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Key Event Title
Sexual behavior, decreased
|Level of Biological Organization|
Key Event Components
Key Event Overview
AOPs Including This Key Event
|AOP Name||Role of event in AOP||Point of Contact||Author Status||OECD Status|
|Inhibition of CYP7B activity leads to decreased sexual behavior||KeyEvent||Arthur Author (send email)||Not under active development|
|Adult, reproductively mature|
Key Event Description
Sexual behavior in male bird is characterized by components such as crowing, strutting, and mounting, whereas the newt exhibits a tail-vibrating behavior (Hutchison, 1978). In both species, sexual behavior varies on a daily (photoperiod) and seasonal (breeding) basis. A decrease in sexual behavior is defined by a reduction in the frequency of these typical behaviors.
How It Is Measured or Detected
Since sexual behavior varies along the day and the season, timing is an important component of the measurement. Light exposure, endocrine disruptors and season should all be considered in the protocol design in order to limit the bias in the measurement.
Sexual behavior in male is measured in presence of a sexually receptive female. To limit the risk of bias induced by differences in female receptivity, it is important to repeat the experiment later/the day after with a different female for each male (Halldin et al., 1999).In bird, the frequency of chasing, pecking, head grabbing, and mounting for a X minutes observation can be measured (Halldin et al., 1999; Ogura et al., 2016).
For newt, sexual behavior is characterized by a tail-vibrating behavior and can be measured by counting the frequency and incidence of this behavior during X minutes. Incidence and frequency are expressed as the percentage of animals exhibiting the behavior and the mean number of times the behavior was recorded per test animal over the test period, respectively (Toyoda et al., 1983).
Domain of Applicability
This key event can be applied to any animal having sexual reproduction. It does not apply to asexual animals.
Adkins, E. K. and N. T. Adler. 1972. Hormonal control of behavior in the Japanese quail. J. Comp. Physiol. Psychol.81:27-36.
Halldin, K., Berg, C., Brandt, I., and Brunstrom, B. (1999). Sexual behavior in Japanese quail as a test end point for endocrine disruption: effects of in ovo exposure to ethinylestradiol and diethylstilbestrol. Environ Health Perspect 107, 861-866.
Hutchison, R.E. (1978). Hormonal differentiation of sexual behavior in Japanese quail. Horm Behav 11, 363-387.
Ogura, Y., Haraguchi, S., Nagino, K., Ishikawa, K., Fukahori, Y., and Tsutsui, K. (2016). 7alpha-Hydroxypregnenolone regulates diurnal changes in sexual behavior of male quail. Gen Comp Endocrinol 227, 130-135.
Sachs, B.D. (1967). Photoperiodic control of the cloacal gland of the Japanese quail. Science 157, 201-203.
Toyoda, F., Ito, M., Tanaka, S., and Kikuyama, S. (1993). Hormonal induction of male courtship behavior in the Japanese newt, Cynops pyrrhogaster. Horm Behav 27, 511-522.