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PubMed1990

Desire and ability: hormones and the regulation of female sexual behavior.

The distinction between the ability to copulate and the desire to copulate is used to understand species differences in hormonal regulation of female sexual behavior. Evidence is presented demonstrating that ovarian hormones modulate female sexual motivation in both rodent and primate females. The thesis is developed that rodent females differ from primate females primarily in their dependence upon hormones for the ability to mate. Thus, apparent differences between the two groups of females in the extent to which hormones control copulatory behavior does not stem from differences in hormonal regulation of female sexual motivation but from the physical ability of primate, but not rodent, females to mate without hormonal stimulation. This emancipation of the ability to copulate from hormonal influence makes female sexual motivation the primary regulator of mating in primates. Dependence upon female sexual motivation means that the copulatory behavior of primate females is easily influenced by their physical and social environment. Because primate females can mate without hormonal input, female sexual initiation, not copulation, is argued to be the only valid indicator of female sexual motivation.

Animals↗
PubMed1999

Performance of appetitive or consummatory components of male sexual behavior is mediated by different brain areas: a 2-deoxyglucose autoradiographic study.

The in vivo autoradiographic deoxyglucose method was used to identify the functional brain circuits that are involved in the performance of appetitive and consummatory components of male sexual behavior in Japanese quail (Coturnix japonica). Two groups of castrated, testosterone-treated male quail were trained during 12 sessions to associate the view of a female behind a window with the opportunity to interact freely and to copulate with her. They developed, as a consequence, a social proximity response (staying close and looking through the window providing a view of the female) that has been used in previous experiments to measure appetitive sexual behavior. A third control group (also castrated and treated with testosterone) was allowed to view the female but not to copulate with her and therefore did not develop this proximity response. 2-14C-deoxyglucose was then injected i.p. to these birds and they were allowed to either copulate freely with a female (consummatory sexual behavior group) or express the social proximity response (appetitive sexual behavior group). The control group was provided a view of the female but these birds, although they were exposed to the same stimuli as birds in the appetitive group, did not express the social proximity response because they had never learned the association with the opportunity to copulate. Birds were killed 45 min after the deoxyglucose injection and their brains were processed for autoradiography. Densitometric analyses of the autoradiograms revealed that the expression of appetitive or consummatory aspects of male sexual behavior was associated with significant increases by comparison with the control group in the deoxyglucose incorporation in the nucleus mesencephalicus lateralis, pars dorsalis and in the nucleus leminsci lateralis. In addition, an increase in the deoxyglucose incorporation was specifically observed in the paleostriatum primitivum, rostral preoptic area, nucleus intercollicularis, nucleus interpeduncularis and third nerve but a decrease was observed in the dorsomedial part of the hippocampus and in the nucleus nervi oculomotori in birds of the consummatory sexual behavior group by comparison with controls. By contrast, in the appetitive sexual behavior group, significant increases in deoxyglucose incorporation were observed in two telencephalic areas, the intermediate hyperstriatum ventrale and neostriatum caudolaterale by comparison with the controls, but decreases were detected in the stratum griseum et fibrosum superficiale of optic tectum by comparison with the consummatory behavior group. These studies demonstrate that the performance of appetitive or consummatory components of male sexual behavior affects in a specific manner the deoxyglucose uptake and accumulation in specific regions of the quail brain. Changes in metabolic activity were observed in steroid-sensitive areas, in auditory, visual and vocal brain regions, and in brain nuclei related to motor behavior but also in association telencephalic and limbic structures. These changes in oxidative metabolism overlap to some extent with metabolic changes as revealed by immunocytochemistry for the immediate early gene products Fos and Zenk, but many specific reactions are also detected indicating that these techniques are not necessarily redundant and, together, they can provide a more complete picture of the brain circuits that are implicated in the control and performance of complex behaviors.

Animals↗
PubMed1994

Stimulus control of copulatory behavior in sexually naive male Japanese quail (Coturnix japonica): effects of test context and stimulus movement.

