Sexual Behavior, Animal: Sexual activities of animals.Cannibalism: Eating other individuals of one's own species.Ejaculation: The emission of SEMEN to the exterior, resulting from the contraction of muscles surrounding the male internal urogenital ducts.Insemination: The deposit of SEMEN or SPERMATOZOA into the VAGINA to facilitate FERTILIZATION.Genitalia, Male: The male reproductive organs. They are divided into the external organs (PENIS; SCROTUM;and URETHRA) and the internal organs (TESTIS; EPIDIDYMIS; VAS DEFERENS; SEMINAL VESICLES; EJACULATORY DUCTS; PROSTATE; and BULBOURETHRAL GLANDS).GibraltarSperm Transport: Passive or active movement of SPERMATOZOA from the testicular SEMINIFEROUS TUBULES through the male reproductive tract as well as within the female reproductive tract.Mating Preference, Animal: The selection or choice of sexual partner in animals. Often this reproductive preference is based on traits in the potential mate, such as coloration, size, or behavioral boldness. If the chosen ones are genetically different from the rejected ones, then NATURAL SELECTION is occurring.Reproduction: The total process by which organisms produce offspring. (Stedman, 25th ed)Preoptic Area: Region of hypothalamus between the ANTERIOR COMMISSURE and OPTIC CHIASM.Fertility: The capacity to conceive or to induce conception. It may refer to either the male or female.Competitive Behavior: The direct struggle between individuals for environmental necessities or for a common goal.Pregnanediol: An inactive metabolite of PROGESTERONE by reduction at C5, C3, and C20 position. Pregnanediol has two hydroxyl groups, at 3-alpha and 20-alpha. It is detectable in URINE after OVULATION and is found in great quantities in the pregnancy urine.Sex Attractants: Pheromones that elicit sexual attraction or mating behavior usually in members of the opposite sex in the same species.Genitalia, Female: The female reproductive organs. The external organs include the VULVA; BARTHOLIN'S GLANDS; and CLITORIS. The internal organs include the VAGINA; UTERUS; OVARY; and FALLOPIAN TUBES.Spiders: Arthropods of the class ARACHNIDA, order Araneae. Except for mites and ticks, spiders constitute the largest order of arachnids, with approximately 37,000 species having been described. The majority of spiders are harmless, although some species can be regarded as moderately harmful since their bites can lead to quite severe local symptoms. (From Barnes, Invertebrate Zoology, 5th ed, p508; Smith, Insects and Other Arthropods of Medical Importance, 1973, pp424-430)Panstrongylus: A genus of cone-nosed bugs of the subfamily TRIATOMINAE. Its species are vectors of TRYPANOSOMA CRUZI.Tephritidae: A large family of fruit flies in the order DIPTERA, comprising over 4,500 species in about 100 genera. They have patterned wings and brightly colored bodies and are found predominantly in the tropical latitudes.Courtship: Activities designed to attract the attention or favors of another.Consummatory Behavior: An act which constitutes the termination of a given instinctive behavior pattern or sequence.Camelids, New World: Ruminant mammals of South America. They are related to camels.Papio hamadryas: A species of baboon in the family CERCOPITHECIDAE, which has a well-studied trilevel social structure consisting of troops, bands, and clans.Penis: The external reproductive organ of males. It is composed of a mass of erectile tissue enclosed in three cylindrical fibrous compartments. Two of the three compartments, the corpus cavernosa, are placed side-by-side along the upper part of the organ. The third compartment below, the corpus spongiosum, houses the urethra.Paternity: Establishing the father relationship of a man and a child.Oviposition: The process of laying or shedding fully developed eggs (OVA) from the female body. The term is usually used for certain INSECTS or FISHES with an organ called ovipositor where eggs are stored or deposited before expulsion from the body.Spermatozoa: Mature male germ cells derived from SPERMATIDS. As spermatids move toward the lumen of the SEMINIFEROUS TUBULES, they undergo extensive structural changes including the loss of cytoplasm, condensation of CHROMATIN into the SPERM HEAD, formation of the ACROSOME cap, the SPERM MIDPIECE and the SPERM TAIL that provides motility.Weevils: BEETLES in the family Curculionidae and the largest family in the order COLEOPTERA. They have a markedly convex shape and many are considered pests.Vocalization, Animal: Sounds used in animal communication.Bedbugs: Bugs of the family CIMICIDAE, genus Cimex. They are flattened, oval, reddish insects which inhabit houses, wallpaper, furniture, and beds. C. lectularius, of temperate regions, is the common bedbug that attacks humans and is frequently a serious pest in houses, hotels, barracks, and other living quarters. Experiments have shown that bedbugs can transmit a variety of diseases, but they are not normal vectors under natural conditions. (From Dorland, 27th ed; Borror, et al., An Introduction to the Study of Insects, 4th ed, p272)Gryllidae: The family Gryllidae consists of the common house cricket, Acheta domesticus, which is used in neurological and physiological studies. Other genera include Gryllotalpa (mole cricket); Gryllus (field cricket); and Oecanthus (tree cricket).Chiroptera: Order of mammals whose members are adapted for flight. It includes bats, flying foxes, and fruit bats.Poecilia: A genus of livebearing cyprinodont fish comprising the guppy and molly. Some species are virtually all female and depend on sperm from other species to stimulate egg development. Poecilia is used in carcinogenicity studies as well as neurologic and physiologic research.Triatominae: A subfamily of assassin bugs (REDUVIIDAE) that are obligate blood-suckers of vertebrates. Included are the genera TRIATOMA; RHODNIUS; and PANSTRONGYLUS, which are vectors of TRYPANOSOMA CRUZI, the agent of CHAGAS DISEASE in humans.Pair Bond: In animals, the social relationship established between a male and female for reproduction. It may include raising of young.Sperm Count: A count of SPERM in the ejaculum, expressed as number per milliliter.Drosophila melanogaster: A species of fruit fly much used in genetics because of the large size of its chromosomes.Clitoris: An erectile structure homologous with the penis, situated beneath the anterior labial commissure, partially hidden between the anterior ends of the labia minora.Cloaca: A dilated cavity extended caudally from the hindgut. In adult birds, reptiles, amphibians, and many fishes but few mammals, cloaca is a common chamber into which the digestive, urinary and reproductive tracts discharge their contents. In most mammals, cloaca gives rise to LARGE INTESTINE; URINARY BLADDER; and GENITALIA.Cyprinodontiformes: An order of fish with eight families and numerous species of both egg-laying and livebearing fish. Families include Cyprinodontidae (egg-laying KILLIFISHES;), FUNDULIDAEl; (topminnows), Goodeidae (Mexican livebearers), Jenynsiidae (jenynsiids), Poeciliidae (livebearers), Profundulidae (Middle American killifishes), Aplocheilidae, and Rivulidae (rivulines). In the family Poeciliidae, the guppy and molly belong to the genus POECILIA.Beetles: INSECTS of the order Coleoptera, containing over 350,000 species in 150 families. They possess hard bodies and their mouthparts are adapted for chewing.Social Dominance: Social structure of a group as it relates to the relative social rank of dominance status of its members. (APA, Thesaurus of Psychological Index Terms, 8th ed.)Grooming: An animal's cleaning and caring for the body surface. This includes preening, the cleaning and oiling of feathers with the bill or of hair with the tongue.Sex Characteristics: Those characteristics that distinguish one SEX from the other. The primary sex characteristics are the OVARIES and TESTES and their related hormones. Secondary sex characteristics are those which are masculine or feminine but not directly related to reproduction.Passeriformes: A widely distributed order of perching BIRDS, including more than half of all bird species.Conflict (Psychology): The internal individual struggle resulting from incompatible or opposing needs, drives, or external and internal demands. In group interactions, competitive or opposing action of incompatibles: antagonistic state or action (as of divergent ideas, interests, or persons). (from Merriam-Webster's Collegiate Dictionary, 10th ed)Estrus: The period in the ESTROUS CYCLE associated with maximum sexual receptivity and fertility in non-primate female mammals.Disorders of Sex Development: In gonochoristic organisms, congenital conditions in which development of chromosomal, gonadal, or anatomical sex is atypical. Effects from exposure to abnormal levels of GONADAL HORMONES in the maternal environment, or disruption of the function of those hormones by ENDOCRINE DISRUPTORS are included.Semen: The thick, yellowish-white, viscid fluid secretion of male reproductive organs discharged upon ejaculation. In addition to reproductive organ secretions, it contains SPERMATOZOA and their nutrient plasma.Animal Structures: Organs and other anatomical structures of non-human vertebrate and invertebrate animals.Biological Evolution: The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.Genitalia: The external and internal organs related to reproduction.Sex Ratio: The number of males per 100 females.HydrocarbonsPupa: An inactive stage between the larval and adult stages in the life cycle of insects.Songbirds: PASSERIFORMES of the suborder, Oscines, in which the flexor tendons of the toes are separate, and the lower syrinx has 4 to 9 pairs of tensor muscles inserted at both ends of the tracheal half rings. They include many commonly recognized birds such as CROWS; FINCHES; robins; SPARROWS; and SWALLOWS.Longevity: The normal length of time of an organism's life.Orchiectomy: The surgical removal of one or both testicles.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Diptera: An order of the class Insecta. Wings, when present, number two and distinguish Diptera from other so-called flies, while the halteres, or reduced hindwings, separate Diptera from other insects with one pair of wings. The order includes the families Calliphoridae, Oestridae, Phoridae, SARCOPHAGIDAE, Scatophagidae, Sciaridae, SIMULIIDAE, Tabanidae, Therevidae, Trypetidae, CERATOPOGONIDAE; CHIRONOMIDAE; CULICIDAE; DROSOPHILIDAE; GLOSSINIDAE; MUSCIDAE; TEPHRITIDAE; and PSYCHODIDAE. The larval form of Diptera species are called maggots (see LARVA).Observation: The act of regarding attentively and studying facts and occurrences, gathering data through analyzing, measuring, and drawing conclusions, with the purpose of applying the observed information to theoretical assumptions. Observation as a scientific method in the acquisition of knowledge began in classical antiquity; in modern science and medicine its greatest application is facilitated by modern technology. Observation is one of the components of the research process.Body Size: The physical measurements of a body.Birds: Warm-blooded VERTEBRATES possessing FEATHERS and belonging to the class Aves.Ganglia, Invertebrate: Clusters of neuronal cell bodies in invertebrates. Invertebrate ganglia may also contain neuronal processes and non-neuronal supporting cells. Many invertebrate ganglia are favorable subjects for research because they have small numbers of functional neuronal types which can be identified from one animal to another.Testosterone: A potent androgenic steroid and major product secreted by the LEYDIG CELLS of the TESTIS. Its production is stimulated by LUTEINIZING HORMONE from the PITUITARY GLAND. In turn, testosterone exerts feedback control of the pituitary LH and FSH secretion. Depending on the tissues, testosterone can be further converted to DIHYDROTESTOSTERONE or ESTRADIOL.Insects: The class Insecta, in the phylum ARTHROPODA, whose members are characterized by division into three parts: head, thorax, and abdomen. They are the dominant group of animals on earth; several hundred thousand different kinds having been described. Three orders, HEMIPTERA; DIPTERA; and SIPHONAPTERA; are of medical interest in that they cause disease in humans and animals. (From Borror et al., An Introduction to the Study of Insects, 4th ed, p1)Behavior, Animal: The observable response an animal makes to any situation.Drosophila: A genus of small, two-winged flies containing approximately 900 described species. These organisms are the most extensively studied of all genera from the standpoint of genetics and cytology.Rats, Long-Evans: An outbred strain of rats developed in 1915 by crossing several Wistar Institute white females with a wild gray male. Inbred strains have been derived from this original outbred strain, including Long-Evans cinnamon rats (RATS, INBRED LEC) and Otsuka-Long-Evans-Tokushima Fatty rats (RATS, INBRED OLETF), which are models for Wilson's disease and non-insulin dependent diabetes mellitus, respectively.Social Behavior: Any behavior caused by or affecting another individual, usually of the same species.Vagina: The genital canal in the female, extending from the UTERUS to the VULVA. (Stedman, 25th ed)Luteinizing Hormone: A major gonadotropin secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Luteinizing hormone regulates steroid production by the interstitial cells of the TESTIS and the OVARY. The preovulatory LUTEINIZING HORMONE surge in females induces OVULATION, and subsequent LUTEINIZATION of the follicle. LUTEINIZING HORMONE consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the three pituitary glycoprotein hormones (TSH, LH and FSH), but the beta subunit is unique and confers its biological specificity.Aggression: Behavior which may be manifested by destructive and attacking action which is verbal or physical, by covert attitudes of hostility or by obstructionism.Macaca: A genus of the subfamily CERCOPITHECINAE, family CERCOPITHECIDAE, consisting of 16 species inhabiting forests of Africa, Asia, and the islands of Borneo, Philippines, and Celebes.Gonadal Steroid Hormones: Steroid hormones produced by the GONADS. They stimulate reproductive organs, germ cell maturation, and the secondary sex characteristics in the males and the females. The major sex steroid hormones include ESTRADIOL; PROGESTERONE; and TESTOSTERONE.Animals, Genetically Modified: ANIMALS whose GENOME has been altered by GENETIC ENGINEERING, or their offspring.Drosophila Proteins: Proteins that originate from insect species belonging to the genus DROSOPHILA. The proteins from the most intensely studied species of Drosophila, DROSOPHILA MELANOGASTER, are the subject of much interest in the area of MORPHOGENESIS and development.Ovary: The reproductive organ (GONADS) in female animals. In vertebrates, the ovary contains two functional parts: the OVARIAN FOLLICLE for the production of female germ cells (OOGENESIS); and the endocrine cells (GRANULOSA CELLS; THECA CELLS; and LUTEAL CELLS) for the production of ESTROGENS and PROGESTERONE.Microdialysis: A technique for measuring extracellular concentrations of substances in tissues, usually in vivo, by means of a small probe equipped with a semipermeable membrane. Substances may also be introduced into the extracellular space through the membrane.Genes, Insect: The functional hereditary units of INSECTS.Copulation: Sexual union of a male and a female in non-human species.Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.Selection, Genetic: Differential and non-random reproduction of different genotypes, operating to alter the gene frequencies within a population.Microinjections: The injection of very small amounts of fluid, often with the aid of a microscope and microsyringes.Seasons: Divisions of the year according to some regularly recurrent phenomena usually astronomical or climatic. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Population Density: Number of individuals in a population relative to space.Pregnancy, Animal: The process of bearing developing young (EMBRYOS or FETUSES) in utero in non-human mammals, beginning from FERTILIZATION to BIRTH.Testis: The male gonad containing two functional parts: the SEMINIFEROUS TUBULES for the production and transport of male germ cells (SPERMATOGENESIS) and the interstitial compartment containing LEYDIG CELLS that produce ANDROGENS.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Uterus: The hollow thick-walled muscular organ in the female PELVIS. It consists of the fundus (the body) which is the site of EMBRYO IMPLANTATION and FETAL DEVELOPMENT. Beyond the isthmus at the perineal end of fundus, is CERVIX UTERI (the neck) opening into VAGINA. Beyond the isthmi at the upper abdominal end of fundus, are the FALLOPIAN TUBES.Dopamine: One of the catecholamine NEUROTRANSMITTERS in the brain. It is derived from TYROSINE and is the precursor to NOREPINEPHRINE and EPINEPHRINE. Dopamine is a major transmitter in the extrapyramidal system of the brain, and important in regulating movement. A family of receptors (RECEPTORS, DOPAMINE) mediate its action.Extracellular Space: Interstitial space between cells, occupied by INTERSTITIAL FLUID as well as amorphous and fibrous substances. For organisms with a CELL WALL, the extracellular space includes everything outside of the CELL MEMBRANE including the PERIPLASM and the cell wall.Pituitary Gland: A small, unpaired gland situated in the SELLA TURCICA. It is connected to the HYPOTHALAMUS by a short stalk which is called the INFUNDIBULUM.Radioimmunoassay: Classic quantitative assay for detection of antigen-antibody reactions using a radioactively labeled substance (radioligand) either directly or indirectly to measure the binding of the unlabeled substance to a specific antibody or other receptor system. Non-immunogenic substances (e.g., haptens) can be measured if coupled to larger carrier proteins (e.g., bovine gamma-globulin or human serum albumin) capable of inducing antibody formation.Gonadotropin-Releasing Hormone: A decapeptide that stimulates the synthesis and secretion of both pituitary gonadotropins, LUTEINIZING HORMONE and FOLLICLE STIMULATING HORMONE. GnRH is produced by neurons in the septum PREOPTIC AREA of the HYPOTHALAMUS and released into the pituitary portal blood, leading to stimulation of GONADOTROPHS in the ANTERIOR PITUITARY GLAND.Progesterone: The major progestational steroid that is secreted primarily by the CORPUS LUTEUM and the PLACENTA. Progesterone acts on the UTERUS, the MAMMARY GLANDS and the BRAIN. It is required in EMBRYO IMPLANTATION; PREGNANCY maintenance, and the development of mammary tissue for MILK production. Progesterone, converted from PREGNENOLONE, also serves as an intermediate in the biosynthesis of GONADAL STEROID HORMONES and adrenal CORTICOSTEROIDS.Linear Models: Statistical models in which the value of a parameter for a given value of a factor is assumed to be equal to a + bx, where a and b are constants. The models predict a linear regression.Organ Size: The measurement of an organ in volume, mass, or heaviness.Estradiol: The 17-beta-isomer of estradiol, an aromatized C18 steroid with hydroxyl group at 3-beta- and 17-beta-position. Estradiol-17-beta is the most potent form of mammalian estrogenic steroids.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Genetic Variation: Genotypic differences observed among individuals in a population.Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.

