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Associate Professor of Zoology
Phone: (405)325-4389
Fax: (405)325-6202RM/Lab:RH108
Dr. Knapp's web page
Current Research Interests and Subject Areas Available for Graduate Research
My research aims to understand the physiological, ecological and evolutionary factors contributing to behavioral variation, with an ultimate aim of increasing our understanding of how behavior evolves. I combine the approaches of behavioral endocrinology, neuroendocrinology and physiological ecology to study the bases of behavior by studying both in the field and in the laboratory, most recently with several species of lizards and fish. My research has been centered on questions related to the physiological bases of variation in aggressive and reproductive behavior, with two main foci: 1) variation in androgen-glucocorticoid interactions in the context of alternative male reproductive tactics and 2) endocrinology of male parental behavior. My focus has been on steroid hormones because of their important role as chemical messengers that mediate behavioral, physiological and developmental processes. I have concentrated on interactions between the stress and reproductive endocrine axes because these axes mediate some of the major costs and benefits associated with male reproductive behavior.
Alternative male reproductive tactics
To investigate the proximate bases of intrasexual variation in behavior, I focus on species in which males exhibit discrete alternative reproductive tactics. In these species, males achieve reproductive success by one of generally two distinct tactics: a displaying, territorial tactic or one or more non-displaying “cuckolder” tactics. In many of these species, the behavioral variation is tightly correlated with morphological variation, with one male “morph” exhibiting the entire suite of sexually dimorphic characters typically considered male-typical and one or more morphs that are female-like in the _expression of some secondary sex characters. These species have received much attention in the behavioral ecology literature, but little is known about the physiological mechanisms contributing to such intra-sexual variation. One area for which such species may be particularly useful is in examining the interaction between glucocorticoids and androgens in mediating responses, especially reproductive behavior and function, to stressful environmental stimuli. My current efforts in this are area focused mainly on bluegill and longear sunfish.
Male parental behavior
My work with fish has led to research on the endocrine bases of paternal behavior. In many species of fish, the males provide all of the parental care. I am interested in how hormone-behavior relationships vary across species that differ in whether or not the males must simultaneously provide parental care and court additional females for spawning. For example, sunfish males spawn with multiple females on a single day whereas plainfin midshipman spawn with a single female on a given night, but will spawn for several nights in a row. In collaboration with Byran Neff (University of Western Ontario) and Andrew Bass (Cornell University), we’ve found that sunfish and midshipman, respectively, differ in their androgen and cortisol profiles over the period of parental care. Current studies are investigating the physiological and behavioral underpinnings of these differences
To learn more about this research, visit Dr. Knapp's web page
M.S., University of Wisconsin-Madison
B.S., Cook College, Rutgers University
Member, Oklahoma Center for Neuroscience
Selected publications:
Leary CJ, Garcia AM, Knapp R. 2006. Female toads and sexual parasites choose males with low levels of stress hormone: dynamic tradeoffs and potential constraints on sexually selected traits. American Naturalist, 168(4):431-440.
Magee SE, Neff BD, Knapp R. 2006. Plasma levels of androgens and cortisol in relation to breeding behavior in parental male bluegill sunfish, Lepomis macrochirus. Hormones and Behavior, 49(5): 598-609.
Sisneros JA, Forlano PM, Knapp R, Marchaterre MA, Bass AH. 2004. Seasonal changes in steroid hormone concentrations in a substrate spawning, vocal teleost, the plainfin midshipman. General and Comparative Endocrinology, 136(1):101-116.
Knapp R. 2003. Endocrine mediation of vertebrate alternative male reproductive phenotypes: the next generation of studies. Integrative and Comparative Biology, 43(5):658-668.
Knapp R, Hews DK, Thompson CW, Ray LE, Moore MC. 2003. Environmental and endocrine correlates of tactic switching by nonterritorial male tree lizards (Urosaurus ornatus). Hormones and Behavior, 43(1):83-92.
Knapp R, Wingfield JC, Bass AH. 1999. Steroid hormones and paternal care in the plainfin midshipman fish (Porichthys notatus). Hormones and Behavior, 35(1):81-89.
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