Courtship-induced changes in female sexual receptivity : a neuroendocrine study in an amphibian
the effects of courtship on the neuroendocrine system of
female rough-skinned newts, Taricha granulosa, and 2)
whether the observed courtship-induced neuroendocrine
changes affected female sexual receptivity.
Sexual behaviors of female T. granulosa changed
dramatically during courtship. Initially, females
exhibited unreceptive behaviors to a courting male. After
several hours of courtship, females displayed receptive
behaviors, and males responded by attempting to transfer a
sperm cap. Once courtship, insemination and post-insemination
behaviors were complete, the female no longer
became receptive to future courtship.
Both telencephalic irLHRH and plasma estradiol
concentrations changed as females became receptive. Early
in courtship, when females were unreceptive, irLHRH
concentrations in the telencephalon were elevated, but by
the time females became receptive irLHRH concentrations
were low. The change in telencephalic irLHRH
concentration occurred in the nervus terminalis, a little
understood cranial nerve that may influence reproduction.
Plasma estradiol levels were low at courtship initiation,
but were elevated by the time females became receptive.
The observations, that irLHRH and estradiol concentrations
were associated with changes in female sexual behaviors
and that these hormones influence female sexual
receptivity in other vertebrates, suggested that courtship
by a male activates female sexual behavior by stimulating
endogenous changes in LHRH and estradiol.
Increasing or decreasing plasma estradiol
concentrations or blocking the action of this steroid in
the brain were found to have no effect on female
receptivity. Also, injecting LHRH or LHRH analogs into
brain was found to have no effect on female receptivity.
Progesterone implantation inhibited receptivity suggesting
that this steroid may be responsible for the post-insemination
decrease in female sexual behavior. These
results suggest that although courtship induces
physiological changes in female T. granulosa, the changes
in LHRH and estradiol may not be influencing receptivity.
Advisor:Moore, Frank L.; Blaustein, Andy; Lubchenco, Jane; Schreck, Carl; Evans, Tom
School:Oregon State University
School Location:USA - Oregon
Source Type:Master's Thesis
Keywords:reproduction endocrine aspects courtship of animals sexual behavior in taricha granulosa
Date of Publication:12/14/1988