Hormonal Control of Sexual Behavior Laboratory Animals Female Sexual Behavior

Hormonal Control of Sexual Behavior Laboratory Animals Female Sexual Behavior The female will also move her tail away(if she has one) and stand rigidly enough to support the weight of the male • If a male attemptsto copulate with a nonreceptive rodent, the female will either actively flee or rebuff him. • When the female is in a receptive state, she will often approach the male, nuzzle him, sniff his genitals, and show behaviors characteristicof her species à quick, short, hopping movements and rapid ear wiggling. • Lordosis – estradiol. Hormonal Control of Sexual Behavior Laboratory Animals Female Sexual Behavior

9/9/16 26 • In rats, estradiol increases about 40 hours before the female becomes receptive; and just before receptivity occurs, the corpus luteum begins secreting large quantities of progesterone. • Ovariectomized rats (ratswhose ovaries have been removed) arenot sexually receptive. • Receptivity can be produced in ovariectomized rodents by administering large doses of estradiol alone • The most effective treatment duplicates the normal sequence of hormones: a small amount of estradiol, followed by progesterone. Hormonal Control of Sexual Behavior Laboratory Animals Female Sexual Behavior • Progesterone does not rescue receptivity in ovariectomized rats. • Priming with estradiol takes about 16–24 hours, after which an injection of progesterone produces receptive behaviors within an hour. • Rissman et al., (1997): female mice without estrogen receptors wereunreceptive to males even after treatment with estradiol and progesterone. • Lydon et al. (1995) female mice without progesterone receptors = unreceptive to males even after treatment with estradiol and progesterone. Hormonal Control of Sexual Behavior Laboratory Animals Female Sexual Behavior

9/9/16 27 • Estradiol + Progesterone = 3 effects on female rats. • Receptivity à ability and willingness to copulate—to accept the advances of a male by holding still and displaying lordosis when he attempts to mount her. • Proceptivity à female ’ s eagerness to copulate = seeks out a male and engages in behaviors that tend to arouse his sexual interest. • Attractiveness à physiological and behavioral changes that affect the male. The male rat is most responsive to females who are in estrus. Hormonal Control of Sexual Behavior Laboratory Animals Female Sexual Behavior • Males will ignore a female whose ovaries have been removed, but injections of estradiol and progesterone will restore her attractiveness (and also change her proceptivity and receptivity toward the male). • The stimuli that arouse a male rat ’ s sexual interest = odor and behavior. • In some species, visible changes, such as swollen skin in the genital region of a female monkey, also affect sex appeal. Hormonal Control of Sexual Behavior Laboratory Animals Female Sexual Behavior