OVARIAN HORMONES AND THE SEXUAL BEHAVIOUR OF THE MALE RHESUS MONKEY (MACACA MULATTA) UNDER LABORATORY CONDITIONS

SUMMARY Male sexual behaviour was studied quantitatively by observing pairs of oppositely sexed, adult rhesus monkeys during regular hourly test sessions over 2 yr.; at all other times the animals were housed singly. Rhythmic fluctuations in the mounting behaviour of males occurred in relation to the menstrual cycles of female partners. Two patterns were seen: those with high and low levels of mounting, respectively, in follicular and luteal phases, and those with more isolated maxima near mid-cycle. Ejaculation times were shortest and mounting rates highest near ovulation. Bilateral ovariectomy of females abolished all rhythmic variations in the behaviour of the males, which also stopped ejaculating. Subcutaneous injections of oestradiol into ovariectomized females restored the sexual performance of males, an effect which was partly antagonized by the subsequent addition of progesterone. These findings indicate that sexual behaviour in a male primate is influenced, in some way, by the secretory activity of the female's ovaries.

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OVARIAN HORMONES AND THE SEXUAL BEHAVIOUR OF THE FEMALE RHESUS MONKEY (MACACA MULATTA) UNDER LABORATORY CONDITIONS

Journal of Endocrinology ◽

10.1677/joe.0.0410407 ◽

1968 ◽

Vol 41 (3) ◽

pp. 407-NP ◽

Cited By ~ 51

Author(s):

R. P. MICHAEL ◽

J. WELEGALLA

Keyword(s):

Menstrual Cycle ◽

Sexual Behaviour ◽

Rhesus Monkeys ◽

Ovarian Hormones ◽

Subcutaneous Injections ◽

Behavioural Interactions ◽

Female Rhesus Monkey ◽

Males And Females ◽

Low Levels ◽

Types Of Change

SUMMARY Male and female sexual behaviour was studied quantitatively by observing pairs of oppositely sexed, adult rhesus monkeys during regular hourly test sessions over 2 yr.; at all other times the animals were housed singly. Rhythmic fluctuations in the sexual invitations of both males and females, and in the refusal reactions of females, occurred in relation to the menstrual cycle. A decline in male mounting activity occurred during the luteal phase of the cycle, and resulted from two principal types of change in male—female interaction: in one, males stopped making mounting attempts, although females continued inviting (loss of female attractiveness), and in the other, males continued to attempt to mount, but females stopped inviting and began refusing (loss of female receptivity). Bilateral ovariectomy of females abolished all rhythmic variations, and the behavioural interactions were reduced to low levels; these were restored by subcutaneous injections of oestradiol into the females. These findings indicate that sexual invitations in a female primate are mediated by ovarian hormones, and that the changes in male—female interaction during the menstrual cycle can be understood in terms of endocrine-dependent changes in sexual invitations and their outcome.

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THE SUPPRESSION OF MOUNTING BEHAVIOUR AND EJACULATION IN MALE RHESUS MONKEYS (MACACA MULATTA) BY ADMINISTRATION OF PROGESTERONE TO THEIR FEMALE PARTNERS

Journal of Endocrinology ◽

10.1677/joe.0.0410421 ◽

1968 ◽

Vol 41 (3) ◽

pp. 421-431 ◽

Cited By ~ 55

Author(s):

R. P. MICHAEL ◽

G. S. SAAYMAN ◽

D. ZUMPE

Keyword(s):

Menstrual Cycle ◽

Macaca Mulatta ◽

Sexual Behaviour ◽

Luteal Phase ◽

Rhesus Monkeys ◽

Marked Decrease ◽

Sexual Interaction ◽

Female Receptivity ◽

Female Partners ◽

Male Rhesus

SUMMARY Sexual behaviour was studied quantitatively by observing six pairs of oppositely sexed, adult rhesus monkeys during 209 hourly test sessions conducted over a period of 7 months; at all other times, animals were housed singly. The effect on male—female sexual interaction was studied when ovariectomized, oestrogen-treated females were given s.c. injections of progesterone. Administration of 25 mg. progesterone resulted in a highly significant decrease in male mounting activity, in ejaculation, and in the number of sexual invitations made by females. At the same time there was a highly significant increase in the number of female refusal reactions. In three pairs, mounting attempts by males remained constant and the decline in the number of mounts resulted primarily from a large increase in refusal reactions. In three other pairs, the decline in the number of mounts resulted, primarily, from a marked decrease in male mounting attempts. The two principal mechanisms, loss of female receptivity and loss of female attractiveness, previously observed during the luteal phase of the female's menstrual cycle, were thus reproduced by giving progesterone to the ovariectomized, oestrogen-treated female partners.

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Factors influencing sexual performance in male rhesus monkeys.

