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PubMed1997

Variation in sperm precedence during mating in male flies, Dryomyza anilis

To understand how individual differences in fertilization success arises in the fly Dryomyza anilisvariation in sperm precedence between and within males was studied. In D. anilisa mating consists of a copulation followed by tapping sequences during which the male taps the external genitalia of the female. These tapping sequences increase last male sperm precedence. Each male in the experiment was repeatedly mated with a set of females. In the first treatment, mating was interrupted after the male had an intromission. In the second treatment, the male was allowed to perform five tapping sequences after an intromission. In the third treatment, the male was allowed to perform an unlimited number of tapping sequences after an intromission until interrupted by female resistance. There were large differences between males in all three treatments as shown by the 95% confidence limits of the mean fertilization success. Repeatabilities of mating time and the number of tapping movements per tapping sequence were high indicating clear differences between males in these components of mating behaviour. Within individual males, the more tappings per sequence, the higher the fertilization success. In matings with an unlimited number of tapping sequences, fertilization success depended on female resistance. Within-male variation in fertilization success was higher in matings with an unlimited number of tapping sequences than in matings interrupted after a copulation. Several components of male mating behaviour thus contribute to the variation in sperm precedence in D. anilisFemale behaviour, in particular, resistance of tapping movements, can also increase variation in sperm precedence.

Journal Article↗

PubMed1998

Multi-male mating and female choice increase offspring growth in the spider Neriene litigiosa (Linyphiidae)

The purpose of this controlled-breeding study was to investigate the viability consequences of female choice and sequential polyandry for offspring in a way that would separate the influences of these two aspects of female sexual behaviour. Female sierra dome spiders, Neriene litigiosa (=Linyphia litigiosa) typically mate two to three times before production of their first batch of eggs, although some females (ca 16%) mate only once. Strong fighters are preferred as first mates and principal sires. Large males that give a vigorous performance during copulatory courtship are preferred as sires among a female's secondary mates. In this study, the number of matings by free-living females was experimentally controlled and the size and copulatory vigour of all the females' mates were recorded. At the end of the breeding season, the females were collected and their broods were obtained in captivity. Randomly chosen subsets of 28 female's offspring were reared under standard conditions during the following spring. The spiderlings were reared for 27 days in the company of siblings under conditions that would encourage the expression of genetic variation in viability, and growth and survivorship were monitored. After controlling for maternal effects (i.e. female size and oviposition date) and variance in feeding opportunities among rearing groups, both mate number and mate size were positively and independently related to offspring growth rates and the size of offspring attained after emergence from the natal cocoon. The results support the hypotheses that the preference for large males yields viability benefits to offspring and that polyandry can augment the benefits of selective mating. Copyright 1998 The Association for the Study of Animal Behaviour.

Journal Article↗

PubMed1999

Age-related mate choice in the wandering albatross.

We studied mate choice in the wandering albatross, Diomedea exulans, using data from 32 years of banding returns in the population of the Crozet Islands. We studied mating choices in a single year, when the Crozet Islands population was male biased (8:5, males:females). Thus, we expected that females might show great flexibility of choice of partners. Because age and experience might influence mate choice, we tested the expectation that females would choose the oldest and most experienced males for pair bonding. Pair bonds usually last until one member of the pair dies (0.3% of the birds 'divorce'), so mate choice should be especially important. We found that the ages of males and females in both displaying and bonded (breeding) pairs were significantly correlated. These age-associated pairings were not a passive phenomenon, but appeared to be due to an active process of selection of mates of similar age. First-time breeders sought mates of similar age, but preferred those with the most experience. Remating, experienced birds whose mates had died did not pair with individuals of significantly similar age, but predominantly paired with other widowed birds that, on average, were also relatively old. Mate fidelity in wandering albatrosses may be due to the cost of finding and bonding with a new mate. Pair bonds, and thus breeding, took an average of 3.2 and 2.3 years to establish, for males and females, respectively. Thus, remating exerts a potential average reproductive cost of about 15% of lifetime reproductive success. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗

PubMed1995

Biology of Ixodes (Pholeoixodes) hexagonus under laboratory conditions. Part II. Effect of mating on feeding and fecundity of females.