Sexually experienced male quail (Coturnix japonica) are more likely to engage in copulatory behavior than sexually naive ones. These experiments suggest that sexual experience in a particular place may facilitate later copulatory responding because of increased familiarity with the contextual cues of the environment. Male quail in Experiment 1 did not copulate reliably with taxidermic models of females in a novel context, even though some of the subjects were allowed to copulate with female quail in their home cages. In contrast, sexually naive males in Experiments 2 and 3 copulated vigorously with taxidermic models of females in a familiar context. In Experiment 4, sexually naive males tested in an unfamiliar context were more likely to copulate with a moving than with a static model. The stimulus control of copulatory behavior in sexually naive male quail was similar to that in sexually experienced ones but only in familiar contexts.

Animals↗
PubMed1997

Induction of the Zenk protein after sexual interactions in male Japanese quail.

We mapped cells immunoreactive (ir) for the protein encoded by the immediate early gene zenk in the brains of male Japanese quail after they engaged in either appetitive or consummatory sexual behavior (i.e. copulation). Castrated males treated with testosterone were either allowed to copulate with a female or exhibited a learned social proximity response indicative of appetitive sexual behavior, and were compared with control males in their home cage or in the experimental chamber but not exhibiting the proximity response. Copulation increased the number of ZENK-ir cells in the nucleus striae terminalis and the nucleus intercollicularis, while both copulation and the proximity response induced increases in the medial and anterior ventral hyperstriatum. These results indicate that zenk is induced in the context of sexual behavior.

Analysis of Variance↗
PubMed2004

Female choice of young sperm in a genetically monogamous bird.

When females copulate with multiple males the potential exists for female sperm choice. Females may increase the probability of being fertilized by preferred males by selectively retaining their sperm while ejecting the sperm of unfavoured males. An alternative criterion to male quality for female sperm choice may be sperm age because old sperm degrade and can lead to zygote death or unhealthy offspring. Here, we report that in a genetically monogamous bird, the black-legged kittiwake Rissa tridactyla, females eject their mates' sperm according to when the copulations were performed. Following copulations that were performed approximately two weeks before egg laying, females ejected inseminations at high frequencies while retaining inseminations that occurred soon before laying. Females that suffered hatching failure had ejected sperm from early copulations less than half as frequently as females whose entire clutches hatched. Furthermore, chicks that hatched from eggs fertilized by old sperm were in poor condition relative to those fertilized by young sperm. These findings support the 'young sperm' hypothesis, which predicts that females choose fresh sperm to avoid reproductive failure and are the first to show intra-male sperm choice by females.

Animals↗
PubMed2001

Cryptic reproductive isolation in the Drosophila simulans species complex.

Forms of reproductive isolation that act after copulation but before fertilization are potentially important components of speciation, but are studied only infrequently. We examined postmating, prezygotic reproductive isolation in three hybridizations within the Drosophila simulans species complex. We allowed females to mate only once, observed and timed all copulations, dissected a subset of the females to track the storage and retention of sperm, examined the number and hatchability of eggs laid after insemination, counted all progeny produced, and measured the longevity of mated females. Each of the three hybridizations is characterized by a different set of cryptic barriers to heterospecific fertilization. When D. simulans females mate with D. sechellia males, few heterospecific sperm are transferred, even during long copulations. In contrast, copulations of D. simulans females with D. mauritiana males are often too short to allow sperm transfer. Those that are long enough to allow insemination, however, involve the transfer of many sperm, but only a fraction of these heterospecific sperm are stored by females, who also lay fewer eggs than do D. simulans females mated with conspecific males. Finally, when D. mauritiana females mate with D. simulans males, sperm are transferred and stored in abundance, but are lost rapidly from the reproductive tract and are therefore used inefficiently. These results add considerably to the list of reproductive isolating mechanisms in this well-studied clade and possibly to the list of evolutionary processes that could contribute to their reproductive isolation.

Animals↗
PubMed2006

Preoptic glutamate facilitates male sexual behavior.