Prolonged mating in prairie voles (Microtus ochrogaster) increases likelihood of ovulation and embryo number. (1/462)

Prairie voles are induced ovulators that mate frequently in brief bouts over a period of approximately 24 h. We examined 1) impact of mating duration on ovulation and embryo number, 2) incidence of fertilization, 3) temporal pattern of embryo development, 4) embryo progression through the reproductive tract over time, and 5) embryo development in culture. Mating was videotaped to determine first copulation, and the ovaries were examined and the reproductive tracts flushed at 6, 8, 10, 12, 16, 20, and 24 h and 2, 3, and 4 days after first copulation. The number of mature follicles and fresh corpora lutea and the number and developmental stage of embryos were quantified. One, two-, and four-cell embryos were cultured in Whitten's medium. Mature follicles were present at the earliest time examined (6 h). Thirty-eight percent of females that had been paired for < 12 h after the first copulation ovulated, whereas all females paired >/= 12 h after the first copulation ovulated. Virtually all (> 99%) oocytes recovered from females paired for >/= 12 h after first copulation were fertilized. Pairing time after first copulation and mean copulation-bout duration were significant (p < 0.05) determinants of embryo number. Embryos entered the uterine horns and implanted on Days 3 and 4, respectively, after first copulation (Day 0). Embryos cultured in vitro underwent approximately one cell division per day, a rate similar to that in vivo. We conclude that prairie voles ovulate reliably after pairing for >/= 12 h, although some females showed exceptional sensitivity not predicted by the variables quantified. Prolonged mating for longer than 12 h increased the total embryos produced. This mechanism likely has adaptive significance for increasing offspring number.  (+info)

Effect of pelvic endometrial implants on overall reproductive functions of female rats. (2/462)

The effects of pelvic endometrial implants on the overall reproductive potential of female rats were investigated. After homologous transplantation in the peritoneum, the ectopic endometrium developed into highly vascularized nodes that gradually increased in mass until the 9th week postsurgery and then plateaued. In the presence of these implants, overall reproductive function was adversely affected. The effect was of greatest magnitude during 50-70 days posttransplantation. As compared with values in corresponding controls, ovulation was reduced by 43% (6 of 14) (p < 0.05), mating rate was reduced by 44% (12 of 27) (p < 0.025), and premature termination of pregnancy occurred in 34% (5 of 15) of rats. Wastage of pregnancy, which included complete termination or reduction of fetal number, occurred during the postimplantation course of gestation. Furthermore, 100% of the rats with transplants failed to respond to the copulomimetic stimulation for the induction of pseudopregnancy (p < 0.01, compared with corresponding controls). However, on exposure to vasectomized males, 46% (6 of 13) of these rats exhibited development of pseudopregnancy (p < 0.05, compared with corresponding group receiving copulomimetic stimulation). Increased rate of mating failure and differential pseudopregnancy rates after copulomimetic and natural cervical stimulation suggest that the rats with endometrial explants possibly had an absence or a short appearance of behavioral estrus. Hormonal assessment during the preovulatory phase showed a tendency toward lower mean levels of preovulatory estradiol and significantly lower LH (p < 0.01) and progesterone (p < 0.01) concentrations. The adversely affected reproductive functions may be a secondary consequence of these altered endocrine milieus.  (+info)

