Stomach acid secretion in submissive and aggressive rats.

Conducted 4 experiments with 60 female and 162 male Long-Evans rats to determine whether aggressive and submissive behavior are related to either an increase or a decrease in gastric secretion. In Exp I, intruder rats placed in an established male–female colony and attacked by a dominant alpha male secreted less acid than intruders exposed to nonaggressive males and females. In Exp II, intruders exposed to attack and subsequently returned to the encounter site, but protected from physical attack, still demonstrated a gastric hyposecretion. Ss with chronic gastric cannulas in Exp III also revealed an acid inhibition when attacked and later when exposed to, but protected from, attack. Both intruders and attacking males were prepared with gastric cannulas in Exp IV. Both demonstrated secretory inhibition following attack and attack-protected sessions. The inhibitory effect was greater and more persistent for intruders than for aggressive Ss. It is suggested that the inhibition occurring during the attack-protected sessions may have been mediated by some conditioning processes, and other possible associative mechanisms, including a learning model or a direct sensory model, are discussed. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experiential determinants of postpartum aggression in mice.

Explored the experiential determinants and the social controls of postpartum aggression in inbred ICR mice. In Exp I, 7 lactating females were tested repeatedly from Day 2 to Day 22 postpartum against male mice; attacks by the females continued through Day 18. Two other groups of 7 females tested only once showed diminished attacks against males by Day 14 postpartum. In Exp II, 8 females were paired with a male for 1 wk prior to parturition; they showed reliably fewer attacks on Day 2 postpartum than a group of 9 females that were isolated prior to parturition. All of these results were obtained in a standard 3-min test. A 24-hr test on Day 4 of Exp II revealed that in both groups female attacks dropped to near zero after 30 min. After female attacks declined, males initiated social behavior which occasioned vocalizations by the females. Further, males attacked in 65% of the tests and destroyed the litters of the females in 53% of the tests. The behavior of the male exerted important influences on the structure of extended female–male interactions. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aggression in male mice lacking functional estrogen receptor α.

Estrogen receptor alpha knockout (ERαKO) male mice fail to display sexual behavior. The authors hypothesized that ERαKOs require higher testosterone (T) concentrations than wild-type (WT) males to exhibit copulatory behavior. Increasing T stimulated sexual behavior and preference for females in WT males but failed to do so in ERαKOs. However, T did induce female-directed aggression in ERαKOs. In aggression tests, WT residents selectively attacked T-treated male intruders. ERαKO residents attacked female, T-treated male, and estrogen-treated male intruders equally. Increased access to olfactory cues prior to direct contact reduced overall aggression in ERαKO versus WT males but did not cause ERαKOs to differentially attack male and female opponents. Results suggest that ERα is essential for normal social behavior, perhaps via processing of chemoinvestigatory cues, which are required to discriminate males from females. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Urine marking and maternal aggression of wild female mice in relation to anogenital distance at birth

A series of experiments were conducted with wild house mice to verify the effect of intrauterine position on females' anogenital distance at birth (AGD) and to examine the relationships between a female's AGD, used as a bioassay of androgen exposure during fetal life, and her social behavior and reproductive success in adulthood. Experiment 1 showed that cesarean-delivered females that developed in utero between two males (2 M females) have significantly longer AGD's than females positioned between two females (0 M females). We then categorized naturally delivered females shortly after birth as having a long, medium or short AGD. In adulthood, these females were tested for their behavior towards unfamiliar pups, their rate of urine-marking in response to a variety of social stimuli, postpartum aggression and success in protecting their litters in response to male and female intruders. Adult females with different AGD's at birth did not differ either in their behavior toward pups or in their rate of urine marking. Conversely, males housed across a wire mesh partition from a long-AGD female deposited a higher number of urine marks than those exposed to a short-AGD female. When tested after delivering a litter, long-AGD females displayed more tail-rattling (a component of agonistic behavior) towards intruders of both sexes in comparison to short-AGD females. These results are consistent with the hypothesis that females with a long AGD are exposed to higher levels of Testosterone during fetal life than females with a short AGD. Although not related to AGD, other measures of maternal aggression were affected by postpartum day, sex of intruders and a female's infanticidal potential while a virgin.     

Male-produced ultrasonic vocalizations and mating patterns in female rats.