The medial preoptic area (MPOA) is a critical regulatory site for the control of male sexual behavior. We first measured glutamate in 2 min microdialysate samples from the MPOA before, during, and after copulation by male rats. There was a slight [approximately 140% of baseline (BL)] rise in extracellular glutamate when the female was presented, a significant increase (approximately 170% of BL) during periods of mounting and intromitting, and a very large increase in samples collected during ejaculation (approximately 300% of BL). A precipitous fall in levels occurred in the first postejaculatory sample; the magnitude of this fall was highly correlated with the length of the postejaculatory interval of quiescence. In experiment 2, we reverse-dialyzed a mixture of glutamate uptake inhibitors into the MPOA before and during mating; control animals received artificial CSF. The mixture increased extracellular glutamate (approximately 280% of BL), increased the number of ejaculations in the 40 min test, decreased ejaculation latency, and decreased the postejaculatory latency to resume copulation. These data, together with other findings that glutamate in the MPOA can elicit genital reflexes in anesthetized rats and that glutamate receptor antagonists in the MPOA impair copulation, strongly suggest that MPOA glutamate is a major facilitator of copulation and that the postejaculatory fall in glutamate regulates the postejaculatory interval.

Animals↗
PubMed1993

Selection and utilization of spermatozoa in the reproductive tract of the female zebra finch Taeniopygia guttata.

The numbers and proportion of spermatozoa reaching different parts of the female reproductive tract after a single natural insemination were investigated in zebra finches Taeniopygia guttata. The number of spermatozoa transferred during a single, natural copulation was estimated by comparing the number of spermatozoa in the seminal glomera of males that had performed a single copulation with control males. The mean number of spermatozoa per ejaculate was 5.8 x 10(6) +/- 1.80 x 10(6) SEM. The mean number of spermatozoa stored in the sperm storage tubules in the uterovaginal junction following a single, natural insemination was 6027 +/- 1874, 0.104% of those inseminated. The mean number of spermatozoa reaching the infundibulum and trapped on the perivitelline layer of all eggs of the clutch after a single copulation was 45.6 +/- 9.18 and a further 36 penetrated the perivitelline layer of the ovum, i.e. 82 in total (1.4% of the spermatozoa in the sperm storage tubules and 0.001% of spermatozoa in the ejaculate). Female zebra finches that completed a natural breeding cycle with a mean of 12 copulations had 404 +/- 111 spermatozoa trapped on the perivitelline layer of all eggs of the clutch, and an estimated further 173 spermatozoa penetrated the perivitelline layer. A smaller proportion of spermatozoa was trapped on the perivitelline layer of zebra finch eggs, than in chicken or turkey eggs.

Animals↗
PubMed1999

Mating activity and fitness of a few wild type strains of Drosophila ananassae.

Courtship time, duration of copulation and fertility were tested in six wild type strains of D. ananassae originating from different geographical localities. The results indicate that there is significant variation among the strains tested with respect to courtship time, duration of copulation and fertility. The strains showing a longer duration of copulation produce more progeny. These findings suggest that there is a positive correlation between duration of copulation and fertility in D. ananassae.

Animals↗
PubMed2000

[Cell biology and life cycle of the testate amoeba Corythion delamarei].

Corythion delamarei Bonnet, Thomas, 1960, a typical testate amoeba with hyaline, filiform pseudopodia (Filosea Leidy, 1879), is a mass and widely spread species in the forest soil of Leningrad district. This species has been studied in natural and experimental conditions by means of morphological, cytochemical and morphometrical methods, including original culturing in vitro. The complex life cycle of C. delamarei involves the number of phases: trophozoites, precysts, resting cysts, copulating trophozoits, cystozygotes, cells with spores inside the shell, small amoeboid cells producing spores after germination. Different stages display structural peculiarities reflecting adaptation to exogenous environment. In C. delamarei sexual process has been first discovered. It represents a primitive form of isogamic copulation of morphologically similar trophozoites copulation and results in uninuclear cystozygote formation. The zygote nucleus is a synkaryon meiosis is zygotic, and is accomplished in two steps. Copulation occurs only between two trophozoites of one and the same species. Further zygote development includes its excystation that eventually gives rise to a trophozoite which then undergoes several metagamic divisions resulting in spore formation, thus starting a new generation of trophozoites.