The effect of mating on the feeding and fecundity of Ixodes (Pholeoixodes) hexagonus females was studied under controlled laboratory conditions of 22-23 degrees C and 98% relative humidity. The feeding period of mated females was 6-15 days and 11-13 days for unmated females. The mean weight of the engorged mated females was 114.84 +/- 45.89 mg, whereas, that of the engorged unmated females was significantly lower (80.61 +/- 28.84 mg). During the initial slow feeding period, the weight of mated females increased 6.6 times. At the end of the blood feeding, they had increased their initial weight 35.5 times. Unmated females never entered the rapid engorgement phase and up to 12 days of feeding period their mean weight did not increase more than 9.2 times. The pre-oviposition periods of mated and unmated females were 6-15 days and 4-12 days, respectively. The mean of the egg production efficiency was 40.26 +/- 12.47% for mated females and 35.68 +/- 12.2% for unmated females. The mean of the mass conversion efficiency was 73.6 +/- 13.7% for mated females and 66.48 +/- 16.55% for unmated females. Sixty per cent of the eggs deposited by mated females hatched whereas only 1% of the eggs deposited by unmated females hatched. These results indicate that I. hexagonus females possess some predisposition for parthenogenesis and only fertility and not fecundity depends on mating.

Animals↗

PubMed1991

Mating alters topography and content of oxytocin immunoreactivity in male mouse brain.

Sexual stimulation of males has been reported to affect hypothalamic oxytocinergic systems. In the present study we used radioimmunoassays of microdissected forebrain regions and immunocytochemical analysis of Vibratome sections to study the oxytocin systems of naive males, males killed after one mating, and males mated daily with different receptive females for 3 weeks. In males that had mated once, less oxytocin-immunoreactive neurons were observed in the paraventricular (PVN), supraoptic (SON) and periventricular (NPE) nuclei than in naive males. However, after repeated matings, the number of immunoreactive neurons and their staining intensity was increased in these regions. Furthermore, additional oxytocinergic neurons could be found in the lateral subcommissural nucleus, the zona incerta and the ansa lenticularis of repeatedly mated males. Oxytocin-immunoreactive neurons were only occasionally seen in these areas in unmated males or in animals that had been killed after initial mating. Radioimmunoassays of microdissected PVN, SON, NPE and the lateral hypothalamus confirmed the reduction in oxytocin-immunoreactive levels after a first mating by a male and the increase after repeated matings. It is likely that oxytocin secretion into peripheral and portal circulation is stimulated by the endocrine conditions associated with initial mating. These immediate effects may be followed by the activation of synthesis in oxytocin neurons in several sites of the basal forebrain.

Animals↗

PubMed2004

First experimental evidence for female mate choice in a nocturnal primate.

Female mate choice can be hypothesised in most nocturnal primates, since females show a higher investment in their offspring than males. The aim of this experimental study was to investigate if female grey mouse lemurs perform mate choice and whether age, relatedness (to the male), or male advertisement call activity systematically influence their decisions. A two-way mate choice design was developed in which females could choose between two males. Mate choice was deduced from the time spent in proximity to the males and from mating behaviour. During oestrus 12 of 17 females participated actively in the experiment and all of them showed either a significant spatial (n = 11) or behavioural (n = 1) preference for one male. In four cases copulations were observed. The influence of age on female mate choice was not statistically significant. In the cases with copulations, however, females mostly preferred the older male. This might indicate a preference for older age as an indicator of experience, fitness, and/or status. The influence of relatedness on female mate choice could not be definitely clarified. However, results imply a mechanism of kin recognition on the basis of familiarity. In the majority of choices, females preferred the male with higher trill call activity. Since trill call activity correlates with the relative dominance status of males, these results suggest an importance of the male dominance status for female mate choice in grey mouse lemurs. Altogether our findings indicate that females use a complex of different cues to choose their mates.

Age Factors↗

PubMed2006

Assortative mating for cigarette smoking and for alcohol consumption in female Australian twins and their spouses.

