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PubMed1997

Mating-induced expression of c-fos in the male Syrian hamster brain: role of experience, pheromones, and ejaculations.

This study was designed to investigate the effects of pheromonal cues and specific behaviors within the male copulatory sequence on c-fos expression in the medial nucleus of the amygdala (Me), the bed nucleus of the stria terminalis (BNST), and the medial preoptic area (MPOA) of the Syrian hamster brain. Sexually experienced male hamsters were placed into clean testing arenas and were either: 1) left alone as handled controls; 2) exposed to female hamster vaginal secretion (FHVS) on cotton swabs; or mated to various end points of copulation with a sexually receptive female: 3) five intromissions, 4) one ejaculation, 5) five ejaculations, or 6) long intromissions, A seventh group of sexually naive control males 7) was left alone in the arena. The brains of these males were compared to those of the sexually experienced controls to determine whether exposure to cues associated with prior sexual experience could alter c-fos expression. In males exposed only to FHVS, Fos immunoreactivity (Fos-ir) increased within the posterodorsal Me, the anterodorsal part of the posteromedial BNST, and the magnocellular medial preoptic nucleus (MPNmag). Following one ejaculation, Fos-ir increased within the caudal posterodorsal Me, the dorsolateral MPOA, and the paraventricular nucleus of the hypothalamus. After multiple ejaculations, additional labeling was observed within the posteroventral part of the posteromedial BNST, the medial preoptic nucleus (MPN), the central tegmental field, and in cell clusters of the caudal posterodorsal Me and rostral posteromedial BNST. Fos-ir also increased within the posterodorsal Me, MPN, and MPNmag in sexually experienced control males exposed to the empty test chamber compared to sexually naive males exposed to an identical chamber. These results demonstrate that the mating-induced pattern of neuronal activation in sexually experienced males is dependent upon multiple factors, including prior sexual experience in the testing environment, investigation of FHVS, and the number of ejaculations achieved.

Amygdala↗
PubMed1998

Changes in the activity budget of cycling female chimpanzees.

This study is a preliminary report on the time allocated to various activities by female wild chimpanzees (Pan troglodytes schweinfurthii) during their sexual cycle. Cycling females with maximal tumescence (estrous females) tended to spend more time moving than cycling females with quiescent sexual skin (anestrous females). Although there was no statistically significant decrease in any specific activity that corresponded to the increase in time spent moving, feeding time did decrease in four of the five females. The frequency of approach by females toward males and the frequency of approach by males toward females significantly increased when females were in estrus. Direct aggression by males occurred more frequently toward estrous females than toward anestrous females. The copulation frequency and the frequency of approach to males was not significantly correlated with the increase in time spent moving. There was a high but not significant correlation between the time spent moving and the frequency of direct aggression by males toward females. Mating effort, feeding competition, male aggression, and other possible reasons that might explain the increase in moving time are discussed.

Aggression↗
PubMed2002

Multiple sirehood in free-ranging twin rhesus macaques (Macaca mulatta).

Rhesus macaque females regularly copulate with a number of partners, and produce a single offspring per reproductive cycle in over 99% of cases. We used genotyping of 10 STR markers to determine paternity in the Cayo Santiago population of rhesus macaques. About 1,500 monkeys have been analyzed to date, with their marker genotypes entered into a computerized database. These data enable us to report the first documented case in any cercopithecine nonhuman primate species of the production of twin offspring sired by different males.

Animals↗
PubMed1992

The sex-peptide.

Injection of a peptide of 36 amino acids into virgin Drosophila females changes their reproductive properties drastically: males are rejected and egg laying is increased. The neuronal and physiological properties of the virgin state are replaced by a new pattern of behavior and stimulation of egg production and deposition. Under natural conditions, the peptide is synthesized by the male and transferred into the female during copulation. The sex-peptide, therefore, can be considered as a pheromone. In this review, I shall limit my discussion to Drosophila melanogaster.

Amino Acid Sequence↗
PubMed1982

Effects of postweaning rearing condition on recovery of copulatory behavior from lesions of the medial preoptic area in rats.

