My current research focuses on the energy and water balance in ectoparasitic arthropods, specifically ticks and fleas. I am primarily concerned with the question of how the off-host developmental stages of ectoparasitic arthropods such as ticks and fleas manage to survive for long periods (ranging from weeks to several years) between blood meals.
Ticks as a group survive longer than any other arthropod without food or drinking water. The key issue to off-host survival is effective and stringent control of energy and water reserves accomplished through slow metabolism, water conservation and active water uptake. My research seeks to answer questions about metabolic mechanisms that facilitate energy conservation in ticks. My main collaborator is Yigal Rechav, Visiting Scholar at Truman State University
Ygall Rechav
Flea Research
Work on fleas has included extensive collaboration with Boris Krasnov (Ben Gurion University of the Negev, Israel http://www.bgu.ac.il/desert_ecology/ramon/krasnov.html
Our work has centered on examining interspecific differences in physiological capabilities of fleas to survive the off-host environment and how this ability relates to observed differences in rodent-flea assemblages along an aridity gradient in the Negev desert. I expanded this research theme on energy and water balance to the cat flea, a major domestic pest in the USA. Tara Thiemann started looking at water uptake capabilities in cat fleas as an undergraduate. She is now continuing with this research as a graduate student.
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Reflections on the role of undergraduate research in the research laboratory:
I encourage biology majors to become involved in meaningful (publishable) faculty research either through honors-level research programs, summer research, independent study or as a worker in a research lab. I have supervised undergraduate research in all of these situations and have had the great pleasure of my students presenting oral presentations, winning awards at national meetings and co-authoring research publications with me.
Paula Richards – Effect of entomopathogenic fungi on tick metabolism (in collaboration with Ken Craddock, University of Ohio)
Christine Janson and Sarah Hobbs– Water and energy balance in the cat flea – why do fleas spin cocoons ?(in collaboration with Tara Thiemann, Truman State)
(student authors in bold)
Fielden L. J., Jones R.M., Goldberg, M. and Rechav, Y. 1999 Feeding and respiratory gas exhange in the American dog tick, Dermacentor variabilis. Journal of Insect Physiology 45: 297-304
Rechav, Y., Drey C., Fielden L.J. and Goldberg, M.. (2000). Production of pheromones by artificially fed males of the tick Amblyomma maculatum (Acari: Ixodidae). Journal of Medical Entomology: 37:761-765.
Fielden, L., Krasnov, B. & Khokhlova, I. 2001. Respiratory gas exchange in the flea
Xenopsylla conformis (Siphonaptera: Pulicidae). Journal of Medical Entomology 38:735-739.
Fielden, L., Krasnov, B., Still, K.& Khokhlova, I. 2002 Water balance in two species of
desert fleas, Xenopsylla ramesis and X. conformis (Siphonaptera: Pulicidae). Journal of
Medical Entomology 39: 875-881.