BACKGROUND: Non-random mating affects population variation for substance use and dependence. Developmentally, mate selection leading to positive spousal correlations for genetic similarity may result in increased risk for substance use and misuse in offspring. Mate selection varies by cohort and thus, assortative mating in one generation may produce marked changes in rates of substance use in the next. We aim to clarify the mechanisms contributing to spousal similarity for cigarette smoking and alcohol consumption. METHODS: Using data from female twins and their male spouses, we fit univariate and bivariate twin models to examine the contribution of primary assortative mating and reciprocal marital interaction to spousal resemblance for regular cigarette smoking and nicotine dependence, and for regular alcohol use and alcohol dependence. RESULTS: We found that assortative mating significantly influenced regular smoking, regular alcohol use, nicotine dependence and alcohol dependence. The bivariate models for cigarette smoking and alcohol consumption also highlighted the importance of primary assortative mating on all stages of cigarette smoking and alcohol consumption, with additional evidence for assortative mating across the two stages of alcohol consumption. CONCLUSIONS: Women who regularly used, and subsequently were dependent on cigarettes or alcohol were more likely to marry men with similar behaviors. After mate selection had occurred, one partner's cigarette or alcohol involvement did not significantly modify the other partner's involvement with these psychoactive substances.

Alcohol Drinking↗

PubMed1984

Effect of mating on the metabolic activity of the brain and pituitary gland assessed by [14C]2-deoxyglucose in a reflex ovulator, the vole (Microtus agrestis).

The neural pathways involved in reflex ovulation in the vole (Microtus agrestis) have been investigated with the [14C]2-deoxyglucose (2-DG) method. Female voles were injected i.p. with 2-DG and either not mated, sham-mated (mounted by males by vagina was taped) or mated for a period of 45 min after the injection, after which the animals were decapitated. The brain was processed for autoradiography and the relative metabolic activities (rma) of selected areas of the brain and pituitary gland were determined. The plasma separated from trunk blood was assayed for the concentration of luteinizing hormone (LH). The lordosis quotients (LQ) were (mean +/- S.E.M.) 81 +/- 8 (n = 5) in mated compared with 47 +/- 8 (n = 5) in sham-mated voles. The rma of the midbrain central grey (CG) and reticular formation (RF) were significantly greater in mated and sham-mated voles compared with the values in unmated voles. There were no other between-group differences in the rma of the other 28 areas of the brain or pituitary gland studied in spite of the fact the plasma LH concentration in mated voles was 36.9 +/- 9.6 ng NIH-LH-S18/ml compared with undetectable (less than 2.5 ng/ml) values in all the sham-mated and unmated animals. These results show that in the vole increased metabolic activity of the CG and RF is associated with lordosis, but that the reflex release of LH is not accompanied by any significant change in the metabolic activity of the brain or the pituitary gland.

Animals↗

PubMed1983

Specific contact between mating structure membranes observed in conditional fusion-defective Chlamydomonas mutants.

Mating interactions between opposite mating type gametes in Chlamydomonas reinhardi can be conditionally manipulated by the use of mutants which control different stages in this process. Two independently isolated, sex-limited mutants (expressed only in mating type (-) (mt-] gam-10 and gam-11, have been shown to display a temperature-sensitive defect in mating. Gametes of these mutants can agglutinate, signal, and participate in a specific contact between their activated mating structures and the mating structures of wild-type mt+ gametes but are unable to fuse at the restrictive temperature. Studies of these mutants have resulted in a clear demonstration of this mating type-specific interaction between activated mating structures in this organism. This contact is trypsin-sensitive and therefore appears to involve protein. Both this interaction, and the defect in mating structure fusion, can be further analysed using these mutants.

Cell Membrane↗

PubMed1988

Mating of captive thirteen-lined ground squirrels and the annual timing of estrus.

Thirteen-lined ground squirrels (Spermophilus tridecemlineatus) have a single annual mating season in Michigan, beginning shortly after their spring emergence from hibernation. Captive females were studied during a 3-year period to determine relations among time of removal from the coldroom, vaginal estrus, and mating behavior. Following a 7-month period females spent in a coldroom, vaginal lavages were taken daily to monitor changes in estrous condition. Females removed from the coldroom about when free-living animals emerge from hibernation were in vaginal estrus within 24-48 hr and had an initial period of persistent estrus (ca. 3 weeks), followed by briefer (less than 1 week) and more sporadic estrous periods. Females left in the coldroom 3 weeks longer than normal had significantly briefer initial periods of vaginal estrus after being removed from the coldroom. Similarly, virgin Yearlings and virgin 2-Year-Olds had significantly briefer initial periods of estrus than nonvirgin Adults (greater than or equal to 2 years old). In 1985, eight of eight females paired with males mated within the first week after removal from the coldroom and subsequently produced litters. Mated females remained in vaginal diestrus from within a few days of mating until after parturition. In contrast, unmated females remained in prolonged vaginal estrus during this period. Females first paired with males 3 weeks after being taken from the coldroom failed to mate. In 1986, five of six females first paired with males 2 weeks after being removed from the coldroom similarly failed to mate. However, five of six females did mate that were removed from the coldroom 10 days after those in the previously described group and paired with a male 4 days after removal. This first report of reliable mating behavior in captive thirteen-lined ground squirrels should facilitate subsequent analysis of reproductive patterns in this species.