Control of oocyte maturation in sexually mature Drosophila females. (3/462)

In many sexually mature insects egg production and oviposition are tightly coupled to copulation. Sex-Peptide is a 36-amino-acid peptide synthesized in the accessory glands of Drosophila melanogaster males and transferred to the female during copulation. Sex-Peptide stimulates vitellogenic oocyte progression through a putative control point at about stage 9 of oogenesis. Here we show that application of the juvenile hormone analogue methoprene mimics the Sex-Peptide-mediated stimulation of vitellogenic oocyte progression in sexually mature virgin females. Apoptosis is induced by 20-hydroxyecdysone in nurse cells of stage 9 egg chambers at physiological concentrations (10(-7) M). 20-Hydroxyecdysone thus acts as an antagonist of early vitellogenic oocyte development. Simultaneous application of juvenile hormone analogue, however, protects early vitellogenic oocytes from 20-hydroxyecdysone-induced resorption. These results suggest that the balance of these hormones in the hemolymph regulates whether oocytes will progress through the control point at stage 9 or undergo apoptosis. These data are further supported by a molecular analysis of the regulation of yolk protein synthesis and uptake into the ovary by the two hormones. We conclude that juvenile hormone is a downstream component in the Sex-Peptide response cascade and acts by stimulating vitellogenic oocyte progression and inhibiting apoptosis. Since juvenile hormone analogue does not elicit increased oviposition and reduced receptivity, Sex-Peptide must have an additional, separate effect on these two postmating responses.  (+info)

17beta-estradiol rapidly facilitates chemoinvestigation and mounting in castrated male rats. (4/462)

Testosterone and estradiol act synergistically to stimulate male sexual behavior. Previous studies demonstrated that testosterone's actions are mediated genomically. Attempts to show that estradiol acts in a similar fashion have been inconclusive. However, estrogens have been shown to exert short-latency effects by acting directly on neuronal membranes. The present experiment examined whether testosterone or estradiol rapidly facilitates copulatory behaviors in castrated sexually experienced rats. Within 35 min of administration, estradiol stimulated chemoinvestigation and frequency of mounting and reduced mount latency in a dose-dependent manner. In contrast, acute administration of testosterone did not alter sexual activity. These data demonstrate for the first time that estradiol exerts short-latency effects on copulatory behavior, providing indirect evidence that this action is mediated through a nontranscriptional mechanism.  (+info)

Sperm transport and storage in the agile antechinus (Antechinus agilis). (5/462)

This study was an examination of the timing of ejaculation and the dynamics of sperm transport in the female reproductive tract of the agile Antechinus (Antechinus agilis) and the relationship of these parameters to single and multiple matings. Mating in this species is characteristically long compared with that of other mammals, lasting for up to 8-12 h during which time the pair remain locked together. After the first hour of mating, only approximately 40% of males had ejaculated, but by the third hour all males had ejaculated. The total number of spermatozoa extracted from the female tract remained at approximately 30 x 10(3) spermatozoa per side over the next 9 h of copulation. After completion of male/female access (12 h), approximately 56% of spermatozoa extracted were located in the lower isthmic region of the oviduct where specialized sperm storage crypts are located. The number of spermatozoa extracted from the female reproductive tract did not decline over the next 3 days, but there was a change in the distribution of spermatozoa with an increase in the proportion of extracted spermatozoa stored in the lower isthmus (approximately 76%). However, 7 to 14 days after mating, only approximately 30% of the stored spermatozoa ( approximately 9.4 x 10(3) spermatozoa per side) were still present in the isthmus. When females were mated with a second male on a consecutive day, the sperm numbers extracted from the tract were about twice that deposited during single mating, with sperm transport to the lower isthmus occurring over a similar time frame. Although the occurrence of extended copulations in the wild has not yet been confirmed, these laboratory results suggest that similar periods of copulation are likely, since completion of the ejaculation process requires at least 3 h. The extended copulation in A. agilis reduces the possibility of an early second mating, which might interfere with the normal transport and crypt colonization of spermatozoa through competition.  (+info)

Induction of pseudopregnancy in the mongolian gerbil (Meriones unguiculatus) by vaginal stimulation. (6/462)

In rats, pseudopregnancy has been induced by mating with vasectomized males, by mechanical stimulation of the uterine cervix with a glass rod or vibrator, and by stimulation of the vagina with a tampon. On the other hand, no practical data are available in reports on the induction of pseudopregnancy in Mongolian gerbils. Pseudopregnancy of gerbils has been induced by mating with vasectomized males. But this method was uncertain because the incidence of pseudopregnancy was lower than that obtained in rats by other means. In the present study, two experiments were undertaken as follows. 1) Copulatory behavior of gerbils was observed for one hour to determine the most effective stimulation interval. 2) From the results of Experiment 1, female gerbils in estrus were mechanically stimulated to test the effectiveness of inducing pseudopregnancy by vaginal stimulation at various time intervals. The results of these experiments indicated that, although the frequency of copulatory behavior varied among individuals, on average the most effective method for inducing pseudopregnancy was stimulation of 5 min duration and at 20 or 30 min intervals. Because the incidence of pseudopregnancy induced by such mechanical stimulation (83.3%) was higher than that induced by mating with vasectomized males (30.0%), this method might be useful in inducing pseudopregnancy in Mongolian gerbils.  (+info)

TGFbeta-like signaling and spicule development in Caenorhabditis elegans. (7/462)

A TGFbeta-like signal is required for spicule development in Caenorhabditis elegans males. This signal appears to originate in the male-specific musculature and is required for the migrations of cells within the proctodeum. The migrations of these cells form cellular molds, the spicule traces, in which the cuticle of the spicules is secreted. Mutations in daf-4, sma-2, sma-3, and sma-4, which disrupt TGFbeta-like signaling, result in aberrant migrations and morphologically abnormal spicules. daf-4, and hence the TGFbeta-like signal, is required prior to or during cell migrations. Therefore, the TGFbeta-like signal may act to prime the migrating cells or as a guidance cue. Mutations in lin-31 result in identical cell migration and spicule morphology defects. Thus, lin-31, which encodes a "winged helix" protein (Miller et al., Genes Dev. 7, 933-947, 1993), may be a component of this TGFbeta-like signaling pathway.  (+info)

Behavior and endocrine changes in high-performing, low-performing, and male-oriented domestic rams following exposure to rams and ewes in estrus when copulation is precluded. (8/462)

High-performing, low-performing, and male-oriented rams were used to investigate behavior and neuroendocrine correlates of sexual interest and discrimination. Treatment consisted of visual and olfactory contact with stimulus animals through a woven wire fence, which inhibited copulation (either ewes in estrus or other rams), for 4 h on each of three consecutive days. Before exposure to stimulus animals on d 1 and during the final 1 h of exposure on d 2, blood samples were collected every 15 min for 1 h to determine concentrations of LH and testosterone. During exposure to stimulus animals, rams were continuously observed and investigatory behaviors were recorded. There was no day effect for any behavior. Groups of rams differed (P < .05) in amounts of behaviors exhibited, but behaviors were not influenced by sex of stimulus animals. High-performing rams exhibited more (P < .05) investigatory behaviors toward stimulus animals than low-performing or male-oriented rams. Plasma concentrations of LH increased (P < .05) in high-performing rams following exposure to estrous ewes, but not following exposure to rams. In low-performing and male-orientated rams, concentrations of LH were unchanged regardless of sex of the stimulus animal. Change in plasma concentrations of testosterone from pre- to posttreatment did not differ between high-performing, low-performing, and male-oriented rams. However, low-performing rams exhibited an increase (P < .05) in plasma concentrations of testosterone following exposure to rams. In conclusion, high-performing rams exhibit a high degree of investigatory behaviors toward estrous ewes and other rams. High-performing rams seem to discriminate sex of stimulus animals and exhibit a neuroendocrine response (i.e., increased plasma LH) only when exposed to ewes in estrus. The sensory signals provided by estrous females are either not detected by low-performing or male-oriented rams or are not sufficiently provocative to elicit further investigation by these rams.  (+info)