Investigated the influence of male-produced 50-kHz vocalizations on mating behavior and choice of partner in estrous female rats. In Exp I, 17 estrous female Long-Evans rats were given a mating-choice test; 2 tethered males, one of which was devocalized, were used as incentives. Darting was directed toward the vocalizing male more frequently than toward the muted test partner, but ultrasonic vocalizations had no influence on visit rate or the amount of time that the females spent with each male. When 2 intact or 2 muted males were used as stimulus objects, the females' solicitation behavior was more evenly distributed between the 2 males. In Exp II, 16 estrous females were given a mating-choice test between 2 muted males; tape-recorded 50-kHz vocalizations or tape hiss was transmitted from a speaker located behind one of the males. Females spent equal amounts of time with the tethered males in both the vocalization and tape-hiss conditions; however, females directed more darting toward the males that were tethered in front of the speaker transmitting the ultrasonic vocalizations than toward the other muted tethered males. Findings demonstrate that the principal function of the male-produced ultrasounds is to facilitate and orient the solicitation behavior of the estrous female during mating. The vocalizations have little demonstrable effect in attracting the female to the immediate physical proximity of the male. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Eating, weight, and dieting disturbances in male and female lightweight and heavyweight rowers

Rowers compete in a sport that allows comparison of male and female athletes and where some (lightweight) but not others (heavyweights) must meet specific weight criteria. Eating attitudes, dieting patterns, weight fluctuation, and methods of weight loss were evaluated in 162 rowers: 82 heavyweights (56 females, 26 males) and 80 lightweights (17 females, 63 males). Females displayed more disturbed eating practices and weight control methods than did males. Lightweights did not have more disturbed eating practices than heavyweights, but employed more extreme weight loss methods. Male rowers were more affected by weight restriction than were female rowers. Lightweight males showed greater weight fluctuation during the season and gained more weight during the offseason than did lightweight females and heavyweight males and females. These results indicate that rowing can join the growing list of sports where eating and weight disturbances may be present. Male athletes may be more vulnerable to these problems than previously recognized.     

Consort bonding and operant behavior by female rhesus monkeys.

An operant conditioning situation was used to relate the leverpressing performance of female rhesus monkeys to different measures of social, sexual, and agonistic behavior that underlie the formation and dissolution of consort bonds. Nine females were trained to press a lever 250 times to gain access to a male partner. After access, a standard 60-min behavioral test took place (1,440 tests). Data were analyzed independently of the stage of the menstrual cycle. Eight females were tested with 2 males, and every female gained access faster with 1 male (i.e, preferred partner). For all 8 females, the preferred male was the one that spent more time grooming the female. For 5 females, the preferred partner was also the one that ejaculated more frequently. For 4 females, where agonistic interactions with males could be evaluated, the preferred male was the one that elicited fewer submissive behavioral patterns. These results indicate that the operant behavior of female rhesus monkeys is positively reinforced by social and sexual factors and negatively reinforced by agonistic interactions and may thus provide a measure of the strength of consort bonds. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Female-enhanced aggression in male rats: Effects of genital anesthesia, castration, or preoptic lesions.

Male rats that had cohabited with ovariectomized females for 2 weeks became more aggressive toward male intruders after a novel estrous female had been placed in their home cages for a period of 4 hr on the previous day. No increase in aggression was seen in males exposed to anestrous females. Genital anesthesia did not attenuate the female-enhanced aggression effect. By contrast, no enhancement of aggression was observed in long-term castrated males after 24 hr of exposure to estrous females. Rats with bilateral electrolytic lesions in the medial preoptic area showed a normal female-enhanced aggression effect. The observations that exposure to females facilitates aggression in males subjected to genital anesthesia and in males with preoptic lesions raise the possibility that copulatory cues are not always required for the effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Harderian gland exudates in the male Meriones unguiculatus regulate female proceptive behavior, aggression, and investigation.

Replicated an earlier finding by the present authors (see record 1986-08500-001) that female proceptive behaviors toward Harderianectomized males are diminished. In the present study, it was shown that estrous females directed fewer proceptive acts toward males lacking Harderian glands. In addition, it was found that females were more defensively aggressive toward Harderianectomized males and preferred to spend more time in the vicinity of intact males. It is speculated that Harderian spread allows the female to assess the reproductive competence of the male. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Responses of male hamsters to odors of females in different reproductive states.

Six experiments investigated the responses of male hamsters to the odors of estrous, diestrous, pregnant, and lactating hamsters. Scent-marking by males in the soiled cages of females was less frequent when the females were estrous (Day 1 of the cycle) than when females were on Days 2, 3, or 4. Sexually experienced males preferred the odors of bedding material from the cages of estrous Ss over odors of bedding of diestrous Ss. Both of these effects were eliminated by surgically removing the vagina and thereby eliminating vaginal secretions. The quantity of vaginal secretions deposited in the vicinity of the nest may be responsible for the observed effects. In contrast, neither males with sexual experience nor males with both sexual and nonsexual experience with females demonstrated preferences for the odors of the estrous or diestrous Ss themselves. Males were, however, more attracted to the odors emanating directly from estrous Ss than to the odors of pregnant or lactating Ss. For hamsters the important sexual message may be not "estrous" vs "diestrous" but rather may be "will soon be estrous" (i.e., cycling) vs "not soon estrous" (i.e., pregnant, lactating, or acyclic). (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Male and female estimates of personal problems of men and women.

