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PubMed1982

Copulation increases offensive attack in male rats.

Twenty-four adult male rats with previous sexual experience were tested for aggression against intruders after one of four treatments (n = 6 per treatment): exposure to inaccessible estrous females; exposure to anestrous females; no female exposure, or copulation to ejaculation. Although both exposure to inaccessible estrous females and copulation significantly decreased latency to attack only copulation produced significant elevation of intensity and duration of attack. Results are discussed in reference to the role of aggression in maintaining priority of access to females, and as a means of assuring paternity of offspring by dominant males.

Aggression↗
PubMed1990

Systemic or intracranial apomorphine increases copulation in long-term castrated male rats.

Testosterone or its estrogenic metabolite is thought to be necessary to activate male rat sexual behavior. However, systemic injections of dopamine agonists, alone or in combination with exogenous testosterone, can partially restore copulatory behavior during the prolonged period of its postcastration decline. The present experiments tested the ability of the dopamine agonist apomorphine, injected systemically or into the medial preoptic area (MPOA), to restore copulation in long-term castrates that had failed to copulate on two successive weekly tests. In Experiment 1, systemic injections of apomorphine increased the number of mounts and intromissions in castrated males, compared to vehicle. In castrates given subthreshold testosterone propionate (TP), apomorphine increased the number of mounts. In Experiment 2, microinjections of apomorphine into the MPOA increased the number of mounts in animals without TP. Subthreshold TP had no significant effects in either experiment, either alone or interacting with apomorphine. These results suggest that stimulation of dopamine receptors can partially restore copulation, even after its virtual elimination. Furthermore, dopamine receptors in the MPOA may contribute to sexual arousal in long-term castrates.

Animals↗
PubMed1991

Zona incerta lesions: effects on copulation, partner-preference and other socio-sexual behaviors.

Sexually active males prefer a sexually receptive female to a non-receptive female, and partner-preference tests provide one way of studying the effect of brain damage on sexual motivation. Male rats with bilateral electrolytic lesions of the caudal zona incerta do not mate, and we studied the effects of zona incerta destruction on copulation and partner-preference. Lesioned males did not mate but were not indifferent to sexually receptive females. They continued to show a strong preference for a sexually receptive female over a non-receptive female. In addition, lesioned males showed many incomplete mounts i.e. mounts not accompanied by the pelvic thrusting necessary for intromission and ejaculation. Anogenital investigation of the receptive female was common. Taken together, these facts suggest that zona incerta destruction eliminates copulation without affecting sexual motivation, and that the failure to mate after lesioning probably reflects an inability to properly engage the locomotor responses of copulation.

Animals↗
PubMed1978

Interaction between penile reflexes and copulation in male rats.

Intact, unanesthetized male rats were place in a supine position, with the penile sheath continuously retracted. Three forms of penile reflex were displayed: erections, cups, and flips. The reciprocal relation between copulation and the penile reflexes occurring in supine tests was explored in four experiments. In Experiment 1, sexual exhaustion depressed all penile reflexes, but the reflexes returned to baseline levels within 8 hr, long before copulatory potential. In Experiment 2, reflexes were depressed to exhaustion levels after fewer ejaculations than were required for sexual exhaustion, an indication that reflexes are more readily evoked during copulation than in supine tests. Experiment 3 determined that a rat's penile-reflex potential may be enhanced by placing the rat in a copulation-test cage, by allowing the male a few antecedent intromissions, or by allowing an antecedent ejaculation. The display of penile reflexes within 1 min after ejaculation suggests that the period of reduced sexual arousability following ejaculation is not due to reduced excitability in the spinal mechanisms controlling penile reflexes. In Experiment 4, 1 hr of penile-reflex elicitation had no effect on subsequent copulatory behavior. Thus, sexual stimulation may increase or decrease penile-reflex potential, but a reciprocal influence was not detectable.

Animals↗
PubMed1992

Treatment with mifepristone (RU486) and oestradiol facilitates the development of genital septic disease after copulation in female rats.

