ecosystems by integrating information from diverse realms within biology. More specifically, I am interested in understanding how species (and various genotypes within species) utilize (i.e., ingest, assimilate and excrete) biologically important elements (e.g., carbon, phosphorus). Moreover, I am interested in understanding how differential utilization of these elements affect: (i) gene families involved in major metabolic pathways, (ii) individual behavior and physiology, (iii) population structure, (iii) community dynamics, and (iv) ecosystem functioning. These disciplines have been cornerstones of eco-evolutionary research, however, information from these diverse realms have remained isolated for decades. Present day technology (e.g., molecular tools, hi-speed imaging, ultra-sensitive probes, microbalances etc.) provides us the opportunity to rigorously test hypotheses for understanding how eco-evolutionary mechanisms operate at different levels of organization (i.e., molecules, individuals, populations, communities, and ecosystems) with a great deal of precision, rapidly.
Conceptual Framework:
I utilize the framework of ecological stoichiometry (ES) to aid in designing, executing and interpreting these integrative studies. ES is based on the laws of thermodynamics, and the following key biological observations/logic: (i) organisms require elements to live and reproduce, (ii) availability of certain elements (e.g., phosphorus, P) is highly variable spatiotemporally, (iii) there is variability in demand for various elements ontogenetically, phylogenetically, as well as at the population level (i.e., genotypic variation). Understanding the causes and consequences of such variation in elemental availability and demand is of central interest to diverse disciplines such as ecosystem ecology, and population genetics. Therefore, ES is a useful framework to probe eco-evolutionary questions at different levels of organization. Such integrative studies should improve consilience (sensu WIlson 1998) in ecological and evolutionary thought.
Model element:
I have chosen to focus primarily phosphorus (P), because although scarce in the known universe and biosphere (micromolar concentration), P is ubiquitous, and performs critical functions within living systems (often in millimolar concentrations). This observation has led chemical evolutionists to implicate cometary delivery of P as a precursor for the origin of early biomolecules. The physico-chemical properties of P predispose it to be a critical component of many key compounds that carry out basic biochemical processes such as: nucleic acids that transmit genetic information, nucleotides that are precursors in DNA and RNA synthesis, phospholipids that make up the cell membrane, sugar phosphates which are key molecules in carbohydrate metabolism, and adenosine tri-phosphate (ATP) as a primary cellular energy source. Further, P also plays important structural roles such as in vertebrate skeletons, scales etc. These central roles of P in the structure and functioning of primary biological components suggest that the lack of P, and the subsequent structural and functional consequences in these basic cellular components should affect individual fitness.
Model system:
I use the freshwater microcrustacean Daphnia as my model organism to test integrative hypotheses. Daphnia provides an ideal system to develop and test integrative hypotheses: (i) they are dominant grazers in lentic systems, (ii) they have high genotypic diversity, (iii) numerous molecular markers are available, and the genome of D. pulex is sequenced, (iv) most daphniids are cyclical parthenogens, therefore controlling for the genetic background, and propagation in the lab is rather easy, and finally (v) plethora of information on daphniid natural history from all over the world is available.
Selected publications (click titles for .pdf):
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.
Jeyasingh, P.D. & C.A. Fuller (2004). Habitat-specific life-history variation in the Caribbean termite Nasutitermes acajutlae (Isoptera: Termitidae). Ecological Entomology 29 (5): 606-613
Jeyasingh, P.D., & P. Davidar (2003). Crop depredation by wildlife along the Eastern boundary of the Kalakad-Mundanthurai Tiger Reserve, Southern India.Journal of the Bombay Natural History Society 100 (1): 38 – 45.
“Whatever you do will be insignificant, but it is very important that you do it"
- Mohandas K. Gandhi (1869-1948)
Ph.D. (2007). University of Oklahoma.
M.S. (2003). Murray State University.
M.S. (1999). Pondicherry University.
B.Sc. (1997). Madras Christian College.
Puni Jeyasingh
Post-doctoral associate,
Department of Ecology, Evolution & Behavior,
University of Minnesota,
100 Ecology Building,
1987 Upper Buford Circle,
St. Paul, MN 55108. U.S.A.
Phone: (612) 624-6711.
Department of Ecology, Evolution & Behavior,
University of Minnesota,
100 Ecology Building,
1987 Upper Buford Circle,
St. Paul, MN 55108. U.S.A.
Phone: (612) 624-6711.
Conceptual schematic of an elemental approach to evolutionary ecology.
Photo-series demonstrating the growth and fecundity penalties faced by D.pulex under P-limitation.
Slow-motion (~10x slower) micro-videograph of a D.magna feeding on algae.
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