Bilateral lesions of the medial preoptic area (MPOA)-anterior hypothalamus of adult male rats markedly disrupt male copulatory behavior. In contrast, more group--reared then isolated male rats receiving bilateral MPOA lesions as juveniles copulated to ejaculation as adults. The present experiment was designed to analyze the role of rearing condition in promoting copulatory recovery from MPOA lesions in juvenile male rats. Juvenile male rats were given bilateral MPOA lesions or a sham operation and reared in isolation without handling, in isolation with daily handling, across a perforated Plexiglas divider from a male peer, or together with a male peer (social). Socially reared and handled males, but not isolated and divided males, with MPOA lesions showed evidence of copulatory recovery (combined socially reared and handled males vs combined isolated and divided males). These results support previous findings that postweaning rearing condition can affect copulatory recovery following juvenile MPOA lesions, but indicate that play experiences involving physical contact with peers are not necessary for such recovery to occur.

Animals↗
PubMed2002

Sperm storage and motility in the ovary of the marine sculpin Alcichthys alcicornis (Teleostei: Scorpaeniformes), with internal gametic association.

Elkhorn sculpin, Alcichthys alcicornis, is a marine teleost with a unique reproductive mode called "internal gametic association," in which sperm introduced into the ovary by copulation enter the micropylar canal of ovulated eggs in the ovarian cavity, but actual sperm-egg fusion does not occur until the eggs have been released into sea water. It is also known that this fish is a multiple spawner, which spawns at intervals of a few days for one month, and the sperm introduced into the ovary at the beginning of the spawning season retain their fertilizability for the entire period. To clarify how the fertilizability of sperm is maintained internally, the ultrastructure of sperm, the morphological characteristics related to sperm storage in the ovary, and the characteristics of sperm motility were investigated. Mature sperm generally have the normal form of teleost sperm, devoid of acrosomal structures. However, it was found that the midpiece is comparatively elongated and has a compact aggregation of many small-size mitochondria. The intraovarian sperm remained floating in the ovarian fluid throughout the spawning season. The sperm showed high motility in isotonic and weak alkaline solution, containing sodium ions, which was similar to the ovarian fluid of this fish. Sperm continued to move in artificial ovarian fluid for 7-14 days. Considering these results together, it is thought that the intraovarian sperm move throughout the spawning season due to the plentiful energy generated by the many mitochondria.

Animals↗
PubMed1975

The effects of castration and androgen replacement on song, courtship, and aggression in zebra finches (Poephila guttata).

Castration of adult male zebra finches (Poephila guttata, Estrildidae) reduces their singing rate and the tempo of song, but castrates continue to sing song identical in form to preoperative song. Injection or implantation of testosterone propionate (TP) but not of vehicle alone reverses the changes produced by castration. Castration or partial castration also reduces the frequency of courtship, copulation, and aggression. Androgen (TP) replacement reverses these changes, but control injections do not. The persistence of song after castration contrasts with the abolition of song by castration in other birds, and this may be related to the natural history of zebra finches.

Aggression↗
PubMed1976

The role of the copulatory plug in reproduction of the guinea pig.

Two methods of artificial insemination and removal of copulatory plugs were used to investigate the role of the plug in the guinea pig. In addition, the effectiveness of the copulatory plug in blocking the passage of spermatozoa from the second mating was tested in albino females, where coat color was used as a genetic marker. Thirteen female guinea pigs that were either in proestrus, estrus, or metestrus, and inseminated with freshly collected copulatory plugs containing living spermatozoa, did not conceive. In a group of six females from which the copulatory plus was immediately removed, five conceived. Of nine estrous females artificially inseminated, five conceived. In five albino females, copulatory plugs from albino males completely blocked spermatozoa deposited by colored males, and 20 offspring, all albino were born. In a second group of four albino females where the plugs of albino males were removed prior to copulation with colored males, resulting litters were sired by either male or a combination of both males.

Animals↗
PubMed2003

Application of artificial insemination technique to eupyrene and/or apyrene sperm in Bombyx mori.