Sexual dimorphism can be achieved using a variety of mechanisms, including sex-specific circuits and sex-specific function of shared circuits, though how these work together to produce sexually dimorphic behaviors require further investigation. Here, we explore how components of the sex-shared defecation circuitry are incorporated into the sex-specific male mating circuitry in Caenorhabditis elegans to produce successful copulation. Using behavioral studies, calcium imaging, and genetic manipulation, we show that aspects of the defecation system are co-opted by the male copulatory circuitry to facilitate intromission and ejaculation. Similar to hermaphrodites, male defecation is initiated by an intestinal calcium wave, but circuit activity is coordinated differently during mating. In hermaphrodites, the tail neuron DVB promotes expulsion of gut contents through the release of the neurotransmitter GABA onto the anal depressor muscle. However in the male, both neuron and muscle take on modified ...
Environmental stimulation results in an increased expression of transcription factors called immediate early genes (IEGs) in specific neuronal populations. In male Japanese quail, copulation with a female increases the expression of the IEGs zenk and c-fos in the medial pre-optic nucleus (POM), a key nucleus controlling male sexual behavior. The functional significance of this increased IEG expression that follows performance of copulatory behavior is unknown. We addressed this question by repeatedly quantifying the performance of appetitive (learned social proximity response) and consummatory (actual copulation) sexual behavior in castrated, testosterone-treated males that received daily intra-cerebroventricular injection of an antisense oligodeoxynucleotide targeting c-fos or control vehicle. Daily antisense injections significantly inhibited the expression of copulatory behavior as well as the acquisition of the learned social proximity response. A strong reduction of the proximity response ...
Most single-species population models assume either that one sex dominates the growth dynamics (usually the female), or that the life cycles of the two sexes are identical; however, sexual differences in ontogenetic features can render this assumption invalid. Further, the interaction between sexes is necessarily nonlinear, and the dependence of dynamic behavior on sexual interactions can be complicated. Here we examine a two-sex population model, related to the well-known logistic model, with explicit sexual interactions. The model is bistable and, by the addition of diffusion, admits traveling wave solutions. Dominance of states via this spatial dynamic are examined. A simple condition for neutral dominance is obtained; sexual interactions inhibit the dominance of the nonzero population, making persistence more difficult.
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The effects of carbon-disulfide (75150) (CS2) on a reproductive function were examined in male Long-Evans-Hooded-rats. Rats were exposed to 607 parts per million CS2 in a exposure chamber for 6 hours per day, 5 days per week, for 10 weeks. Before exposure, baseline values were established for copulation behavior, semen parameters, semen plug weights, and hormone concentrations. Animals were evalua
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In this article, we provide a concise review of the past and current literature on the neglected influence of progesterone on male sexual behavior. Although there has been increased interest in all aspects of male sexual function, and the importance of androgens in the regulation of male copulatory behavior has long been well documented, knowledge of the role of progesterone on male sexual behavior is still patchy. Very little human data exist on this theme, and most of the literature concerns animal research, in particular reptiles and rodents. This review attempts to outline specific progesterone mechanisms involved in male sexual behavior, showing that this hormone plays a more relevant role in the control of male sexual behavior than commonly assumed. Exploring the neuroendocrine mechanisms of progesterone in the sexual behavior of males may provide insights into the regulation of sexuality in this gender. (c) 2005 Elsevier B.V. All rights reserved ...
in Physiology & Behavior (1990), 47(1), 83-94. A series of 4 experiments was designed to study the relationships between the activity of the aromatase (AA) in the preoptic area (POA) and the activation by testosterone (T) of copulatory behavior in ... [more ▼]. A series of 4 experiments was designed to study the relationships between the activity of the aromatase (AA) in the preoptic area (POA) and the activation by testosterone (T) of copulatory behavior in gonadectomized male and female Japanese quail. The induction of AA by T in the POA is dose- and time-dependent. Levels of AA seen in sexually mature males are restored in castrated birds by a treatment with 20 to 40 mm silastic T capsules which produce physiological levels of steroid in the plasma. The minimal dose of T (10 mm implant) which reliably restores copulatory behavior approximately doubles the AA in the POA. The induction of AA is significantly larger in males than in females. A significant increase in AA is observed within 16 ...
en] Treatment of castrated quail with testosterone (T) reliably activates male copulatory behavior and, at the same time, increases the aromatase activity (AA), the number of aromatase-immunoreactive (ARO-ir) cells and the concentration of aromatase mRNA as measured by RT-PCR in the brain. All these effects can be mimicked by estrogens. The behavioral effects of T can be blocked by a variety of aromatase inhibitors and, in parallel, the AA is strongly inhibited in the preoptic area (POA). We showed recently that the steroidal inhibitor, 4-OH-androstenedione (OHA) markedly decreases the immunostaining density of brain ARO-ir cells while the non-steroidal inhibitor, R76713 (racemic Vorozole; VOR) unexpectedly increased the density of this staining, despite the fact that the enzyme activity was completely inhibited. To generalize these findings and try to identify the underlying mechanism, we compared here the effects of two steroidal (OHA and androstatrienedione [ATD]) and two non-steroidal (VOR ...
Female copulatory vocalizations, also called female copulation calls or coital vocalizations are produced by female primates, including human females, and female non-primates. Copulatory vocalizations usually occur during sexual intercourse and are hence related to sexual activity. Vocalizations that occur before intercourse, for the purpose of attracting mates, are known as mating calls. In primates, copulation calling is typically observed at the end of mating and there are vast variations between species regarding its occurrence, frequency and form. It is agreed that coital vocalizations fulfill an evolutionary purpose and that they serve as adaptive solutions to problems that the females face, such as infanticide, as well as obtaining high quality sperm. In non-primates, copulatory calling predominantly occurs before copulation in order to attract mates (mating call). Calls vary in frequency (14 Hz to 70,000 Hz) and function. One of the main purposes of females vocalizing is the induction of ...
Sex steroid hormones activate diverse vertebrate reproductive behaviors by their actions on central and peripheral tissues. In reproductively active males, gonadal testosterone (T) increases aggressive behavior, as well as appetitive (courtship) and consummatory (copulatory) behavior. To achieve these effects, T acts on neural circuits and/or skeletal muscles that motivate behavioral performance and enhance motor output [1-3]. The actions of T often require its metabolic conversion into one or more active products. In brain, for example, T is converted into estradiol by the enzyme aromatase; in turn, this estrogen acts via estrogen receptors on discrete neural circuits to facilitate the performance of copulatory and aggressive behaviors, as well as a variety of other neural functions [1].. In many male reproductive tissues, T undergoes conversion into the potent androgen 5α-dihydrotestosterone (5α-DHT) by one of two main isoforms (types 1 and 2) of the enzyme 5α-reductase [4-6]. This 5α-DHT ...
Two major theories on vision prevailed in classical antiquity. The first theory, the emission theory, was supported by such thinkers as Euclid and Ptolemy, who believed that sight worked by the eye emitting rays of light. The second theory, the intromission theory supported by Aristotle and his followers, had physical forms entering the eye from an object. Previous Islamic writers (such as al-Kindi) had argued essentially on Euclidean, Galenist, or Aristotelian lines. The strongest influence on the Book of Optics was from Ptolemys Optics, while the description of the anatomy and physiology of the eye was based on Galens account.[50] Alhazens achievement was to come up with a theory that successfully combined parts of the mathematical ray arguments of Euclid, the medical tradition of Galen, and the intromission theories of Aristotle. Alhazens intromission theory followed al-Kindi (and broke with Aristotle) in asserting that "from each point of every colored body, illuminated by any light, ...
in Trabajos del Instituto Cajal (2005), 80. One of the best-characterized actions of steroids is the regulation of brain areas involved in endocrine function and in the activation of reproductive behaviors in male and female vertebrates. Progress ... [more ▼]. One of the best-characterized actions of steroids is the regulation of brain areas involved in endocrine function and in the activation of reproductive behaviors in male and female vertebrates. Progress in the understanding of the mechanisms that control the expression of the eukaryotic genome by nuclear receptors has brought forward the importance of steroid receptor coactivators in mediating efficient gene transcription. However, little is know about the specific physiological requirements of these coactivators in vivo. In Japanese quail, testosterone treatment of castrated males restores the full copulatory behavior and increases the volume of the sexually dimorphic medial preoptic nucleus (POM) to the level observed in intact males ...
The C. elegans hook sensillum is a male copulatory structure developed from the hook sensillum competence group (HCG), P(9-11).p. Male P(9-11).p each adopt one of three potential fates (1º, 2º, or 3º), forming an invariant spatial pattern of 3º-2º-1º. I examined HCG fate specification in various genetic backgrounds and found that both lin-17 Frizzled-like Wnt receptor and bar-1 [beta]-catenin are predominantly expressed in 1º P11.p. Activation of the bar-1 canonical Wnt pathway by a pry-1(Axin) mutation changes the competence of the anterior P(3-8).p cells and induces ectopic 1º HCG fate. I also found that the Hox gene mab-5 acts downstream of the Wnt pathway to determine HCG competence. Ectopic mab-5 expression, in conjunction with activated LIN-12 or EGF signaling, causes ectopic HCG fates in anterior P(1-8).p. Furthermore, epistatic interactions between lin-17 and lin-12 showed that generation of 2º HCG fate in P10.p by LIN-12/Notch activity depends on LIN-17-mediated Wnt signaling. ...
Dorsal soft rays (total): 62-70; Anal soft rays: 58 - 61; Vertebrae: 45 - 47. This species is distinguished by the following set of characters: vertebrae 11-12 + 34-35 = 45-47; D 62-70, A 58-61, pectoral-fin rays 14, caudal-fin rays 6; anterior dorsal fin ray above vertebra 7-8; anterior anal fin ray below dorsal fin ray 14-15; anterior anal fin ray below vertebra 14; small forward-curved spine at lower angle of preopercle; head with separated scale patches on cheeks, operculum and occiput; papillae on lower jaw only; posterior mandibular pores absent; no lower preopercular pores; minute palatine teeth in single row; otolith length to otolith height, 2.0, otolith length to colliculum length, 2.4; male copulatory organ with 3 small papillae at base of genital hood (Ref. 88975). ...
The effect of perceived predation risk on male courtship and copulatory behavior in the wolf spider Pardosa milvina (Araneae, Lycosidae) ...
A pair of Andean condors may select a nest site and then roost in (or near) it for as much as two and a half months before mating actually begins. As the pair mate and the time draws near to the female laying their egg, they will gradually begin to roost closer and closer to the nest ledge until they are finally roosting overnight inside it.. The mating behavior of Andean condors differs between accounts in zoo settings and the limited observations of wild birds. Accounts of wild birds have been made at great distances without clear views or description of the display or copulatory behavior. The male display can begin with pre-display behavior that includes the male rubbing his head and neck against a tree or post. Also the male has been described to present the female with small twigs and straws that they both lodge in their wing feathers, immediately followed by the object falling to the ground. These behaviors were not observed in all cases, and no definite explanation was offered. It is ...