Amoeba↗
PubMed1978

[Reflex factors that modify the effect of p-chlorophenylalanine on ovulation and reproduction in rats (author's transl)].

The appearance of reflex ovulation in rats under the influence of the copulation, has been studied. Evaluation of insemination, fecundation, number of embryos, ovarian cycle and ovulation in several groups of rats treated with doses of p-CPA (300 mg/Kg, i.p.), have been made. The application of p-CPA 48 hours before the estrus phase, inhibits the ovulation. This increases significantly through copulation. Reproduction is totally inhibited by p-CPA in animals under copulation conditions during 24 hours of the estrus phase. The inhibition is desappears if placed under copulation conditions during a full cycle. Inseminated rats had a 33% decrease in number of embryos with respect to the control group. The application op-CPA 24 hours before the estrus phase does not produce any inhibition effect. The decrease observed in the number of embryos is non-significant. When p-CPA is applied, instead, 48 hours before the estrus phase, there is total inhibition of the reproductive conduct.

Animals↗
PubMedDate not supplied

[The evolution of forms of hermaphroditism in Cyclophyllidea (Cestoda). 1. Morpho-functional causes of the formation of tapeworms with the protandrous type of genital apparatus development].

Morpho-fuctional causes of the formation of protandrous Cyclophyllidea (tapeworms) have been studied. Two forms of protandry are described. The protandry type I is typical for polymeric (polysegmental) Hymenolepididae. It appears independently in different taxa of this family (Aploparaksis, Echinatrium, Wardium, Diorchis and others) while the narrow-strobila forms with a low prolificacy of proglottids are formed. The development of this living form of hymenolepidids is ecologically caused by the high density of their aggregation in intestines of hosts. The primordium results in the development of genitals in the juvenile strobila proglottids with the limited internal space. Due to this process, parallel morphogenesis of male and female gonads is proved to be impossible. A selection leading to the overtaking development of testicles and copulative apparatus regarding morphogenesis of ovary and vitellarium is based an earlier maturation of testicles and group copulation of proglottids with and underdeveloped ovary that is typical in original euandrogyne forms. The group insemination of proglottids from a polysegmented strobila reduces the number of copulation and improves an efficiency of cross-copulation of tapeworms and. As a result, morpho-functional zones of male proglottids characterized by an immature ovary and those of fertile female segments losing their testicles are differentiated in the strobila. The protandry type II is typical of mesomeric tapeworms (Dilepididae, Schistotaeniidae, Anoplocephalidae). It is also resulted from a limited space of proglottids for developing the hermaphroditic genital apparatus. This is caused by the shift of genital morphogenesis process into juvenile proglottids and also by the enlargement of gonad sizes as the result of a selection for a higher prolificacy of proglottids. The dissociation of the development of male and female gonads takes place because of the retardation of ovary morphogenesis.

Animals↗
PubMed2006

Social status and availability of females determine patterns of sperm allocation in the fowl.

Where sperm competition occurs, the number and quality of sperm males inseminate relative to rival males influences fertilization success. The number of sperm males produce, however, is limited, and theoretically males should allocate sperm according to the probability of gaining future reproductive opportunities and the reproductive benefits associated with copulations. However, the reproductive opportunities and value of copulations males obtain can change over their lifetime, but whether individuals respond to such changes by adjusting the way they allocate sperm is unclear. Here we show that, in the fowl, Gallus gallus, dominant males, which have preferential access to females, modulate the number of sperm they ejaculate according to the availability of females. When presented with two females, dominant males allocated more sperm to higher quality females, whereas when females were on their own, only copulation order had an affect on their sperm numbers. In contrast, subordinate males, whose mating activity is restricted by dominant males, allocated high numbers of sperm to initial copulations, irrespective of female availability. We further show, by manipulating male social status, that sperm allocation is both phenotypically plastic, with males adjusting their patterns of sperm allocation according to their dominance rank, and intrinsic, with males being consistently different in the way they allocate sperm, once the effects of social status are taken into account. This study suggests that males have evolved sophisticated patterns of sperm allocation to respond to frequent fluctuations in the value and frequency of reproductive opportunities.