The silkworm, Bombyx mori, has a dimorphic sperm system. The eupyrene sperm is the sperm to fertilize eggs and the apyrene sperm plays a crucial role for assisting fertilization. Heat-treated (33 degrees C for 96h) Daizo (DH) males, one of the strains in the silkworm, produce only eupyrene sperm, while in triploid males only apyrene sperm are functional. Though both types of males are found to be sterile, double copulation of the two males with a single female greatly increases fertility. Here we examined the fertilizing ability of eupyrene and apyrene sperm by means of an artificial insemination technique previously established in B. mori. Neither the eupyrene sperm collected from DH males, nor the apyrene sperm from triploid males have the ability to fertilize eggs. Artificial insemination with the mixture of eupyrene and apyrene sperm leveled up the frequency of fertilized eggs to more than 80%. When cryopreserved DH sperm (eupyrene sperm) were subjected to the same experiment, more than 95% fertilized eggs were obtained. These results confirmed that apyrene sperm play an important and indispensable role in fertilization in B. mori. Separate collection of functional eupyrene sperm and functional apyrene sperm and success of fertilization by means of the artificial insemination technique are applicable for further studies to elucidate the function of apyrene sperm.

Animals↗
PubMed2007

Structure of the vector tissue in piscicolid leeches (Annelida, Hirudinea, Rhynchobdellida, Piscicolidae).

Hypodermic insemination occurs in piscicolid leeches (Hirudinea, Rhynchobdellida, Piscicolidae). The spermatophore is implanted in a specialized region of the leech body, the copulatory area. Just beneath the copulatory area, there is a specialized connective tissue (vector tissue) that is considered to guide the sperm toward the ovaries. In this study, we show that the vector tissue in the four species of the genus Piscicola is composed of a mass of cells located directly beneath the copulatory area, and two thin strands extend toward the ovaries. The ultrastructure of the vector tissue has been described for the first time. Four cell types were identified, constructing the vector tissue. The envelope of this tissue is made up of extracellular fibrous matrix and two types of cells: vesicular and flat envelope cells, which are embedded within the matrix. The rest of the tissue is formed of granular and plasmatic cells. Both of these last cell types have prominent cytoplasmic projections, filled with a filamentous material. However, only granular cells have numerous small electron-dense granules in their cytoplasm. The vector tissue was described prior, during and following copulation. Sperm passes within free spaces between the granular and plasmatic cells. Characteristic vector tissue cells also occur within the ovary wall and inside the ovary lumen. This supports earlier data, which postulated that the vector tissue appears to be an outgrowth of the ovary wall.

Animals↗
PubMed1985

The anatomy and functional morphology of the large hermaphroditic duct of three species of Aplysia, with special reference to the atrial gland.

The anatomy and functional morphology of the large hermaphroditic duct of three species of gastropod mollusc (Aplysia californica, A. dactylomela, and A. brasiliana) were examined. Each duct is composed of two parallel compartments, the red hemiduct (RHD) and the white hemiduct (WHD), which are distinguishable from the outside of the duct. Four secretory regions, all exocrine in morphology, are recognizable: the RHD secretory epithelium, the atrial gland (or atrial gland-like epithelium), the WHD secretory epithelium, and the accessory gland of the copulatory duct (AGCD). Of these regions, only the atrial gland (or atrial gland-like epithelium) contains egglaying activity and only the atrial gland (or atrial gland-like epithelium) is immunocytochemically labeled by serum antibodies generated against low molecular weight A. californica atrial gland peptides. The RHD is the functional oviduct: the egg cordon passes through a channel lined by the RHD secretory epithelium and bordered by the atrial gland (or atrial gland-like epithelium); the eggs are separated from both the WHD secretory epithelium and the AGCD by internal folds of the duct. The WHD is the functional copulatory duct: the penis, exogenous sperm, and endogenous sperm pass directly by the AGCD and in close proximity to the WHD secretory epithelium; they are separated from both the RHD secretory epithelium and the atrial gland (or atrial gland-like epithelium) by internal folds. The atrial gland (or atrial gland-like epithelium) is thus not likely to have a prostatic function or to be directly stimulated by the penis during copulation; it may play a role in oviductal function.

Animals↗
PubMed1988

Effects of delayed mating on preimplantation embryos in spontaneously ovulated mice.

The effects of delayed mating on mouse preimplantation embryos (78 +/- 1 hours) were studied by setting up different mating periods in relation to the estimated time of spontaneous ovulation. Copulation occurred even in the late morning and early afternoon after the night of spontaneous ovulation. However, females mated in the early afternoon had no viable embryos at the time of laparotomy. Although embryonic development was not affected in the groups mated 6 or 10 hours after estimated ovulation, the percentage of degenerated embryos was increased in these groups. These results suggest that prolonged intervals between the estimated time of ovulation and mating have some deleterious effects on preimplantation embryos.