Animals↗

PubMed1989

Anuran mating calling circuits: inhibition by prostaglandin.

Male American toads (Bufo americanus) were induced to mating call in response to electronically simulated, conspecific mating calls. The injection of prostaglandin (PG) F2 alpha caused suppression of mating call answering. Neural correlates of mating calling were triggered by electrical stimulation of the anterior preoptic nucleus in the isolated brainstem of male, Northern leopard frogs (Rana p. pipiens). The addition of PGF2 alpha to the bath completely abolished the correlates of mating calling without changing the correlates of pulmonary respiration. The suppression of mating calling shown here, along with the suppression of release signalling described by Diakow and Nemiroff (1981), supports the hypothesis of a close interrelation between the neural circuits of these two calls. The suppression of the neural correlates of mating calling in an isolated preparation shows a central site of action of the PG. The retention of normal correlates of pulmonary respiration, even after suppression of mating calling correlates, suggests that the generation of mating calling patterns involves the extension and pulsing of the expiratory phase of breathing.

Animals↗

PubMed1989

Reproductive behavior and LH levels of cockatiels (Nymphicus hollandicus) associated with photostimulation, nest-box presentation, and degree of mate access.

To determine the relative contribution of mate access and environmental cues in stimulating egg-laying and plasma luteinizing hormone (LH) secretion in cockatiels (Nymphicus hollandicus), and of mate access on nest-inspection and bowl-formation, mated pairs were permitted different degrees of mate access (full contact, auditory plus visual contact, auditory contact only, or no contact) and sequentially exposed to three environmental conditions (8L:16D without nest-box access for 6 weeks; 15L:9D without nest-box access for 3 weeks; 15L:9D with nest-box access for 3 weeks). The results indicate that a high degree of mate access is essential for the performance of nesting behaviors, since birds allowed no mate access or only auditory mate access were significantly less likely to inspect the nest or form a nest-bowl. Furthermore, pairs permitted no contact, auditory contact only, or auditory and visual contact delayed nest-inspection and bowl-formation and were significantly less likely to lay eggs than pairs with total mate contact. LH levels were significantly elevated only in photostimulated females of pairs of permitted full mate and nest-box access. These results suggest that maximal sexual activity in cockatiels requires an array of behavioral and environmental cues and that a linear relationship exists between extent of social cues and sexual activity.

Animals↗

PubMed1986

Synchronization of estrus in embryo transfer recipients receiving demi-embryos with Syncro-Mate B or estrumate.

One hundred thirty-five crossbred heifers were used to compare the effectiveness of Estrumate and Syncro-Mate B in synchronizing estrus in recipient heifers for transfer of demi-embryos. A higher percentage (P<0.01) of Syncro-Mate B heifers showed estrus within 5 d following treatment than did Estrumate heifers (100.0 vs 85.1%). Demi-embryos were transferred to 41 and 26 heifers treated with Syncro-Mate B and Estrumate, respectively. The pregnancy rate of heifers synchronized with Estrumate was higher (P<0.01) than that of heifers synchronized with Syncro-Mate B (64.3 vs 27.8%). A single blood sample was collected on the day of embryo transfer from all heifers receiving demi-embryos, and progesterone concentration was determined. There were no significant differences in mean serum progesterone concentrations either between heifers synchronized with Syncro-Mate B and Estrumate or between pregnant and open heifers within synchronization treatment. There was no relationship between serum progesterone concentration and pregnancy rate in the Estrumate recipients (P>0.10). However, 25.0% of the Syncro-Mate B recipients had serum progesterone levels <1.00 ng/ml, and these heifers had a lower pregnancy rate (P<0.05) than Syncro-Mate B heifers with serum progesterone levels between 1.00 to 3.00 ng/ml. It appears that the Syncro-Mate B heifers with <1.00 ng/ml progesterone had either a delay in corpora lutea function or a continuously reduced concentration of serum progesterone which altered the uterine environment of these heifers and caused the lower pregnancy rate in the Syncro-Mate B group. Based on the large difference in pregnancy rates, Estrumate appears to be a more effective method to synchronize estrus in recipient heifers receiving demi-embryos.