Journal of Comparative and Physiological Psychology ◽

10.1037/h0077379 ◽

1977 ◽

Vol 91 (4) ◽

pp. 697-710 ◽

Cited By ~ 25

Author(s):

Charles H. Phoenix

Keyword(s):

Rhesus Monkeys ◽

Sexual Performance ◽

Factors Influencing ◽

Male Rhesus

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Changes in the Sexual Behaviour of Male Rhesus Monkeys (M. mulatta) at Puberty

Folia Primatologica ◽

10.1159/000155554 ◽

1973 ◽

Vol 19 (5) ◽

pp. 384-403 ◽

Cited By ~ 10

Author(s):

R.P. Michael ◽

Margo Wilson

Keyword(s):

Sexual Behaviour ◽

Rhesus Monkeys ◽

Male Rhesus

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PERIPHERAL PLASMA LEVELS OF OESTRONE, OESTRADIOL-17β AND PROGESTERONE DURING OVULATORY MENSTRUAL CYCLES IN THE RHESUS MONKEY WITH SPECIAL REFERENCE TO THE ONSET OF MENSTRUATION

Acta Endocrinologica ◽

10.1530/acta.0.0740732 ◽

1973 ◽

Vol 74 (4) ◽

pp. 732-742 ◽

Cited By ~ 11

Author(s):

William T. K. Bosu ◽

Elof D. B. Johansson ◽

Carl Gemzell

Keyword(s):

Macaca Mulatta ◽

Plasma Levels ◽

Luteal Phase ◽

Rhesus Monkeys ◽

Vaginal Bleeding ◽

Follicular Phase ◽

Menstrual Cycles ◽

Peripheral Plasma ◽

The Mean ◽

Low Levels

ABSTRACT The levels of oestrone (E1)*, oestradiol-17β (E2) and progesterone (P) were determined simultaneously by radioimmunoassay in serial peripheral plasma samples from 11 rhesus monkeys (Macaca mulatta) during ovulatory menstrual cycles. In 3 other monkeys luteectomy was performed on day 20 or 21 of the menstrual cycle. The mean plasma levels of oestradiol-17β predominated over the mean E1 during the follicular phase, but during the luteal phase the E1 and E2 patterns varied widely. Before menstruation, increased or unchanged levels of E1 and E2 were mostly found. The decrease found in a few monkeys never reached the low levels found during the days after the midcycle peak. The plasma levels of progesterone increased from less than 0.2 ng/ml during the follicular phase to maximal values within 3 to 4 days after the midcycle peak of oestradiol-17β. The plasma levels of progesterone decreased to less than 1 ng/ml and remained low for 3 to 5 days before menstruation. In the luteectomized monkeys the plasma levels of P, E1 and E2 fell dramatically within 24 h and vaginal bleeding was detected within 72 h post-operatively. In 2 of the 3 luteectomized monkeys the levels of E1 and E2 increased before the bleeding. The ratio of oestrogens (oestradiol-17β and oestrone) over progesterone changed markedly in favour of the oestrogens during the pre-menstrual period. It is concluded that the patterns of progesterone and oestrogens are divergent during the luteal phase. The maximal levels of progesterone are reached early while the maximal levels of oestrogens are reached later during the luteal phase.

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OVARIAN HORMONES AND GROOMING BEHAVIOUR IN THE RHESUS MONKEY (MACACA MULATTA) UNDER LABORATORY CONDITIONS

Journal of Endocrinology ◽

10.1677/joe.0.0360263 ◽

1966 ◽

Vol 36 (3) ◽

pp. 263-279 ◽

Cited By ~ 48

Author(s):

R. P. MICHAEL ◽

J. HERBERT ◽

J. WELEGALLA

Keyword(s):

Menstrual Cycle ◽

Macaca Mulatta ◽

Rhesus Monkeys ◽

Ovarian Hormones ◽

Subcutaneous Injections ◽

Male And Female ◽

The Social ◽

Endocrine Factors ◽

Grooming Behaviour ◽

Subsequent Addition

SUMMARY Grooming behaviour was studied quantitatively by observing pairs of oppositely sexed, adult rhesus monkeys during regular hourly test sessions over 2 yr.; at all other times the animals were caged singly. Rhythmic fluctuations in both male and female grooming occurred in relation to the menstrual cycle; the grooming times of males reached a maximum near mid-cycle, at which time the females' grooming was at a minimum. In some pairs, there were additional changes in the grooming times immediately before menstruation in the same direction as those near mid-cycle. Bilateral ovariectomy of the female of the pair abolished all rhythmic variations and reduced the grooming of the males. Subcutaneous injections of oestradiol into the ovariectomized female restored the grooming of males to the levels seen near mid-cycle. The subsequent addition of progesterone partially, but always consistently, antagonized the effects of oestradiol. Analysis of the hormone-induced alterations in grooming behaviour indicates a primary influence on the effectiveness of the grooming invitations of females, the proportion accepted by males increasing with oestradiol administration. These findings indicate that endocrine factors play a role in regulating grooming activity which constitutes an important aspect of the social behaviour of primates.

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