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Results for “Copulation”

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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↗

PubMed1994

Preoptic and subthalamic connections with the caudal brainstem are important for copulation in the male rat.

Bilateral lesions of either the medial preoptic area/anterior hypothalamus (MPAH) or a subthalamic region that includes the caudal zona incerta eliminate copulation in male rats. Pathways connecting the MPAH and subthalamus with the caudal brainstem may help regulate sexual behavior. Experiment 1 showed that bilateral coronal transections of the pontine tegmentum reduce mating and that the combination of a unilateral tegmental cut with a contralateral excitotoxin lesion of either the MPAH (Experiment 2) or subthalamus (Experiment 3) virtually eliminates copulation. Asymmetric bilateral damage appears to eliminate mating through a bilateral effect common to the transection and the lesion--the destruction of connections linking the MPAH and subthalamus with the caudal brainstem. These results indicate that preoptic and subthalamic connections with the caudal brainstem are important for copulation in the male rat.

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↗

PubMed2000

Drosophila female sexual behavior induced by sterile males showing copulation complementation.

Females of most animal species are usually inseminated by more than one male, which allows sperm from different males to compete for fertilization. To prevent invasion of sperm from other males, Drosophila males elicit a rejection behavior in their mates after copulation. Using paired mutant males that, for the lack of accessory glands, are sterile, we show that this rejection behavior is induced exclusively by the secreted accessory gland products transferred to the female during copulation. Moreover, the activities of sperm and accessory gland products are complementary and interdependent: both sperm fertility and rejection behavior depend on accessory gland products whose prolonged activities, in turn, require the presence of sperm. Fertility of sperm from paired males can be restored by accessory gland products of spermless males in "copulation complementation" experiments. Our observations may have important implications for the role of sexual behavior in evolution and for the treatment of male sexual dysfunction in humans.

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↗

PubMed2000

The influence of male and female body size on copulation duration and fecundity in Drosophila melanogaster.

We studied two components of the mating system, copulation duration and early fecundity, in relation to body size in Drosophila melanogaster. Body size variation was created experimentally by varying the degree of crowding (starvation) among larvae from an inbred strain, keeping the genetics and temperature as constant as possible. Hence, in contrast to most previous studies, where genetic and environmental variation have been confounded, we aimed at investigating how much pure phenotypic variation could influence copulation duration and early fecundity. It is shown that copulation duration and fecundity both strongly dependent on female body size, but either not or much less so on male body size. Small females mate faster than medium or large females and small females have the lowest fecundity. Among males, medium-size males are more fecund than smaller or larger males, resulting in stabilising selection for intermediate male size. These results are in contrast with previous findings.

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↗

PubMed1982

Role of striated penile muscles in penile reflexes, copulation, and induction of pregnancy in the rat.

In 4 experiments, various striated penile muscles of the rat were excised. Without the ischiocavernosus (IC) muscles no dorsiflexions ('flips') of the glans penis occurred during ex copula reflex tests, but erections were unaffected. In attempted copulation, males lacking the IC muscles rarely gained intromission, apparently because dorsiflexion of the glans penis is necessary for penetration of the vagina. Nonetheless some males lacking the IC muscles displayed the gross motor pattern of intromission and ejaculated, but rarely within the vagina. Males lacking the bulbocavernosus (BC) and levator ani (LA) muscles were incapable of developing intense erections ('cups') in ex copula tests, but they did have lesser erections, probably due to vascular action. Males with excised BC and LA muscles displayed normal copulatory behaviour, including intromission and intravaginal ejaculation, but only 1/15 females mated to these males became pregnant. The infertility of the males was attributed in part to their inability to form the penile cup, which caused them to withdraw a larger portion of the seminal plug from the vagina and, presumably, prevented the plug from being tightly lodged against the cervix. In male rats copulation apparently requires co-ordination of the penile vasculature with the contraction of separate groups of striated penile muscles, each having a distinct contribution to the integrated pattern of copulation and, ultimately, to the male's fertility.

Animals↗

PubMed1996

Relaxin in peripheral plasma of boars during development, copulation, after administration of hCG and after castration.

Seventy-two Yorkshire boars were used in five experiments to evaluate the temporal changes in relaxin concentrations in peripheral blood plasma during prepubertal development, copulation, after castration and after treatment with hCG. High concentrations of relaxin (484 +/- 27 pg ml-1) were detected at 11 weeks of age but there was no positive correlation with testicular development. Relaxin concentrations fluctuated in mature boars but the results do not suggest a diurnal rhythm, although there is the possibility of pulsatile secretion. A decrease (P < 0.05) in circulating relaxin was observed before and immediately after copulation. Castration of boars at 90, 115, 160 and 200 days of age did not significantly decrease relaxin concentrations within 48 h. Administration of hCG significantly depressed relaxin secretion at 90 days of age but not at 160 days of age. These studies suggest a non-gonadal source of boar relaxin that is not correlated with testicular growth or testosterone concentrations, is modulated by copulation and by hCG but only at specific stages of development.

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↗

PubMed1994

Single- and multilocus DNA fingerprinting of communally breeding pukeko: do copulations or dominance ensure reproductive success?

In behavioral and ecological studies the "function" of dominance hierarchies is thought to be related to reproductive success. In particular, dominant males are regarded as likely to gain a reproductive advantage due to enhanced "access" to females. We compare the dominance status of adults with the frequency of copulations and the patterns of parentage in communally breeding pukeko or purple swamphen (Porphyrio porphyrio melanotus). This avian species has an unusual social system, often breeding in polygynandrous groups in which there is a strong dominance hierarchy. Typically, during the breeding season, there is considerable sexual activity, with heterosexual and homosexual copulations between adults being commonplace. Hae III-digested DNA from individuals belonging to breeding groups was hybridized to the minisatellite DNA probe YNH24, revealing putative single-locus profiles, while hybridization of the same DNA to the minisatellite probes pV47-2, 3'HVR, and per revealed typical multilocus profiles. The numbers of unattributable restriction fragments allowed the maternity and paternity of all individuals to be conclusively determined, despite high levels of band sharing among individuals within breeding groups. These close genetic similarities are a likely consequence of strong philopatry and inbreeding. We report instances of males which are high on the dominance hierarchy but have only a limited reproductive output in comparison with others and males which are subordinate but achieve a significant proportion of fertilizations. Generally these data reveal no consistent relationship between dominance, the frequency of copulations, and parentage among males. We conclude that pukeko highlight some difficulties with conventional explanations for the "function" of dominance.

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).

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