Ovariectomized female rats were treated with oestradiol and the progesterone-antagonist mifepristone. They allowed males to copulate to a similar extent as ovariectomized rats treated with oestradiol alone. The additional treatment with mifepristone, however, resulted in uterine infections following copulation, together with the prolonged presence of copulatory plugs in the uterine lumen. On several occasions rats became severely ill during the days after copulatory tests, occasionally with lethal consequences. Microscopic examination of the cervix and uterus 1 day after a copulation test in rats treated with oestradiol plus mifepristone, showed that copulatory plugs passed through the cervical canals directly into the uterine lumen. Bacterial infections and local destruction of the uterine epithelium were found in all rats examined. These features were not found in rats treated with oestradiol alone. Actions of mifepristone on the cervix of oestradiol treated rats are likely to play a key role in the passage of copulatory plugs and, thereafter, the development of uterine sepsis.

Animals↗
PubMed1967

Role differentiation in copulating cicada killer wasps.

Copulating male and female cicada killer wasps have distinct behavioral roles independent of reproduction. Males terminate copulation, and females initiate the copulatory flight in which the pair in copulation escape potential danger. Separation and escape behavior are mutually exclusive. Separation occurs because the female clings to the substrate and fails to join the male in his frequent attempts at flight; thus he eventually pulls free. Escape occurs when the female begins flight, which the male readily joins. Differences in thresholds for flight probably largely determine both roles. There appears to be an evolutionary balance in escape and separation behavior determined by the behavior of the female, and illustrative of behavioral homeostasis. The female remains still in the presence of mild stimuli, such as attempted male flights, and thereby aids in separation; she initiates escape in the presence of strong stimuli such as potential enemies.

Animals↗
PubMed1986

Courtship and copulation in Tarsius bancanus.

The reproductive behavior of 6 paired, captive Bornean tarsiers was studied over an 8-month period. Seven copulations were observed. Females signalled males by visual displays and olfactory cues from vulval rubbing. Males signalled females with courtship calls heard before matings. After a courtship lasting from 1 to 2 h, copulation occurred with the male thrusting 61-190 times for 60-90 s, ending in ejaculation. The female regulated timing of mating by rejection or avoidance of the male. Multiple matings were not observed, and mating occurred once or twice a night during each night of estrus. This copulatory pattern of infrequent matings of short duration and active female solicitation and regulation of copulating timing suggests a harem or monogamous system.

Animals↗
PubMed1986

A quantitative immunohistochemical study on the pituitary LH gonadotrophs in the female Afghan pika after copulation.

The female Afghan pika is known as a species of copulatory ovulators exhibiting persistent estrus unless copulatory stimuli are employed. The plasma LH concentration rose quickly after copulation, peaked at 6 h and descended thereafter until 12 h. Before copulation (estrus), immunoreactive LH-containing cells of the pituitary in this species were filled with numerous large electron dense secretory granules, but the Golgi apparatus and the granulated endoplasmic reticulum were not well developed. One hour later the stainability of the cells was faint, their secretory granules were malls in size and in number, and were of low electron density. These alterations were the most predominant at 12 h after copulation. No exocytotic extrusion of secretory granules was observed throughout the experiment.

Animals↗
PubMed1975

Plasma luteinizing hormone and testosterone in the adult male pig: 24 hour fluctuations and the effect of copulation.

Secretory patterns of LH and testosterone were characterized in the intact male miniature pig. All blood samples were taken from indwelling catheters. Hourly sampling was carried out over 24 h and during a morning period blood was collected for 2 h at 10 min intervals. No significant difference was detected in the plasma LH concentration on the basis of hourly sampling. Plasma testosterone was significantly (P less than 0-05) lower during the evening and night when compared with morning values. The second experiment was concerned with the pattern of plasma LH and testosterone concentrations before and after copulation. Blood sampling was performed at 10 min intervals. Plasma LH was significantly (P less than 0-001) raised for 30 min after copulation when compared with any 30 min period (0-120 min) before copulation. Plasma testosterone was not significantly altered for any 30 min period of the experiment (0-270 min). The data are interpreted as a possible mechanism for endocrine control of testicular function.

Animals↗
PubMed1984

The role of neurotransmitters in mediating copulation-induced ovulation in the rat.