Most of the details of reproduction in wild populations are from the western dry deciduous forests; determining whether or not certain of these details are applicable to eastern populations will require further field research.[15] Mating typically occurs during September and October,[4] although there are reports of its occurring as late as December,[15] and can be highly conspicuous.[9] In captivity in the Northern Hemisphere, fossas instead mate in the northern spring, from March to July.[16] Intromission usually occurs in trees on horizontal limbs about 20 m (66 ft) off the ground. Frequently the same tree is used year after year, with remarkable precision as to the date the season commences. Trees are often near a water source, and have limbs strong enough and wide enough to support the mating pair, about 20 cm (7.9 in) wide. Some mating has been reported on the ground as well.[15]. As many as eight males will be at a mating site, staying in close vicinity to the receptive female. The female ...
Depth range from type locality (Ref. 329); to be replaced with a better reference. Members of the order Decapoda are mostly gonochoric. Mating behavior: Precopulatory courtship ritual is common (through olfactory and tactile cues); usually indirect sperm transfer (Ref. 833). ...
Members of the order Decapoda are mostly gonochoric. Mating behavior: Precopulatory courtship ritual is common (through olfactory and tactile cues); usually indirect sperm transfer (Ref. 833). ...
Members of the order Decapoda are mostly gonochoric. Mating behavior: Precopulatory courtship ritual is common (through olfactory and tactile cues); usually indirect sperm transfer (Ref. 833). ...
Recent studies show early exposure to BPA can change male behavior in adulthood. Male mice showed less masculine behavior (less territorial marking).
My Guru, Adi Da Samraj, used many skillful means to bring his students in contact with their hidden agenda, while at the same time bringing them in contact with His free State of being . One of those means was sexual activity. After a while He did not use those means any longer. It was not necessary anymore, because we got the lesson We learned that it was His Being, His State of ultimate Freedom that enlightens the disciple. It is the effect of Good Company that allows the atmosphere to break open, to see what is our obstructions. Those sexual interactions were just done for the sake of instruction. Now it is clear that anytime when the student meditates in the Gurus Company the student meditates on the Gurus Realization, on Reality Itself. That is completely sufficient. All kinds of life problems arise daily, but in meditation on the Gurus Free State of Being , by that Grace, one can stand prior to what is arising and one can act in freedom relative to it. That is the Truth.. and I am glad ...
My Guru, Adi Da Samraj, used many skillful means to bring his students in contact with their hidden agenda, while at the same time bringing them in contact with His free State of being . One of those means was sexual activity. After a while He did not use those means any longer. It was not necessary anymore, because we got the lesson We learned that it was His Being, His State of ultimate Freedom that enlightens the disciple. It is the effect of Good Company that allows the atmosphere to break open, to see what is our obstructions. Those sexual interactions were just done for the sake of instruction. Now it is clear that anytime when the student meditates in the Gurus Company the student meditates on the Gurus Realization, on Reality Itself. That is completely sufficient. All kinds of life problems arise daily, but in meditation on the Gurus Free State of Being , by that Grace, one can stand prior to what is arising and one can act in freedom relative to it. That is the Truth.. and I am glad ...
Tobacco Road és una pel·lícula de 1941 dirigida per John Ford i protagonitzada per Charley Grapewin, Marjorie Rambeau, Gene Tierney, William Tracy i Dana Andrews. Es tracta duna adaptació de la novel·la del mateix nom de lescriptor Erskine Caldwell publicada lany 1932. Retrat dels blancs pobres de Georgia i de la seva actitud immoral davant la vida, en un moment en què les terres estan habitades per la misèria. La pel·lícula evidencia les circumstàncies en què fou rodada per aprofitar el gran èxit popular de El raïm de la ira de lany anterior i amb constants intromissions del productor Zanuck que va incloure en els acabats el seu toc personal i propi de la 20th Century Fox.[1] ...
We hit the asphalt road to the Fish Hatchery side by side and ran into the aid station the same way in 3:06. I was a bit more efficient with my crew, so I headed back out a little before Tim but he soon rejoined me and we cruised down the black-top, both shirtless in anticipation of the rising sun in the cloudless sky on the shadeless road. Bottom line, we both ran way too fast through here over to Treeline/Pipeline. It wasnt a hard effort because we were both fit and rested and ready to roll but the entire time I was constantly reminding myself to slow the F down, this is 100 miles we have to run today, and whenever I would consciously slow Timmy would do the same, but always half-stepping, always wanting to go just a bit faster and before I would know it I would be right there by his side again. It was frustrating for me to get distracted by this sort of external stimulus. Either way, we hit the Pipeline turn-off (normally the "Treeline" crew access point, the Pipeline section being a course ...
We hit the asphalt road to the Fish Hatchery side by side and ran into the aid station the same way in 3:06. I was a bit more efficient with my crew, so I headed back out a little before Tim but he soon rejoined me and we cruised down the black-top, both shirtless in anticipation of the rising sun in the cloudless sky on the shadeless road. Bottom line, we both ran way too fast through here over to Treeline/Pipeline. It wasnt a hard effort because we were both fit and rested and ready to roll but the entire time I was constantly reminding myself to slow the F down, this is 100 miles we have to run today, and whenever I would consciously slow Timmy would do the same, but always half-stepping, always wanting to go just a bit faster and before I would know it I would be right there by his side again. It was frustrating for me to get distracted by this sort of external stimulus. Either way, we hit the Pipeline turn-off (normally the "Treeline" crew access point, the Pipeline section being a course ...
For More Than 100 Years, Rock Products has Been the Leading Voice of the Aggregates Industry A solid infrastructure is the key to a sound economy. And the nations infrastructure is dependent upon aggregates production. More than 90 percent of asphalt road pavement, and more than 80 percent of a concrete sidewalk, for instance, is comprised of aggregates. Rock Products is the leading source of industry information for U.S. and Canadian aggregates operations. Since 1896, stone producers have turned to Rock Products for market analysis and technology solutions. Rock Products industry-specific content, from its monthly print publication, special supplements and directories; to its website, digital editions and e-news alerts, maintains the same high editorial standard that was set more than a century ago.
For More Than 100 Years, Rock Products has Been the Leading Voice of the Aggregates Industry A solid infrastructure is the key to a sound economy. And the nations infrastructure is dependent upon aggregates production. More than 90 percent of asphalt road pavement, and more than 80 percent of a concrete sidewalk, for instance, is comprised of aggregates. Rock Products is the leading source of industry information for U.S. and Canadian aggregates operations. Since 1896, stone producers have turned to Rock Products for market analysis and technology solutions. Rock Products industry-specific content, from its monthly print publication, special supplements and directories; to its website, digital editions and e-news alerts, maintains the same high editorial standard that was set more than a century ago.
Wherever albedo values are less than 100%, some of the sunlight that strikes Earths surface is absorbed instead of reflected. As a surface absorbs solar radiation, it becomes warm and radiates heat energy to the air around it. For example, an asphalt road that absorbs solar radiation through the day becomes very hot, warming the air above it.. Watch the visualization below to see what happens to the light energy that is not reflected. Red arrows represent heat energy radiated by the surface.. ! Click the image to see the animation.. ...
Dogs - Cats - Terrific Pets is a website you can find information on dog breeds, dog breeders, dogs for sale, puppies for sale, dog names and more.
Bruvo-Madaric B., Huber B.A., Steinacher A., Pass G. 2005. Phylogeny of pholcid spiders (Araneae:Pholcidae): combined analysis using morphology and molecules. Molecular Phylogenetics and Evolution 37: 661-673.. Eberhard W.G., Brice o R.D. 1983. Chivalry in pholcid spiders. Behav. Ecol. Sociobiol. 13: 189 195.. Gerhardt U. 1921. Vergleichende Studien ber die orphologie des m nnlichen Tasters und die Biologie der Kopulation der Spinnen. Arch. Naturgesch. 87: 78 247.. Gerhardt U. 1923. Weitere sexualbiologische Untersuchung an Spinnen. Arch. Naturgesch. 89: 1 225.. Gerhardt U. 1924. Weitere Studien ber die Biologie der Spinnen. Arch. Naturgesch. 90: 85 192. Gerhardt U. 1927. Neue biologische Untersuchungen an einheimischen und ausl ndischen Spinnen. Z. Morph. kol. Tiere 8: 96 186.. Gerhardt U. 1929. Zur vergleichenden Sexualbiologie primitiver Spinnen, insbesondere der Tetrapneumonen. Z. Morph. kol. Tiere 14: 699 764.. Huber B.A. 1994. Genital morphology, copulatory mechanism and reproductive ...
Mounting a Silentia screen can be performed in many different ways. A large number of mounting options makes it flexible enough to fit into any healthcare environment anywhere.
The role of olfaction, that is to say of the main olfactory system, in sexual behavior is not much better known than that of the vomeronasal system. If, to make things easy, we start with its role in copulatory behavior, a review of existing data tells us that the importance of the main olfactory system is modest. We have already insinuated that the elimination of olfactory input has variable effects. Early studies (Stone, 1922) showed that anosmia did not modify the copulatory behavior of male rats, not even in their first encounter with a receptive female. This observation was confirmed about 50 years later (Cain and Paxinos, 1974). However, later studies have not always replicated this observation. For example, Bergvall et al. (1991) reported that peripheral anosmia reduced the intensity of male rat copulatory behavior when the subjects had been anosmic for a month. After one week, though, their behavior was unaffected. Anosmia-induced degeneration of neurons in the olfactory bulb may be the ...
In rodents, sexual behavior depends on the adequate detection of sexually relevant stimuli. The olfactory bulb (OB) is a region of the adult mammalian brain undergoing constant cell renewal by continuous integration of new granular and periglomerular neurons in the accessory (AOB) and main (MOB) olfactory bulbs. The proliferation, migration, survival, maturation, and integration of these new cells to the OB depend on the stimulus that the subjects received. We have previously shown that 15 days after females control (paced) the sexual interaction an increase in the number of cells is observed in the AOB. No changes are observed in the number of cells when females are not allowed to control the sexual interaction. In the present study we investigated if in male rats sexual behavior increases the number of new cells in the OB. Male rats were divided in five groups: 1) males that did not receive any sexual stimulation, 2) males that were exposed to female odors, 3) males that mated for 1 h and could not
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in Trabajos del Instituto Cajal (2009), LXXXII. Steroid receptors such as estrogen receptors alpha and beta and androgen receptors are transcription factors involved in the transcriptional regulation of a large number of target genes. Steroid-dependent ... [more ▼]. Steroid receptors such as estrogen receptors alpha and beta and androgen receptors are transcription factors involved in the transcriptional regulation of a large number of target genes. Steroid-dependent expression in the brain controls a large array of biological processes including spatial cognition, copulatory behavior and neuroprotection. The discovery of a competition, or squelching, between two different nuclear receptors introduced the notion that common cofactors might be involved in the modulation of transcriptional activity of nuclear receptors. These cofactors, which are now known as coactivators, are involved in chromatin remodeling and stabilization of the general transcription machinery. Since the characterization of ...