100 male and 100 female undergraduates estimated the types of problems males and females would present at a counseling center. Of 75 problems on a problem checklist, 35 problems were seen as being more typically female whereas only 16 were seen as being more typically male. Sex differences in estimates were found for 13 problems; however, these differences did not affect whether the problems were seen as male or female. Of the 16 male problems, 8 were vocational-educational problems, while none of the female problems was vocational-educational. A 2nd purpose of the study was to look at sex differences in problems presented by actual clients at a university counseling center. Of the 75 problems on the checklist, sex differences were found for only 3 problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Odor preferences of female house mice (Mus domesticus) in seminatural enclosures.

Preferences for male odors by female house mice (Mus domesticus) were examined with respect to age, dominance status, and spatial relationships. Mice were free living in 6 field enclosures. Estrous or nonestrous females were placed in an aquarium with soiled bedding from live traps as the odor source. Females were tested for preferences between (1) adult and juvenile male odors, (2) dominant and subordinate male odors, and (3) "near" and "far" male odors. In dominance odor tests, estrous females preferred odors from dominant males; nonestrous females exhibited no significant preferences. In adult juvenile and spatial odor tests, there were no significant differences between odor preferences of estrous and nonestrous females. However, most females preferred odors from adult and "near" males. Male dominance status appears to be the strongest influence on female odor preference in these seminatural enclosures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Context-dependent acquisition of copulatory behavior in the male rat: Role of female availability.

The effect of the environment in which sexual experience is acquired was examined on patterns of male rat copulatory behavior. Males trained in a pacing chamber with a 4-hole partition had significantly shorter ejaculation latencies compared with males trained in chambers with a 1-hole partition. Those differences persisted when males were switched into the other pacing condition, suggesting that the pattern of copulation in these males had become "fixed." In the second experiment, males were trained to associate an almond odor with copulation in either the 1-hole or 4-hole condition. Males ejaculated preferentially with females associated with the 4-hole pacing condition. Copulatory behavior in male rats is sensitive to female availability, and females associated with greater availability are preferred. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attitudes towards homosexuality and male and female reactions to homosexual and heterosexual slides.

Investigated the relationship between attitudes toward male and female homosexuality and Ss' reactions to slides of various explicit sexual activities (including homosexuality, lesbianism, heterosexual activity, and group sex). Attitudes toward homosexuality and lesbianism were highly correlated. Saskatchewan males were more antihomosexual than an Ontario sample, supporting the suggestion that there is greater concern with "machismo" among males on the Prairies. 34 male and 31 female undergraduates were divided into those opposed to homosexuality (anti-H) and those not opposed (H-neutral) on the basis of attitude scale scores. While the 4 groups substantially agreed in the relative rating of the slides, anti-H Ss of both sexes rated the slides as more pornographic and evaluated them more negatively than H-neutral Ss. Females rated them more negatively than males, while males rated all but the male themes (male nude, masturbation, homosexual) more sexually arousing than did females. Males reacted more negatively to the male themes than to the comparable female themes. Female Ss showed no such difference. (French summary) (1 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Paternal behavior in the male Long-Evans rat (Rattus norvegicus).

Five studies examined the paternal behavior of monogamously housed male and female, individually housed male, and virgin male and female Long-Evans rats. Findings indicate that males cohabiting monogamously with females showed low levels of pup contact and parental behavior, and the frequency of these behaviors did not increase with experience, possibly because the lactating females kept the males away from the pups. When presented with pups in their own cage, sexually experienced and naive males did not differ in the latency or frequency of parental behavior, and both groups showed more parental behavior than monogamously housed males. Males that had formerly exhibited infanticide showed as much parental behavior as noninfanticidal males. The frequency of pup contact and parental behavior increased as the pups grew older. Although virgin males showed the same latency as virgin females to exhibit parental behaviors, females showed these behaviors more frequently than males. Results suggest that the responsiveness of noninfanticidal male rats to infants may depend on the test situation and the age of the infants. (45 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

cDNA cloning, sequencing, and characterization of male and female rat liver aldehyde oxidase (rAOX1). Differences in redox status may distinguish male and female forms of hepatic APX