Animals↗
PubMed1980

Reproductive physiology and behaviour of gorillas.

Research on reproduction of gorillas focussed on 3 related issues, cyclicity in sexual behaviour, hormonal regulation of sexual behaviour and restriction of mating to the periovulatory phase of the menstrual cycle. A study of female genital swelling or perineal labial tumescence demonstrated that this tumescence exhibited a pattern that was similar to that of the female chimpanzee, although maximal tumescence was for only 1-2 days of the 32-day cycle. Female gorillas were the initiators of sexual activity and copulation was restricted to a relatively brief, 1-2 day period, associated with maximal or near-maximal labial tumescence. Gorillas exhibited menstrual cycle hormone patterns more similar in certain respects to the chimpanzee and human than to other primates. Labial tumescence increased with increasing concentrations of oestradiol-17 beta during the follicular phase and detumescence occurred after the midcycle surge in LH at the time oestradiol was declining and progesterone was increasing. Sexual behaviour of individual gorillas was not restricted to the time of the midcycle peaks in oestradiol-17 beta or testosterone. The pattern for the entire group, however, indicated increased copulation with increasing oestradiol values and a maximal frequency of copulation on the day of the testosterone peak. When females controlled mating, copulation occurred primarily during the periovulatory period, whereas mating temporally dissociated from the periovulatory period seemed to result from the male's intimidation of the female. The data suggest that hormones exert a significant influence on the regulation of sexual behaviour by gorillas, but that environmental and social factors can moderate that influence.

Animals↗
PubMed2004

Hormone profiles and reproductive characteristics in wild female Japanese macaques (Macaca fuscata).

In this study we investigated the reproductive characteristics of wild female Japanese macaques (Macaca fuscata fuscata) in 2 nonconsecutive years using noninvasive methods to monitor physiological events. We detected ovulation dates and ascertained conceptions from fecal hormone profiles. First ovulations occurred from middle October to early November in 1997, and from middle to late November in 1999. Most females conceived during their first ovarian cycle. On average, postconception bleeding occurred 18.4 days after ovulation, and menstruation occurred 13.7 days after ovulation. The average gestation length was 176.3 days. The average degree of facial redness and the percentage of females that copulated synchronously changed across the ovarian cycle and peaked in the periovulatory period. Although prolonged periods of postconception copulation have been reported in previous studies, they did not occur in this study, which suggests that such behavior may not be a species-typical characteristic. Female fertility varied between the 2 years. The copulation rates of females with no infant <1 year of age were 100% (14/14) in 1997 and 45.5% (5/11) in 1999. The ovulation rates of the female subjects that we chose for hormonal assays were 100% (9/9) in 1997 and 50.0% (3/6) in 1999. Th conception rates of these selected females were 100% (9/9) in 1997 and 16.7% (1/6) in 1999. The birth rates (the number of females that delivered divided by the total number of adult females in the troop) were 73.3% (11/15) in 1998 and 6.7% (1/15) in 2000. The modified birth rates (the number of females that delivered /the number of adult females with no infant <1 year of age) x 100 were 78.6% (11/14) in 1998 and 9.1% (1/11) in 2000.

Animals↗
PubMed2002

Spermatophore transfer in the hermit crab Clibanarius vittatus (Crustacea, Anomura, Diogenidae).