Blum K, Werner T, Carnes S, Carnes P, Bowirrat A, Giordano J, Oscar-Berman M, Gold M (2012). "Sex, drugs, and rock n roll: hypothesizing common mesolimbic activation as a function of reward gene polymorphisms". Journal of Psychoactive Drugs. 44 (1): 38-55. doi:10.1080/02791072.2012.662112. PMC 4040958. PMID 22641964. It has been found that deltaFosB gene in the NAc is critical for reinforcing effects of sexual reward. Pitchers and colleagues (2010) reported that sexual experience was shown to cause DeltaFosB accumulation in several limbic brain regions including the NAc, medial pre-frontal cortex, VTA, caudate, and putamen, but not the medial preoptic nucleus. Next, the induction of c-Fos, a downstream (repressed) target of DeltaFosB, was measured in sexually experienced and naive animals. The number of mating-induced c-Fos-IR cells was significantly decreased in sexually experienced animals compared to sexually naive controls. Finally, DeltaFosB levels and its activity in the NAc were ...
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On the other hand, relationships benefit when both partners develop positive self-images. Individuals who have a healthy self-concept are often more open, expressive, and intimate with their significant others, which leads to more secure attachments. This is because when people perceive themselves as loveable and trustworthy, they will be more likely to openly and securely love and trust their partners.. Being self-confident also has a positive effect on peoples satisfaction with their sexuality and sexual interactions. Pleasurable sexual activities require disclosure of private aspects of the self that people with poor body images are often uncomfortable with. People who are discontented with their bodies often experience sexual problems, such as the inability to orgasm, while individuals who are comfortable and secure with their bodies often find their sexual experiences to be more enjoying and fulfilling. Being confident and familiar with your body will improve almost any sexual ...
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INTERESTED IN A ROAD BIKE TOUR OUT OF THE ORDINARY? Ethiopia is an wonderful country to visit - also when it comes to cycling.. A network of asphalt roads spreads out from the capitol Addis Ababa to different corners of the country. They take you either through warm savanna, or hot desert, through fertile middle hills or the highlands. The variation is enormous, the landscape is breathtaking, and the opportunities are many. We are a Danish provider of road bike tours in Ethiopia. We arrange road bike tours that are both challenging and rewarding ...
I distinctly remember the very first time ejaculation happened to me. It was on a first play-date with a new partner, and he just sorta *ahem* "hit the spot". I didnt know my body was capable [...]. » to read the rest of "27 February 2010 - On Female Ejaculation" click here « ...
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In male New Zealand white rabbits, it was shown that oxytocin but not vasopressin concentrations in plasma were markedly raised after ejaculation. In male Wistar rats, oxytocin infused into the internal carotid artery reduced the number of intromissions made before ejaculation but had no other significant effect. Infusion of oxytocin into the third ventricle increased the latencies to the first mount and intromission and lengthened post-ejaculatory refractory periods. It is suggested that oxytocin released into the periphery during coitus, while not essentially involved in ejaculation, may exert effects on the genital periphery. Behavioural effects of centrally administered oxytocin suggest that it may play a role in the neural mechanisms underlying post-ejaculatory refractoriness.. J. Endocr. (1985) 107, 97-106 ...
I have observed more than sixty matings in species of Aracamby and registered thirty copulation durations, which ranged from 23 to 58 minutes. In some instances the females visibly intended to abort the process by trying to remove the male with her hind legs and jumping, but never succeeded. Whenever she jumped the male was also carried with her, so tightly attached they were.. Normally, for copulation to occur in crickets, the female must allow it because she has to protrude her copulatory papilla upon response to male courtship in order to permit genital attachment; without her compliance copulation will not occur. Forced copulation in crickets is thus a hardly conceivable phenomenon; nevertheless, it was observed three times in couples of two different species of Aracamby placed in small terraria in the laboratory. Presumably it also occurs in nature.. According to the laboratory observations, this is the scenery in which forced copulations took place: imediately after last moult, when the ...
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New World opossums are infected by a variety of parasites, including intestinal nematodes from the genus Travassostrongylus. Travassostrongylus encompasses 10 known species and is included in the richest superfamily of parasitic nematodes, Trichostrongyloidea. Using pointed ridges that run along their body, these worms constrict around microvilli in the walls of the intestine and feed on blood. The arrangement of the ridges aids in classification, as do the finger-like structures on the male copulatory bursa, which is a lobular tail that embraces the female during copulation. Species in the genus Travassostrongylus are found in Central and South American opossums. From the semi-aquatic marsupial Chironectes minimus, to the arboreal mouse opossum Marmosa, to the generalist Didelphis, this parasite infects a diverse group of mammals ...
Sex differences in brain structure and function are widespread (Jazin and Cahill, 2010) and analysis of their functional significance has become a priority in the neurosciences (Clayton and Collins, 2014). Interestingly, these sex differences also affect rapid brain estrogen effects (Krentzel and Remage-Healey, 2015). Blocking brain estrogen action/synthesis decreases male sexual motivation within minutes without affecting sexual performance in quail (Seredynski et al., 2013). Here we confirm that blockade of brain aromatase acutely and robustly alters male sexual motivation. This effect is prevented within 15 min by a central injection of E2 or a specific agonist of ERβ, but not of ERα. Furthermore, E2 cannot restore this behavior when mGluR1a is blocked. Together with the previous demonstration that these effects are membrane initiated (Seredynski et al., 2013), the acute modulation of sexual motivation by E2 thus seems to depend on its binding to membrane ERβ, leading to the ...
Darwinian fitness in holometabolous insects like the fruit fly Drosophila melanogaster is reported to be positively correlated with body size. If large individuals in a population have higher fitness, then one would expect directional selection to operate leading to uniformly large individuals. However, size polymorphism persists in nature and needs further probing. We assessed the effect of body size on some of the fitness and fitness-related traits in replicate populations of genotypically large, genotypically small and phenotypically small D. melanogaster flies. In this study, the time taken to attain reproductive maturity and copulation duration were independent of fly size. Fecundity and longevity of large females were significantly higher when they partnered genotypically small males than when they were with genotypically larger or phenotypically small males. The increased female longevity when in association with genotypically small males was not due to selective early death of males that ...
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Paternal care and infanticide by males lie at opposite ends of a continuum of male behaviour towards infants. Hypotheses to explain the evolution of paternal care include enhanced offspring survival, male reproductive strategy to guarantee future mating opportunities or to reduce sperm competition. These hypotheses make different predictions in relation to the conditions that favoured the evolution of paternal care, such as certainty of paternity, mating system, ability of males to monopolize receptive females, presence of alternative strategies to secure paternity or simply the lack of alternative mating opportunities. Likewise, infanticide by males is supposed to enhance the likelihood of paternity of infanticidal males and its occurrence is predicted when females have relatively long lactation, are polyestrous, reproduce aseasonally, and can be monopolized ...
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A content analysis of workplace sexual interactions, informed by past research on sexual harassment in televised workplaces, was conducted of 100 U.S. broadcast, cable, and Internet television program
Dickman, C.R.; Parnaby, H.E.; Crowther, M.S.; King, D.H. 1998: Antechinus agilis (Marsupialia: Dasyuridae), a new species from the A. stuartii complex in south-eastern Australia. Australian journal of zoology, 46(1): 1-26. doi: 10.1071/ZO97036 ...
Survival in hypoxia, oxygen-limitation of respiration and effects of hypoxia on precopulatory mate-guarding behavior of the amphipod, Gammarus pseudolimnaeus, were tested to determine if seasonal hypoxia in Lake Taneycomo could be a limiting factor for amphipods in the lake. Currently, the Army Corps of Engineers uses oxygenation procedures at Table Rock Dam to defend 4.0 ppm dissolved oxygen (D.O.) in water entering Lake Taneycomo. However, little information exists to indicate whether this level of oxygenation is sufficient for survival, growth, and reproduction of G. pseudolimnaeus. Male, female, and juvenile amphipods survived 48 hours exposure to dissolved oxygen below the minimum daily average that is currently defended in the lake. Survival of hypoxia below 3.5 ppm was differed among genders and age with females being most sensitive, and juveniles being least sensitive. Sensitivity to hypoxia increased with an increase in temperature. Respiration of adult G. pseudolimnaeus was found to be oxygen
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One explanation offered by Dr. Marie-Elise Parent was that "having many female sexual partners results in a higher frequency of ejaculations". This is quite bizarre. It might make some sense if each partner were available for only one ejaculation. The majority (but not all) of the women I have had sex with were up for quite a few more than the one ejaculation. And I suspect that I am not unusual in that regard. Furthermore I have it on good authority that most men are able to ejaculate in the absence of a partner. And considering the periods in my life when I had a partner and when I didnt, I might go so far as to say that maybe having a partner results in reduced frequency of ejaculations. ...
Aepyprymnus rufescens is polyestrous, with an estrus cycle occurring approximately every 34 days. Breeding can occur at any time during the year, but there is insufficient data from both captive and wild species to indicate a particular breeding season. Females reach sexual maturity in the 11th month, males between 12 and 13 months. Males visit female nests within their territory every night to determine if the female is sexually receptive. As the female approaches ovulation, the male waits either by the female or by her nest until she is sexually receptive. Both sexes can let out low growls during investigational behavior, which usually includes sniffing of the female by the male. A receptive female allows the male to smell her cloacal and pouch areas, and eventually permits copulation (Ganslosser, 1990).. Males will try to mount the female regardless of warning signals exhibited by unreceptive females. These females try to drive away courting males by making loud growling sounds, striking at ...
It might be easier to think of this in terms of light rail running on a street, but with steerable rubber wheels to give it flexibility. The aim is to have high capacity service and lower operating costs like rail based systems and the flexibility of buses.. The flexibility comes in handy when you consider all the situations when a street might be blocked/closed off. Weve all seen crane and construction collapses, building fires, unstable buildings, parades, street fairs, police investigations, street reconstruction, utility work, and VIP related closures (UN General Assembly, President in town) among other street disruptions.. The concrete would last longer than steel rails or asphalt road surfaces, so would pay for themselves over time.. The investment necessary to setup manufacturing would be expensive if the procurement was small, so a large fleet is necessary to keep per unit costs down. Firms with experience with rail and bus systems, or a consortium of firms with the know how, would be ...