Journal Article↗

PubMed1995

Mating and agonistic behavior produce different patterns of Fos immunolabeling in the male Syrian hamster brain.

Previous work has shown that mating induces the expression of Fos protein within the chemosensory pathways of the male Syrian hamster brain. However, it is not known if this pattern of labeling is specific to mating or the result of social interactions in general. To determine the behavioral specificity of activation within these pathways, Fos immunostaining following mating was compared to that following agonistic behavior. Both mating and agonistic behavior are dependent upon chemosensory cues and gonadal steroids (reviewed in Refs 64, 65) and areas belonging to the olfactory and vomeronasal pathways process chemosensory and hormonal information (reviewed in Ref. 48). The results of this study demonstrate both similarities and differences in brain activation patterns following these two social behaviors. Agonistic behavior increased the number of Fos-immunoreactive neurons within most subdivisions of the medial amygdala, the anteromedial and posterointermediate bed nucleus of the stria terminalis, the ventrolateral septum and the ventral premammillary nucleus of the hypothalamus in a pattern comparable to that observed after mating. This pattern of activation common to mating and agonistic behavior may reflect an increase in an animal's general state of arousal during social interactions. In contrast, although mating and agonistic behavior both activated neurons within the caudal subdivision of the medial nucleus of the amygdala, the anterodorsal level of posteromedial bed nucleus of the stria terminalis and the paraventricular and ventromedial nuclei of the hypothalamus, in these areas either the distribution and/or number of Fos-immunoreactive neurons differed. In addition, agonistic behavior selectively activated neurons within the anterolateral bed nucleus of the stria terminalis, the anterior nucleus of the hypothalamus and the dorsal periaqueductal gray, whereas mating alone activated neurons within the posteroventral level of posteromedial bed nucleus of the stria terminalis and the medial preoptic area. No differences were found between dominant and subordinate males following agonistic behavior. These observations along with results from other laboratories suggest that mating and agonistic behavior activate distinct neural circuits.

Aggression↗

PubMed1994

Effects of differential mating stimulation on the onset of prolactin surges in pseudopregnant rats.

In the female rat, stimulation of the uterine cervix (CS) during mating or by artificial means induces daily diurnal and nocturnal surges in prolactin (PRL) secretion which, in the absence of fertilization, result in an 12-day anestrous period called pseudopregnancy (PSP). The amount or type of mating stimulation received by the female during mating determines whether or not PSP occurs, but it has not yet been determined whether different amounts of mating stimulation can alter the time of onset of PRL surges. The present studies examined the latency in days to the first nocturnal PRL surge following mating. Plasma PRL was measured in samples obtained via intra-atrial catheters at 0200-0500h on the day of estrus (Day 0) and on the subsequent 3 days (Days 1-3). In Experiment 1, proestrus females received mating stimulation which was more than (15 intromissions, 15I) or less than (mounts-without-intromission only, MO) sufficient to induce PSP. Surges were absent in 15I females until Days 1-2 and in MO females on all days. In Experiment 2, females received five intromissions (5I) in paced and nonpaced mating tests, types of mating treatments which were expected to induce PSP in some but not all females. PRL surges were not evident at any sampling time in females that continued to cycle, while PRL surges occurred consistently on Day 2 among PSP females. Among PSP females, those receiving 5I showed significantly higher PRL on Day 0 than did 15I females. In both experiments, plasma progesterone concentrations were not higher in PSP than in non-PSP animals until Day 3. In Experiment 3, PRL levels in single samples obtained by cardiac puncture on Day 0 were similar to those seen in the first two experiments. Thus, PRL secretion at the time of the first postmating nocturnal surge is influenced by the type of CS received some 8-10 h earlier. However, if sufficient CS is received to induce the neural changes of PSP, the nocturnal PRL surges are expressed in an all-or-none fashion by 1-2 days after mating.

Animals↗

PubMed2006

Comparison of the effect of natural mating, LH, and GnRH on interval to ovulation and luteal function in llamas.