Animals↗
PubMed2003

Genetic basis of male sexual behavior.

Male sexual behavior is increasingly the focus of genetic study in a variety of animals. Genetic analysis in the soil roundworm Caenorhabditis elegans and the fruit fly Drosophila melanogaster has lead to identification of genes and circuits that govern behaviors ranging from motivation and mate-searching to courtship and copulation. Some worm and fly genes have counterparts with related functions in higher animals and many more such correspondences can be expected. Analysis of mutations in mammals can potentially lead to insights into such issues as monogamous versus promiscuous sexual behavior and sexual orientation. Genetic analysis of sexual behavior has implications for understanding how the nervous system generates and controls a complex behavior. It can also help us to gain an appreciation of how behavior is encoded by genes and their regulatory sequences.

Animals↗
PubMed1993

Sexual activity and plasma levels of sex steroids in the aspic viper Vipera aspis L. (Reptilia, Viperidae).

Reproductive behavior and associated sexual activity was studied in individual male and female Vipera aspis over a 3-year period in western France in an attempt to correlate mating behavior with blood levels of gonadal sex steroids. Males had higher average levels of both testosterone (T) and 5 alpha-dihydrotestosterone (DHT) than females. Levels of progesterone (P) did not differ significantly between the two sexes but estradiol-17 beta (E2) concentrations were significantly higher in females during the season of mating. Spring mating behavior and copulation in males was associated with significantly increased levels of T and DHT, compared with postmating males; and a similar, but not significant trend, was evident with autumnal mating. The only statistically significant hormonal difference detected in males showing no sexual activity in autumn, was an elevated level of E2 at 0.52 +/- 0.20 ng/ml compared with 0.09 +/- 0.03 ng/ml in spring-breeding males (P = 0.05). Estrus in females is associated with increased levels of all four steroids but significant only for E2 and DHT. Levels of P were significantly reduced in females displaying seasonal anestrous in the spring immediately following reproduction. Females not displaying estrus in either spring or autumn had significantly lower plasma DHT and E2. Although mating behavior in males is associated statistically with elevated levels of T and DHT, a tight correlation is not obvious at the individual level, suggesting that increased concentrations of androgens are a necessary, but not sufficient, condition for mating. The data from V. aspis suggest that, as in a number of other reptilian species, high circulating levels of androgens function to "condition" or "organize" sexual behavior in males which may be displayed at some later time, well after actual levels have fallen, thus engendering the impression that reproductive behavior may be temporally dissociated from essential hormonal stimuli.

Animals↗
PubMed1993

Neonatal testicular suppression with a GnRH agonist in rhesus monkeys: effects on adult endocrine function and behavior.

Male rhesus monkeys secrete adult levels of androgen for 3 months postnatally. The role of this neonatal testicular secretion in sexual development was investigated by suppressing luteinizing hormone (LH) and testosterone (T) in neonatal male rhesus (n = 6) by administering a gonadotropin-releasing hormone agonist (Ag) for the first 4 months of postnatal life. Controls (n = 4) received vehicle. Six years later, endocrine function and sexual behavior were examined with ovariectomized females (n = 6) receiving periodic estradiol (E2) treatment during the breeding and nonbreeding seasons. During the breeding season, there were no differences between Ag-treated and control males in levels of LH and T or in frequency of copulatory behavior. However, Ag-treated males masturbated less frequently than controls when the females were not on E2. During the nonbreeding season, Ag-treated males had lower T levels than controls when the females were not receiving E2 and copulated less when the females received E2, even though T levels were comparable. During both E2 and non-E2 treatments, Ag-treated males secreted less T per unit of LH than controls. Neonatal Ag treatment had no effect on social rank. These data demonstrate that neonatal testicular suppression, or the Ag treatment itself, altered systems regulating sexual motivation and neuroendocrine control of these males and suggest that the early neonatal period in male rhesus monkeys is another point when the developing central nervous system is sensitive to the organizing actions of androgens.

Animals↗
PubMed1997

Central administration of chicken gonadotropin-releasing hormone-II enhances courtship behavior in a female sparrow.