How to Use Blast Technique To Increase Sexual Stamina By Edward White Many men think that the only way to correct the problem of premature ejaculation is to try harder not to come while having sex with their partners. Theyll grit their teeth, think of their friends grandma, count backwards from 1000-theyll do whatever they can to distract themselves from the fact that theyre close to climaxing. The truth is, sometimes the best way to extend your sexual performance is to learn techniques that are designed to be used when you arent having sex. The Blast concept is one such technique. You should try to perform this whole thing in the shower, because it can be a tad messy. Plus, any noise thats created is masked by the sound of the falling water. Its just nicer, to be honest-warm and convenient. Its also a time that is scheduled in your daily life. So if you have a shower every morning, you can use this technique during it, at the same time every other day. This helps you to avoid ...
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How to Use Blast Technique To Increase Sexual Stamina By Edward White Many men think that the only way to correct the problem of premature ejaculation is to try harder not to come while having sex with their partners. Theyll grit their teeth, think of their friends grandma, count backwards from 1000-theyll do whatever they can to distract themselves from the fact that theyre close to climaxing. The truth is, sometimes the best way to extend your sexual performance is to learn techniques that are designed to be used when you arent having sex. The Blast concept is one such technique. You should try to perform this whole thing in the shower, because it can be a tad messy. Plus, any noise thats created is masked by the sound of the falling water. Its just nicer, to be honest-warm and convenient. Its also a time that is scheduled in your daily life. So if you have a shower every morning, you can use this technique during it, at the same time every other day. This helps you to avoid ...
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An SSRI created specifically to deal with untimely ejaculation, referred to as dapoxetine (Priligy), has been certified in the united kingdom. Neighborhood NHS authorities can decide to prescribe it regarding the NHS. It functions considerably faster than the SSRIs mentioned previously and that can be properly used "on demand". Youll usually be encouraged to go on it between 1 and 3 hours before intercourse, not more often than once just about every day. Your reaction to the therapy will be reviewed after then 30 days (or after 6), and once once again every a few months. Dapoxetine is certainly not suited to all guys clinically determined to have early ejaculation. As an example, it is really not suitable for some males with heart, liver and kidney dilemmas. It may also connect to other medications, such as for instance other antidepressants. Typical negative effects consist of: ...
A recent change to UK law has banned activities such as female ejaculation and face-sitting, amongst other things, when filmed and sold by porn producers in the UK. It does not ban male ejaculation. The law was not discussed in parliament, meaning it was passed undemocratically. In April I had ...
For what sexual motivations are concerned, it is in this context interesting to draw upon a recent survey, conducted in Germany (sample size approximately 2500, as reported in "Machen Tattoos sexy?" forschung SPEZIAL. Das Magazin der Deutschen Forschungsgemeinschaft, 2/07, 22-25). More than 10% of men and more than 8% of women were tattooed. The age range that currently dominates the wedding market (18-36 years) has the largest fraction of tattooed people. Men are more likely to be tattooed on arms and legs, whereas women prefer places that can easily be covered by cloths: back, belly, bottom. Not so surprisingly, men prefer designs with skulls, weapons and such, whereas women prefer flowers and animals. Maybe the most interesting fact though is that while only 8% of women had a tattoo, 56% of the participants with a tattoo had a partner who was also tattooed. So theres clearly some matching going on there. Another study in which participants were shown images of tattooed people revealed that ...
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Our data support the hypothesis that courtship directly increases a males paternity success under polyandry, independent of male quality and of male copulation success. Hence, an influence of the courtship display carries over to episodes that occur after the actual copulation and after the male has vanished.. Interestingly, the effect of courtship on paternity in A. bruennichi appears not to be mediated by measures such as prolonged copulations, because short-courting and long-courting males did not differ in copulation duration. Unlike in some other spiders (e.g. Snow & Andrade 2004), copulation duration in A. bruennichi is directly related to sperm transfer and relative paternity success (Schneider et al. 2006). This suggests that the courtship display influences paternity success via a different mechanism from that shown for sexual cannibalism, which increases paternity success by prolonging copulation (Elgar 1998; Elgar & Schneider 2004, this study). We found that courtship decreased the ...
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Background: The koala, Phascolarctos cinereus, is a biologically unique and evolutionarily distinct Australian arboreal marsupial. The goal of this study was to sequence the transcriptome from several tissues of two geographically separate koalas, and to create the first comprehensive catalog of annotated transcripts for this species, enabling detailed analysis of the unique attributes of this threatened native marsupial, including infection by the koala retrovirus. Results: RNA-Seq data was generated from a range of tissues from one male and one female koala and assembled de novo into transcripts using Velvet-Oases. Transcript abundance in each tissue was estimated. Transcripts were searched for likely protein-coding regions and a nonredundant set of 117,563 putative protein sequences was produced. In similarity searches there were 84,907 (72%) sequences that aligned to at least one sequence in the NCBI nr protein database. The best alignments were to sequences from other marsupials. After applying a
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In animals the operational sex ratio is typically shifted towards males, i.e. within a given population there are usually more receptive males than females available at any point in time [1-3]. Consequently, male reproductive success is often limited by access to receptive females, while females are able to choose among several prospective partners [1-3]. Therefore, sexual selection in males often favours traits increasing the number of matings and / or sperm competitive ability [4, 5]. Correlates of male reproductive success are, for instance, traits related to the resource holding potential such as body mass, fat content, weaponry, persistence and aggressiveness [6-8] or sperm number and motility [9, 10].. In addition to male competitive ability, female choice is clearly important in determining male reproductive success [11, 12]. In fact, females may preferably mate with males showing a high resource holding potential / competitive ability which may directly benefit their offspring, or with ...
Copulation[edit]. Main article: Sexual intercourse. Human reproduction naturally takes place as internal fertilization by ... Human reproduction normally begins with copulation, followed by nine months of pregnancy before childbirth, though it may be ...
RFC at Talk:Copulation#Should_the_Copulation_article_exist.3F. You may want to participate in the RFC at Talk:Copulation#Should ... the_Copulation_article_exist.3F --Philcha (talk) 12:05, 9 April 2011 (UTC) ...
Desert locusts in copulation. No taxonomic distinction is made between locust and grasshopper species; the basis for the ...
Copulation in tiger moth. Many of the caterpillars and adults are active during the daytime; however, most species of this taxa ...
Copulation may last 25 minutes.[22] The red kangaroo has the typical reproductive system of a kangaroo. The neonate emerges ...
Males tries to defeat other males by biting the opponent's legs and taking the head between his jaws.[39] Copulation begins ... Copulation takes from 7 to 35 minutes, averaging 11 to 15 minutes. Normally, three to four ejaculations occur.[14] The semen of ...
... and the females mentally and physically become receptive to copulation. It is only during estrus that copulation will result in ... CopulationEdit. "Copulatory tie" redirects here. For copulatory tying in non-canine animals, see Fossa (animal) § Breeding, ... As with most tetrapods, canine copulation involves the male mounting the female from behind, a position that is referred to as ... Virgin dogs can become quite distressed at finding themselves unable to separate during their first copulation, and may try to ...
After repeated mountings, copulation is brief.[citation needed] Water deer have been known to produce up to seven young, but ...
The male flea dies after copulation. The female flea continues in vivo development, described in stages by the Fortaleza ...
... copulation occurs in the burrows, and this reduces the risk of interruption by a competing male. They are also at ... When copulation is over, the male is no longer interested in the female sexually, but will prevent other males from mating with ... Hoogland, J. L. (1998). "Estrus and Copulation of Gunnison's Prairie Dogs". Journal of Mammalogy. 79 (3): 887-897. doi:10.2307/ ...
... meaning that copulation occurs in June or July, but the zygote does not implant into the uterine wall until months later in ... "Fellatio by Fruit Bats Prolongs Copulation Time". PLOS One. 4 (10): e7595. Bibcode:2009PLoSO...4.7595T. doi:10.1371/journal. ...
In males, penis length is 9.6 to 11.8 mm (0.38 to 0.46 in) and baculum length is 8.8 to 10.0 mm (0.35 to 0.39 in). Copulation ... Post copulation genital grooming has also been observed. The glans penis of the marsh rice rat is long and robust, averaging ... Copulation time ranges from 7 to 35 minutes, averaging 11-15 minutes. Bulls have a fibro-elastic penis. Given the small amount ... During copulation, the spotted hyena inserts his penis through the female's pseudo-penis instead of directly through the vagina ...
Because these hooks hold onto the female tightly, copulation that lasts up to several hours has been observed. Copulation ... Males have developed hooks near the end of the abdomen, which are used to grasp onto the female during copulation. ...
These are harassment, intimidation, and forced copulation (rape).[7] Evolutionary explanations[edit]. Thornhill and Palmer's A ... who had committed at least one act of violence/coercion towards their partner in the last month had more in-pair copulations ...
In males, the ninth segment bears a pair of claspers for copulation, and the 10th bears anal cerci in both sexes.[3][13] ... The male then reverses onto her abdomen and the female pushes her ovipositor into his genital opening; copulation, with sperm ...
... oral copulation; burglary; arson; train wrecking; mayhem; rape by instrument; carjacking; torture; poisoning (17) the murder ...
Russian copulation • S-1 block cipher • SAFER • Salsa20 • Salt (cryptography) • SAM card • Security Support Provider Interface ...
Music and copulation. Building a stone house to preserve the witches at the Day of Judgement, but the walls were perpetually ...
Copulation then occurred. After copulation, the female returned to sit in the nest until the male fed her again. This behaviour ... The frequent copulations and lengthy stay of the female in the nest suggested incubation but the researchers did not check the ... Frequent copulation was interspersed with joint inspections of the magpie nest. The morning after the aforementioned ...
"Copulation in English." Paris Review #164 Winter 2002-2003, p. 76. Novel, The Girl in the Tangerine Scarf 2006, Carroll & Graf ...
Copulation lasts for 30 minutes in M. quadridens, while in most wasp species, it only lasts a minute or two. It nests in a ... ISBN 978-0-19-530785-6. Kenneth G. Ross & Robert W. Matthews (1991). "Courtship and copulation". The Social biology of wasps. ...
The Roman Snail: Mating and Copulation (Robert Nordsieck). *A dart in the dark ...