Pentobarbitone-blocked pro-oestrous rats were subjected to either limited mating (maximum of 30 mounts), all-night cohabitation with males or stimulation of the vagina and cervix with a glass rod (2 or 5 min) to determine which type of stimulus was most effective in inducing ovulation. All-night cohabitation was the most successful procedure and resulted in 100% ovulation in those rats which mated. Treatment with either phenoxybenzamine, propranolol or pimozide did not interfere with this copulation-induced ovulation whereas methysergide treatment completely blocked copulation-induced ovulation. Administration of atropine resulted in a loss of mating behaviour and these animals therefore did not ovulate. Further experiments provided evidence that administration of atropine also blocked ovulation in response to vaginal stimulation with a glass rod. Pretreatment with methysergide or atropine had no effect upon the percentage of pentobarbitone-blocked, pro-oestrous rats ovulating in response to administration of LH releasing hormone (LHRH). However, those rats given atropine shed significantly fewer ova per rat following LHRH or LH infusion when compared with controls. These results suggest that the synaptic mechanisms responsible for mediating copulation-induced ovulation are different from those mediating steroid-induced ovulation, and that ovarian cholinergic receptors may play a role in ovulation.

Animals↗
PubMed1978

Investigation of copulative activity in male rats in chronic experiment.

Copulative activity of 28 male Wistar rats was investigated for one year at 6 to 8 day intervals. Metholds have been worked out for the selection of sexually active males. It was found that it is possible to investigate copulative activity permanently in a selected population of male rats. The sexual activity index number of intromissions/time of ejaculation can be applied to the 15-minute test. In order to evaluate individual differences observed during the experiments, the ratio positive experiments/all experiments has been used. During a one-year experimental period (791 experiments altogether) mean latency time was 56'', and that of the ejaculation 7'10''. The average number of intromissions was 7.89, and that of attempts 3.41. Ejaculation occurred 575 times. The average sexual activity index was 1.1. There was no seasonal fluctuation in copulative activity.

Animals↗
PubMedDate not supplied

Behavior of triatomines (Hemiptera: Reduviidae) vectors of Chagas' disease. II. Influence of feeding, lighting and time of day on the number of matings, mating speed and duration of copulation of Panstrongylus megistus (Burm, 1835) under laboratory conditions.

To determine the influence of feeding, lighting and time of day on the copulating behavior of Panstrongylus megistus, 480 insect pairs were divided into four groups of 120 each and tested in the following respective situations: without food deprivation (F.D.), with five days of F.D., with ten days of F.D., and with 20 days of F.D. The tests were performed between 9:00 a.m. to 12:00 a.m. and 7:00 p.m. to 10:00 p.m., with light (700-1400 lux) and in the dark (1.4-2.8 lux) and behavior was recorded by the time sampling technique. Mating speed (MS) and duration of copulation (DC) were also calculated for each situation. The maximum frequency of copulation was observed after five days of F.D., at night, in the dark (n = 16), and the minimum was observed for recently-fed pairs, at night, with light (n = 4). Males approached females more often than females approached males. MS was lowest in pairs with twenty days of F.D., at night, with light (mean = 23.0 +/- 16.0 minutes), and highest in recently-fed pairs, during the day, with light (mean = 2.9 +/- 2.5 minutes). DC was shortest in recently-fed insects, during the day, in the dark (mean = 23.5 +/- 6.7 minutes), and longest in recently-fed animals, at night, in the dark (mean = 38.3 +/- 6.9 minutes).

Animals↗
PubMed1977

Transmission of Nosema kingi to offspring of Drosophila willistoni during copulation.

Transmission of the microsporidian Nosema kingi to offspring of Drosophila willistoni during copulation was investigated. Offspring from matings of infected females and non-infected males, infected males and non-infected females, and both infected females and males were parasitized with N. kingi. 28% of the offspring were infected when the parents mated immediately after exposure to the parasite. However, 43--93% of the offspring were infected with the microsporidian when copulation was delayed 2 weeks post-infection.

Animals↗
PubMed1986

Physiological changes during copulation in male and female stumptail macaques (Macaca arctoides).

Radiotelemetric recordings were made of uterine contractions in female stumptail macaques, and of heart and respiratory rate in stumptail monkeys of both sexes, before, during and after copulation. These data were fed into a multichannel recorder, along with a spoken record of behavioral changes. Males' heart and respiratory rates were raised during penile thrusting, reached a peak and then fell sharply after ejaculation. Uterine movements were similar during successive copulations. After uterine movements associated with penile thrusting prior to ejaculation a rise in contraction force occurred which lasted about 15 seconds. It is in this period, if ever, that a climax face was displayed by the female. The female's look-back and reach-back behaviors were not linked to either the pattern of uterine contractions or the occurrence of the climax face.