Although mating has been described in several hermit crab species, the mechanics of spermatophore transfer have not previously been demonstrated. Evidence from pleopod and gonopore morphology, video observations, and inseminated females indicates that in Clibanarius vittatus the male applies a spermatophoric mass directly onto the female via the gonopores rather than with modified pleopods 1-2 (gonopods) and/or genital papillae as in many other decapods. The single second pleopod of males of C. vittatus has a simple endopod with no apparent modifications for sperm transfer. There are no genital papillae extending from the male gonopores. The globular spermatophores are aligned in rows surrounded by a seminal secretion in the male ducts (vasa deferentia that terminate in ejaculatory ducts opening to the exterior via the gonopores). During copulation, described from time-lapse video recordings, the ventral surface of the last thoracic segment of the male, bearing the gonopores, was apposed to the ventral cephalothorax of the female. A massive amount of seminal secretion containing spermatophore ribbons, termed here the spermatophoric mass and described for the first time in a hermit crab species, was observed covering the sternites and coxae of pereopods 1-5 of a recently copulated female. It is suggested that during copulation the male emits the contents of the ejaculatory ducts directly onto the female without the aid of gonopods or genital papillae. Although spermatophore transfer is simple in C. vittatus, the presence of modified anterior pleopods or elongate genital papillae (sexual tubes) in other paguroidean species suggests the possibility of a more complex insemination process in these other hermit crabs.

Animals↗
PubMed1993

Breeding cycles and fecal gonadal steroids in the brown dipper Cinclus pallasii.

Breeding cycles and fecal gonadal steroids were investigated in free-living brown dippers, Cinclus pallasii. The brown dippers were marked with colored leg bands, and their behavior was observed by a field scope. The breeding season was divided into six stages according to the behavior observed; winter territory-defending, nest-building, copulation, incubation, nestling, and fledgling stages. Fecal pellets on the stones in their territories were collected and the levels of immunoreactive estradiol-17 beta (E2) and testosterone (T) in 10 mg feces were measured by radioimmunoassay. Levels of fecal E2 were high only during the copulation stage, which lasted for a few weeks, in all females of the three pairs observed. In contrast, T levels in the feces of males increased in late winter when intensive territory-defending behavior was observed, and remained high until the end of the breeding season. T levels during the nest-building stage and the copulation stage were similar to those during other nesting stages. When the birds breed only once a year, the duration of high levels of T was shorter than that of the pair with the second clutch. T levels in the feces of females showed a similar pattern to E2 levels.

Animals↗
PubMed2002

Androgen implants in medial amygdala briefly maintain noncontact erection in castrated male rats.

Castration of male rats causes a rapid loss of their normal erectile response to inaccessible estrous females. Previous studies had demonstrated that these noncontact erections (NCEs), a putative sign of sexual arousal, could be restored by systemic treatment with testosterone (T) or dihydrotestosterone (DHT), but not estradiol (E). We examined whether androgen delivered to the medial amygdala (MeA) of castrated rats would maintain NCE. In Experiment 1, males received bilateral cannulae filled with T, DHT, or E directed at the MeA. Control males had the same hormone-filled cannulae implanted subcutaneously and blank cannulae in the MeA, or they received T in the anterior forebrain. During the 2 weeks after surgery, males were tested twice for NCE and copulation. About half the males with androgens in the MeA had NCEs 1 week after castration, but few responded a week later. Closer proximity of androgen implants to the posterodorsal MeA (MeApd) predicted shorter NCE latencies. No males with subcutaneous androgen had NCEs in either test, and few anterior forebrain-implanted males did. Some males receiving E in MeA or subcutaneously had NCE in each test. In copulation tests, the type of steroid treatment did not affect the incidence of ejaculation or most measures of copulation, and the proximity of cannulae to MeApd predicted only the time from ejaculation to the occurrence of NCE during the postejaculatory interval. Experiment 2 showed that NCEs displayed by males with androgen in MeA occurred in response to estrous females, not spontaneously. The results suggest that androgens, perhaps augmented by estrogen, act in the posterodorsal MeA to facilitate NCE and its associated arousal.

Amygdala↗