... even before copulation. While the cannibalization before the copulation is still puzzling to scientist, there are some theories ... Copulation begins with physical contact and ends when the spermatophore is deposited: Only a few days after the final moult ... Copulation usually takes place in September or October but the eggs overwinter and the larva don't hatch until the following ... Copulation is also known to take longer when cannibalization occurs. It seems advantageous to transfer more sperm in this ...
Even single human observers may cause the hens to fly off and prevent copulation in this very short time span where they are ... About three days after copulation the hen starts laying eggs. In 10 days the clutch is full. The average clutch size is eight ...
For example, the male Panorpa scorpionflies attempt to force copulation. Male scorpionflies usually acquire mates by presenting ... However, some males attempt to force copulation by grabbing females with a specialized abdominal organ without offering a gift. ... 32] Forced copulation is costly to the female as she does not receive the food from the male and has to search for food herself ... gland protein during mating that makes them unattractive to other males and thus prevents females from future copulation.[34] ...
This theory is supported by a quantifiable increase in the duration of copulation among males which are cannibalized, in some ... Females sometimes practice sexual cannibalism, eating their mates after copulation. Mantises were considered to have ... The act of dismounting after copulation is dangerous for males, for at this time, females most frequently cannibalize their ...
Rivnay, E. The tropism effecting copulation in the bed bug. Psyche 1933, 40, 115-120. [Google Scholar] ... Males inject semen directly into the mesospermalage during copulation and the sperm migrates through the hemolymph until ... continual harassment and copulation leads to increased water loss rates of female bed bugs (Figure 1), which suggests that ... unwanted copulation between fifth instar nymphs/males and other conspecific males [32,33,38]. Experimental manipulation of ...
Worm sex and human sex are surprisingly similar-in some ways. HHMI investigator Cornelia Bargmann recently showed that worms and mammals use the same types of brain chemicals, known as neuropeptides, to coordinate their reproductive behaviors.
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Definitions of copulation: *noun: the act of sexual procreation between a man and a woman; the mans penis is inserted into the ... Search for copulation at other dictionaries: OneLook, Oxford, American Heritage, Merriam-Webster, Wikipedia. ...
In cryptography, Russian copulation is a method of rearranging plaintext before encryption so as to conceal stereotyped headers ...
A study of one group found 88% in-pair copulation and 12% extra-pair copulation. However, there is much variability in rates of ... Therefore, extra-pair copulations have a greater cost for women because they put the support and resources that their mate can ... Extra-pair copulation in men has been explained as being partly due to parental investment. Research has suggested that ... Extra-pair copulation (EPC) is a promiscuous mating behaviour in monogamous species. Monogamy occurs when one male mates ...
Most organisms produce offspring to pass on their genetic information and continue the species. Some bacteria and plants achieve this by budding or cloning, creating exact copies of themselves.
Animal Birds Copulations European: 2 assigned downloads, like Arctic Tern Sterna paradisaea, mating, Texel Island, Netherlands ... Similar tags: animal • birds • canadian • copulations • daytime • european • females • goose • jens schmitz • males • outdoor ...
I discuss the fact that in certain animals the processes of ovulation and copulation are coupled. How very efficient in terms ... nice to see that at least some animals are maximizing their chances of successful fertilization with each bout of copulation. ...
First released video footage of Dr. Pek van Andels study Magnetic resonance imaging of male and female genitals during coitus and female sexual arousal.
This means that he will not be able to attain complete or even partially erection for having copulation. Early climax however ...
Sisodia S, Singh B N (1996) Evidence for a positive correlation be-tween duration of copulation and fertility in Drosophila ... Eberhard W G (1994) Evidence for widespread courtship during copu-lation in 131 species of insects and spiders, and ... Male remating in Drosophila ananassae: evidence for interstrain variation for remating time and shorter duration of copulation ... ananassae: shorter duration of copulation during second mating as compared to first mating. J Biosci, 24: 427 431 ...
The size and age at first copulation and spawning of the apple snail, Pomacea canaliculata, were determined at three food ... However, age at first copulation was similar among snails at all food levels. The food level appeared to affect the penis ... Females fed at the low food level delayed both first copulation and spawning longer than those at higher food levels. ... Consequently, their sizes at first copulation and spawning were smaller. The albumen gland of poorly fed snails was smaller at ...
An instance of intergeneric copulation in the family Rhopalidae (Heteroptera): structure, functioning and congruence of the ...
However in the male, both neuron and muscle take on modified functions to promote successful copulation. Males require calcium- ... Caenorhabditis elegans Male Copulation Circuitry Incorporates Sex-Shared Defecation Components To Promote Intromission and ... Caenorhabditis elegans Male Copulation Circuitry Incorporates Sex-Shared Defecation Components To Promote Intromission and ... Caenorhabditis elegans Male Copulation Circuitry Incorporates Sex-Shared Defecation Components To Promote Intromission and ...
... indicating that these molecules obviate the need for copulation in these salamanders. Surprisingly, our finding of side-by-side ... Ancient pheromone blend as an alternative for copulation in internally fertilizing salamanders. Ines Van Bocxlaer1, Dag Treer1 ... Ancient pheromone blend as an alternative for copulation in internally fertilizing salamanders. PeerJ PrePrints 2:e457v2 https ... indicating that these molecules obviate the need for copulation in these salamanders. Surprisingly, our finding of side-by-side ...
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Copulation[edit]. Main article: Sexual intercourse. Human reproduction naturally takes place as internal fertilization by ... Human reproduction normally begins with copulation, followed by nine months of pregnancy before childbirth, though it may be ...
Copulation. The male centipedes deposit a package of sperm for the female to find and take up to combine with her eggs. Some ...
Copulation was invented by ancient fish. Posted Mon, 20 Oct 2014 14:20:43 GMT by Dave Armstrong ...
Copulation was invented by ancient fish. Posted Mon, 20 Oct 2014 14:20:43 GMT by Dave Armstrong ...
RFC at Talk:Copulation#Should_the_Copulation_article_exist.3F. You may want to participate in the RFC at Talk:Copulation#Should ... the_Copulation_article_exist.3F --Philcha (talk) 12:05, 9 April 2011 (UTC) ...
... and the females mentally and physically become receptive to copulation. It is only during estrus that copulation will result in ... CopulationEdit. "Copulatory tie" redirects here. For copulatory tying in non-canine animals, see Fossa (animal) § Breeding, ... As with most tetrapods, canine copulation involves the male mounting the female from behind, a position that is referred to as ... Virgin dogs can become quite distressed at finding themselves unable to separate during their first copulation, and may try to ...
best medicine to enhance copulation time alongwith their cost in india. how long the medicines to be used? what is the minimum ... best medicine to enhance copulation time alongwith their cost in india. how long the medicines to be used? what is the minimum ... best medicine to enhance copulation time alongwith their cost in india. how long the medicines to be used? what is the minimum ...
  • Join members of Evolution for Everyone ("E4E") to hear a lecture on "Sexual Coercion and Forced In-Pair Copulation as Sperm Competition Tactics in Humans" by Todd Shackelford, Ph.D., Professor and Chair of Psychology at Oakland University. (skepchick.org)
  • During copulation, the clitellum secretes a mucus that keeps the worms paired while sperm are being exchanged. (britannica.com)
  • Despite this, females do seek out extra pair copulations, and, because of the risk, there is more debate about the evolutionary benefits for females. (wikipedia.org)
  • Females fed at the low food level delayed both first copulation and spawning longer than those at higher food levels. (go.jp)
  • 2. Estrus is the next stage, in which estrogen levels are high, mature eggs are released from ovaries, and the females mentally and physically become receptive to copulation . (wikipedia.org)
  • These components are passed to females during copulation and then stored within the spermatheca. (biologists.org)
  • Females, it has become clear, are remarkably promiscuous and have evolved an astonishing array of strategies, employed both before and after copulation, to determine exactly who will father their offspring. (google.ca)
  • Females may lay their eggs immediately or in the months after copulation, and the oviposition strategies seem to be related to the length of the ovipositor. (biomedsearch.com)
  • Investigating the functional morphology of genitalia during copulation in the grasshopper Melanoplus rotundipennis (Scudder, 1878) via correlative microscopy in Journal of Morphology, 278 (2017) 334-359. (kit.edu)
  • However in the male, both neuron and muscle take on modified functions to promote successful copulation. (g3journal.org)
  • As with most tetrapods , canine copulation involves the male mounting the female from behind, a position that is referred to as " doggy style " but does not have a specifically known origin. (wikipedia.org)
  • Unlike human sexual intercourse , where the male penis commonly becomes erect before entering the female, canine copulation involves the male first penetrating the female, after which swelling of the penis to erection occurs, which usually happens rapidly. (wikipedia.org)
  • Copulation, involving a subadult male ring-necked parakeet. (cabi.org)
  • 1. The male organ of copulation in higher vertebrates. (thefreedictionary.com)
  • the male organ of copulation and, in mammals, of urinary excretion. (thefreedictionary.com)
  • The male organ of urination and copulation. (thefreedictionary.com)
  • Copulation is often followed by a period of mate guarding in which the female is held or constantly touched by the male (see table 12.1 in Machado & Macias-Ordonez 2007). (biomedsearch.com)
  • In this paper, we investigate the reproductive behavior of the gonyleptid Chavesincola inexpectabilis Soares & Soares 1946 (Heteropachylinae) and provide basic descriptive information about courtship, copulation, oviposition, and paternal care. (biomedsearch.com)
  • Across the animal kingdom, extra-pair copulation is common in monogamous species, and only a very few pair-bonded species are thought to be exclusively sexually monogamous. (wikipedia.org)
  • Copulation has been directly observed in captive settings for several species of elasmobranchs in large aquaria, and in the wild for three species of urolophids and for Triaenodon obesus and Ginglymostoma cirratum . (springer.com)
  • We discuss the possible issues that led to the extra group copulation . (bvsalud.org)
  • Nevertheless, extra group copulation (EGC) was only reported in A. pigra (Horwich, 1983), A. seniculus (Agoramoorthy & Hsu, 2000), A. guariba (Fialho & Setz, 2007) and A. caraya (Kowaleski et al. (bvsalud.org)
  • extra-pair copulation occurs when one of these individuals mates outside of this pairing. (wikipedia.org)
  • extra-pair copulations produce a greater cost because they put the resources that their mate can offer at risk by copulating outside the relationship. (wikipedia.org)
  • Extra-pair copulation in men has been explained as being partly due to parental investment. (wikipedia.org)
  • This may therefore lead to more extra-pair copulation in men, as they are able to copulate with other women without the consequences of having to rear new offspring. (wikipedia.org)
  • Therefore, extra-pair copulations have a greater cost for women because they put the support and resources that their mate can offer at risk by copulating outside the relationship. (wikipedia.org)
  • In one of the latest episodes of 'Wild Sex', I discuss the fact that in certain animals the processes of ovulation and copulation are coupled. (scientificamerican.com)