Like most vertebrates, birds have two forms of gonadotropin-releasing hormone (GnRH). Chicken GnRH-I (cGnRH-I) is released at the median eminence to elicit gonadotropin release; chicken GnRH-II (cGnRH-II) is thought to be non-hypophysiotropic and its function is unclear. Both forms are hypothesized to act as neurotransmitters in the control of reproductive behavior. In the present study, we implanted chronic cannulae aimed at the third ventricle in female white-crowned sparrows (Zonotrichia leucophrys gambelii) to test the effects of both forms of GnRH on copulation solicitation, a female courtship behavior. This behavior can be elicited in captive, estrogen-primed females by playing a recording of male song. We quantified the behavioral response to recorded song 30, 60, and 90 min after intracerebroventricular infusion of cGnRH-I, -II, or saline. cGnRH-II, but not cGnRH-I, increased solicitation behavior compared with saline 30 min after infusion. Under control conditions, responses to the playback diminish from the 30-min to the 90-min time point. Responses after cGnRH-II infusion followed a similar pattern, whereas after cGnRH-I, there was no significant response decrement. cGnRH-I appears to maintain the level of solicitation seen at 30 min after infusion. Our results suggest a behavioral role for cGnRH-II that may be independent of cGnRH-I.

Animals↗
PubMed1997

Hormonal activation of the striatum and the nucleus accumbens modulates paced mating behavior in the female rat.

Sexual behavior in the female rat has both sensorimotor and motivational components, which can be distinguished when the female rat is able to pace the rate of copulation. The experiments reported were conducted to determine whether estrogen application to the striatum and/or nucleus accumbens affects pacing behavior. In order to induce sexual receptivity, ovariectomized rats received sequential bilateral implants of 17beta-estradiol followed by progesterone into the ventromedial nucleus of the hypothalamus. Then, bilateral implants of 17beta-estradiol or cholesterol were administered into either the dorsolateral striatum or the nucleus accumbens. Pacing behavior was tested 4 hr later. It was found that intrastriatal application of estradiol significantly facilitated the percent exits exhibited after copulatory contact, whereas application of estradiol in the nucleus accumbens affected the return latency. To determine whether estrogen in the striatum or nucleus accumbens normally plays a role in pacing behavior, intrastriatal or intra-accumbens implants containing the steroidal antiestrogen ICI 182,780 or vehicle were given to ovariectomized female rats treated systemically with estrogen and progesterone. The antiestrogen treatment decreased the percent exits when delivered to the striatum and affected return latency when delivered to the nucleus accumbens. The results indicate that estrogen acts directly in the striatum and in the nucleus accumbens to differentially modulate specific components of pacing behavior.

Animals↗
PubMed1999

Appetitive and consummatory sexual behaviors of female rats in bilevel chambers. I. A correlational and factor analysis and the effects of ovarian hormones.

This study investigated measures of sexual behavior displayed by female rats in bilevel chambers, the statistical relationships among the measures, and their dependency on hormone priming. Normative data from a standard 35-min test of sexual behavior were gathered from 82 fully primed sexually experienced Long-Evans females and subjected to multiple correlational and factor analyses. Several consummatory measures of copulation were related significantly, whereas appetitive level changing was statistically independent of consummatory measures. Factor analyses were conducted using orthogonal rotations of correlational matrices derived either from (a) measures of female behavior alone or (b) measures of female and male behavior together. The first analysis revealed five factors that accounted for 84% of the intersubject variance: Receptivity, Pacing, Appetitive Level Changing, Lordosis Reflex, and Solicitation. The second factor analysis with male data included revealed seven factors that accounted for 95% of the intersubject variance: Pacing, Copulatory Rate, Mount Count, Receptivity, Appetitive Level Changing, Solicitation, and Lordosis Reflex. Subsequently, subsets of these females were maintained on different steroid priming regimens (oil, low estrogen, high estrogen, high estrogen and progesterone) prior to a standard test of sexual behavior. Although the expression of all sexual behaviors required estrogen priming, appetitive level changing, solicitation, and pacing required progesterone for their full expression. Finally, appetitive level changing developed following hormone treatment alone, regardless of whether the females received access to sexually active males, inactive castrated males, or other females. Use of bilevel chambers allows complex patterns of sexual behavior to be observed in female rats and may thus facilitate the identification of neurochemical or endocrine mechanisms associated with different aspects of female sexual motivation and performance.

Animals↗