Department of EEOB The Harder Laboratory

The Ohio State University Department of Evolution, Ecology, and Organismal Biology 392 Aronoff Laboratory 318 W. 12th Avenue Columbus, OH 43210 Phone: 614-292-8636 Fax: 614-292-2030 Email: harder.2@osu.edu

 

 

Harder Lab Group - June 2006

 

 

 

Research Interests:

I study the reproductive biology of mammals. Marsupial and eutherian mammals exhibit fundamental differences in reproductive strategies that have prompted my work, both field and laboratory, with white-tailed deer, tammar wallabies, red howler monkeys, hamsters, and opossums. Current topics of study include: Mammalian diversity in Ohio, Reproduction and stress in tree kangaroos (Dendrolagus matschiei), and Reproductive biology and sexual differentiation of the gray short-tailed opossum (Monodelphis domestica), a small (60-150 g) pouchless marsupial native to Brazil. This opossum is particularly useful for study of olfactory regulation of reproductive processes, because females lack an estrous cycle and are reliant on nonvolatile male pheromone for reproductive activation. Our studies involve the analysis of olfactory and reproductive behavior, immunohistochemistry, and measurement reproductive hormone concentrations in blood and their metabolites in feces. We seek to understand the sexual differentiation of neuroendocrine pathways and behavior from pheromonal stimulation of the vomeronasal organ to ovarian activation, estrus, and ovulation. Current research on opossums is focused on the role of progesterone in sexual differentiation of brain and behavior.

Male opossum scentmarking	Female opossum nuzzling male scentmark

Key Citations:
Jackson, L.M. and J.D. Harder. 2000. Evidence for spontaneous postlactational estrus in gray short-tailed opossums (Monodelphis domestica) Biol. Reprod. 62: 1823-1827.
Fadem, B.H., D.R. Dziadosz, L.M. Jackson, and J.D. Harder. 2000. Male choice by intact and ovariectomitzed female gray short-tailed opossums (Monodelphis domestica). Hormones and Behavior. 38: 187-192.
Herrick, J. and J.D. Harder. 2000. Urinary progesterone in free-ranging red howler monkeys (Alouatta seniculus): preliminary observations of the estrus cycle and gestation. Am. J. Primatology.51: 257-263.
Harder, J.D., Y. He, N. Pizza, and B.H. Fadem. 2001. Luteinizing hormone response to pairing in gonadectomized, estradiol-treated female and male gray short-tailed opossums (Monodelphis domestica). Hormones Behavior Abst. 39:332.
Harder, J.D., and L.M. Jackson. 2003. Male pheromone stimulates ovarian follicular development and body growth in juvenile female opossums (Monodelphis domestica). Reproductive Biology and Endocrinology 1:21-29.
Harder, J.D., L.M. Tadros, Y. Rogier, J.R.Norfolk, and B.H. Fadem. 2005. Male-induced rise in progesterone precedes receptivity and ovulation in the gray short-tailed opossum (Monodelphis domestica). Biol. Reprod. 72 (Suppl.1): 225-226.
Harder, J.D. 2005. Reproduction and hormones. p 591-615 in C.E.Braun, ed. Techniques for wildlife investigations and management. Sixth Edition., The Wildlife Soc. Bethesda, MD.

John Harder's EEOB Faculty Webpage

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Course Websites:

• EEOB 661
• EEOB 625

Employment Opportunities:

• Mammalian diversity in Ohio: Work Study EEOB #156
• Distribution of thirteen-lined ground squirrels in central Ohio: (EEOB 693)