Molecular characterization of male and female rat liver aldehyde oxidase is reported. As described for the mouse liver, male and female rat liver expressed kinetically distinct forms of aldehyde oxidase. Our data suggest that the two forms arise as a result of differences in redox state and are most simply explained by expression of a single gene encoding aldehyde oxidase in rats. In support of this argument we have sequenced cDNAs from male and female rat liver. We examined mRNA expression by Northern blot analysis with RNA from males and females, from several tissues, and following androgen induction. Purified rat liver enzyme from males or females revealed a single 150-kDa species consistent with cDNA sequence analysis. Both male and female forms were reactive to the same carboxyl-terminal directed antisera. Km(app) values obtained in crude extracts of male or female rat liver and post-benzamidine-purified aldehyde oxidase differed substantially from each other but could be interconverted by chemical reduction with dithiothreitol or oxidation with 4,4'-dithiodipyridine. Our data indicate that a single gene is most likely expressed in male or female rat liver and that the kinetic differences between male and female rat liver aldehyde oxidases are sensitive to redox manipulation.     

Differential responses to male and female depressive reactions.

Suggests that the commonly reported preponderance of female over male depression in incidence and prevalence studies requires further analysis. One explanation is that the social consequences of expression of depressive symptomatology are different for males and females. A comparison of 157 male and 189 female undergraduates' reactions to male and female case histories of common reactions to stress confirmed the hypothesis. Depression elicited more rejection of males than of females, and the sex difference in rejection of depression was more pronounced than for anxiety or flat affect-detached responses. A discriminant analysis suggested that depressed males are especially likely to be perceived as impaired in role functioning as compared with depressed females. Results suggest that depressed males are not rejected for expression of emotionality as such. Speculations about the causes and consequences of differential rejection of depression are noted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assortative mating and female clutch investment in black grouse

Variation in female behaviour has only recently received attention in studies of sexual selection. It has been suggested that females may invest differentially in their offspring in relation to the quality of their mate. This may lead to females that mate with high-quality and/or attractive males laying larger clutches. Females may also differ in their ability to choose between males. For example, females in good physical condition may make better choices. If physical condition and clutch size are positively correlated, this hypothesis could also produce a relationship between male attractiveness and female clutch size. We found, in lekking black grouse, Tetrao tetrix, that females mated to the highest ranked males laid the largest clutches. Furthermore we found, regardless of female age, a positive relationship between a measure of female condition and male rank but not between female condition and her clutch size. In addition, females in good condition visited a larger number of different male territories, and old females produced the largest clutches. Our results suggest two mechanisms to explain our findings. First, females in good physical condition tend to mate with the top males, suggesting an assortative mating pattern. Second, females mating with the highest ranked males lay larger clutches as a consequence of their choice. In general, our result calls for caution in evaluating studies that look at the consequences of mate choice. It may be that differences in female quality produce effects that may be wrongly interpreted as male quality effects. (c) 1998 The Association for the Study of Animal Behaviour.     

Receptivity of the female rat (Rattus norvegicus) after male devocalization: A ventral perspective.

Male rats (Rattus norvegicus) emit at least two patterns of vocalization during copulation, the mating call and the pre-ejaculatory call. Both calls promote immobility of the female during lordosis, but the pre-ejaculatory calls are more effective. We undertook, through ventral observations of the mating pair, to determine if the female failed to assume or maintain the lordosis posture when mounted by a devocalized male and also to determine if the devocalized male was providing adequate stimulation to induce receptive behavior. Females were more likely to move away from the devocalized males before assuming the full lordosis posture. Furthermore, they were more likely to move away before the males had a chance to engage in intromissive behavior. However, when the females remained immobile along enough for the males to achieve a mount or intromission, there was little difference in the behavior of either animal that resulted from the devocalization of the male. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavior of attack-primed and attack-satiated female golden hamsters (Mesocricetus auratus).

In 3 experiments with 50 female hamsters, "priming" the S by allowing it one biting attack on a smaller, methotrimeprazine-treated target hamster significantly decreased its latency to attack a subsequently presented probe target. Conversely, the latency of attacks on the probe was increased, and the number of attacks decreased, if the S was first "satiated" by allowing it 1 hr of ad-lib access to a target followed by a series of briefer target presentations until a criterion of 3 successive presentations without attack was met. The respective aggression-increasing and aggression-decreasing effects of these manipulations were also demonstrated in more naturalistic, unrestrained encounters between pairs of Ss that had just been exposed to the same manipulation. Neither manipulation affected the nonaggressive behaviors of sunflower seed acceptance and wheel running, which suggests that the effects of attack priming and satiation may be specific to aggression. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)