Gonadotropins and GnRH have been used to electively induce ovulation in llamas and alpacas, but critical evaluation of the natural interval to ovulation after mating has not been performed nor has a direct comparison of the effects of natural mating versus hormone treatments on this interval and subsequent luteal development. The objectives of this study were to compare the effects of hormonal treatments and natural mating on ovulation induction, interval to ovulation, and luteal development in llamas. The ovaries of llamas were examined by transrectal ultrasonography once daily. Llamas with a large follicle were assigned randomly to be: (1) mated with an intact male (mated; n=10); (2) given 5 mg of LH im (LH; n=11); or (3) 50 microg of GnRH im (GnRH; n=10). Ultrasound examinations were performed every 4h from treatment (day 0) to ovulation and thereafter once daily for 15 consecutive days to monitor CL growth and regression (n=5 per group). Plasma progesterone concentrations were measured at days 0, 3, 6, 9, and 12 after treatment to evaluate CL function. The size of the largest preovulatory follicle at the time of treatment did not differ among groups (11+/-0.6, 10.5+/-0.8, 11.8+/-0.9 mm, for mated, LH, and GnRH groups, respectively; P=0.6). No differences were detected among groups (mated, LH, and GnRH) in ovulation rate (80%, 91%, 80%, respectively; P=0.6), or interval from treatment to ovulation (30.0+/-0.5, 29.3+/-0.6, 29.3+/-0.7h, respectively; P=0.9). Similarly, no differences were detected among groups (mated, LH, and GnRH) in maximum CL diameter (14.2+/-0.3, 13.2+/-0.5, and 13.0+/-0.7 mm, respectively; P=0.5), the day of maximum CL diameter (7.6+/-0.2, 7.6+/-0.2, and 7.4+/-0.4 mm, respectively; P=0.6), or the day on which the CL began to regress (12.3+/-0.3 [non-pregnant, n=3], 11.8+/-0.6, 12.2+/-0.4, respectively; P=0.4). The diameter of the CL and plasma progesterone concentrations changed over days (P<0.0001) but the profiles did not differ among groups. In summary, ovulation rate, interval to ovulation, and luteal development were similar among llamas that were mated naturally or treated with LH or GnRH. We conclude that both hormonal preparations are equally reliable for inducing ovulation and suitable for synchronization for artificial insemination or embryo transfer program.

Animals↗

PubMed2005

The costs and benefits of high early mating rates in male stalk-eyed flies, Cyrtodiopsis dalmanni.

Cyrtodiopsis dalmanni stalk-eyed flies have extremely high mating rates. In this paper, we examine the fitness costs and benefits of high mating rates, using flies with low or high early mating rates. We show that high early mating rates are beneficial as they increase the total number of matings gained by a male for a given lifespan. However, males with high early mating rates suffer a cost through lowered survival. There was no consistent effect of male mating rate on female egg production or on male fertility. As higher mating rates are associated with larger accessory gland size, we hypothesize that the extra production of accessory gland products in high early mating males is responsible for much of the cost of reduced longevity.

Animals↗

PubMed2005

Mating activates estrogen receptor-containing neurons in the female monkey brain.

In contrast to some other species, the numbers of activated neurons in the brains of male and female macaques are high in both mated and unmated animals. Dual labeling with the 1D5 anti-estrogen receptor antibody and the c-fos [4] [corrected] polyclonal anti-c-fos antibody was used in 19 female cynomolgus monkeys to examine whether mating selectively increases the activation of neurons containing estrogen receptors (ER). Mated females, and social controls exposed to males without mating, were euthanized about 75 min after the start of the test, exactly 60 min after the first ejaculation (mated females, N=7) and 75 min after the start of exposure to a male (social controls, N=4). A second control group of unmated females (N=8) remained in their individual cages until euthanasia. Neuronal nuclei containing Fos immunoreactivity (Fos-ir) alone, ER-immunoreactivity (ER-ir) alone, or both Fos-ir and ER-ir, were counted in 8 brain regions, but 2 of these regions contained too few ER-ir neurons to permit analysis. The proportion of ER-ir neurons colocalizing Fos-ir was significantly higher in the preoptic area (P=0.027) and ventromedial hypothalamus (P=0.04) of mated than of control females, suggesting the selective activation of ER-containing neurons by mating in these two brain regions known to be important in the control of female mating. The proportion of Fos-ir neurons not containing ER-ir was significantly lower in the cortical amygdala (P=0.045) of mated than in control females, suggesting a selective deactivation of neurons not containing ER-ir.

Animals↗