Animals↗
PubMed1987

Disruption of ejaculates by male copulation in deer mice (Peromyscus maniculatus).

Six experiments were conducted to analyze possible disruption of sperm transport occurring when one male deer mouse copulates soon after another male ejaculates. When a second male mated soon after the first, females had significantly fewer uterine sperm 1 hr later than when a delay of 7 or 15 min was imposed between males. However, it was impossible to detect any effect of such disruption on pregnancy initiation. Similarly, artificial stimulation soon after an ejaculation was ineffective in disrupting pregnancy initiation. No effect of a rapid resumption of copulation could be detected on litter composition in a sperm competition situation. Although it is clear, from these and other data, that the phenomenon of ejaculate disruption occurs in deer mice, technical difficulties may interfere with experimental analysis.

Animals↗
PubMed1988

GABAergic regulation of penile reflexes and copulation in rats.

In three experiments we investigated the role of the GABAergic system in regulating penile reflexes and copulation in rats. All males had the suspensory ligament of the penis removed 3 weeks before the experiments, thereby permitting the novel observation of penile body erections in addition to penile glans responses. In Experiments 1 and 2, rats were assigned to one of the following treatment groups: control (saline-injected); baclofen, a GABA-B receptor agonist (1 or 2 mg/kg); THIP, a GABA-A receptor agonist (5 mg/kg); or (+)bicuculline, a GABA-A receptor antagonist (0.25 mg/kg). Penile reflex tests began 20 min after SC injection. Baclofen treatment decreased the number of males responding with glans erections within the 30 min latency limit, and significantly reduced the number of glans erections displayed, in a dose-dependent manner. These results indicate that activation of GABA-B receptors inhibits penile reflexes outside the context of copulation (ex copula). Rats treated with baclofen also had a dose-dependent reduction in the ratio of clusters of glans erections to penile body erections, and a significant increase in the number of penile body erections observed prior to the first glans erection. These findings suggest that baclofen inhibited the mechanisms mediating penile glans responses more than those mediating penile body erections. Bicuculline was without effect in both experiments; THIP significantly increased erections in Experiment 2 but had no reliable effect in Experiment 1. Because baclofen inhibited penile responses in ex copula tests, Experiment 3 was designed to assess the effects of the same dosages of this agent on male copulatory behavior.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1977

5-hydroxytryptamine depletion with para-chlorophenylalanine: effects on eating, drinking, irritability, muricide, and copulation.

Forty-four male rats were tested for eating, drinking, irritability, and copulation before and after intraperitonial para-chlorophenylalanine (PCPA) or control injections. Eleven of these rats were tested for muricide before and after PCPA injections (Group 1), while 18 others were tested only after PCPA injections (Groups 2). Group 1 rats received four 350 mg/kg PCPA injections spaced 6 days apart and showed hyperdipsia, weight loss, and a 24% increase in muricide. Group 2 rats received five daily 100 mg/kg PCPA injections repeated 11 days later and showed hyperdipsia and weight loss; in addition, 78% of them killed mice. Neither group showed significant changes in copulation. At the end of the experiment, t6 rats from Group 2 that were irritable and killed mice were injected intraperitonially with 5-hydroxytryptophan (80 mg/kg). Five of these rats lost their irritability and four stopped killing. The various behavioral changes were not corrleated significantly either with each other or with the degree of 5-hydroxytryptamine depletion. This tentatively suggests that PCPA may produce its effects on behavior by other means in addition to 5-hydroxytryptamine depletion.

Aggression↗
PubMed1991

The ejaculatory reflex in copulating rats: normal bulbospongiosus activity without apparent urethral stimulation.

Electromyographic activity was recorded from the bulbospongiosus muscles of intact, copulating male rats to test the hypothesis that urethral stimulation contributes to the ejaculatory reflex. Neither urethral anesthetization with lidocaine nor prevention of emission with guanethidine affected the rhythmic contraction of the bulbospongiosus muscle during the ejaculatory pattern. Urethral stimulation by the ejaculate apparently does not contribute to the regulation of the striated-muscle components of ejaculation-related reflexes in copulating male rats.

Animals↗