Isolation-induced facilitation of male sexual behavior in mice

Sexual performance of male mice housed individually or in groups of 3 or 12 was compared. Experiment 1 examined naive males presented at weekly intervals with ovariectomized, estrogen-primed, progesterone-treated females. Performance in isolates was consistently superior and reached an asymptote that was twice that of grouped animals. Reversal of housing conditions reversed performance. Experiment 2 varied intervals of isolation among subjects, finding facilitation at several intervals. Experiment 3 compared animals under different population densities. Density did not alter the effects of isolation and grouping. In all experiments, additional tests with target males indicated that aggressive and sexual performance were moderately correlated and responded similarly to parametric manipulations. These results parallel and extend studies of isolation-induced aggression.     

Motivational control of sexual behavior in Aplysia fasciata: sequencing and modulation by sexual deprivation and by addition of partners

Variables similar to those affecting feeding behavior also modulate sexual behavior in Aplysia fasciata, indicating that mating is under motivational control. Motivated behaviors are often patterned into appetitive and consummatory components. Courtship, the appetitive phase of male sexual behavior, was temporally related to subsequent mating. Although many bouts of courtship failed to lead to mating, most incidents of mating were preceded by courtship. Motivation is also characterized by satiation after the goal of the behavior is achieved. We found an increase in likelihood to mate following a period of sexual isolation. Motivated behaviors are also modulated by environmental stimuli that induce arousal. Time spent mating was found to be a function of the number of potential mates accessible for mating. Number of A. fascinata participating in a mating group was also found to be a function of number of potential mates available.     

Relationship between sexual activity and intraspecific fighting in male mice

Significantly more male mice having cohabited and mated with intact females subsequently displayed intraspecific fighting behavior after castration than males having cohabited with noncycling (ovariectomized) females. Also, intact males that failed to achieve a criterion for aggression during three screening tests subsequently showed a marked increase in fighting after having had copulatory experience relative to males that lived with ovariectomized females. Lastly, spontaneously aggressive males copulated more frequently than nonfighters.     

Perinatal bromopride treatment: effects on sexual behavior of male and female rats

Effects of different perinatal bromopride treatments on sexual behavior were examined in adult male and female rats of Wistar origin. Female rats of mothers treated with bromopride (BRO) during lactation (VB group) and during pregnancy and lactation (BB group) showed lower lordosis quotients than those of controls (VV group). Females of mothers treated with BRO only during pregnancy (BV group) showed no differences in lordosis quotient when compared to the VV group. There were no significant differences in male sexual behavior between experimental and control groups. The effect of bromopride on the control of sexual behavior is discussed.     

The effects of urine on aggressive responses by male golden hamsters

Twenty adult male golden hamsters were isolated into individual cages for a period of six weeks, at the end of which time they had introduced into their home cages, on three occasions, a castrated male intruder. On each occasion the castrated intruder was daubed on the anogenital region with urine from one of three sources: (1) intact females, (2) other castrated males, and (3) intact males. Urine from a different source was applied to the castrated intruder on each of the three tests. Resident males consistently showed more aggression, sniffing, and following and less defensive behavior than the intruders. However, aggression by the resident males showed a significant variance over the three urine treatments given to the intruder. It is concluded that like male mouse urine, male hamster urine contains attack-provoking cues, but that unlike that of the mouse, female urine does not appear to be attack-inhibiting in this species.     

Role of female aggression in prevention of infanticidal behavior in male common voles,Microtus arvalis (Pallas, 1779)

Infanticidal behavior of male common voles (Microtus arvalis) was investigated in relation to the age of unfamiliar pups. Sires from 18 pairs were removed after parturition of their offspring and replaced by unfamiliar males at different ages of the neonates. In group 1, containing six females with their offspring, the new male was introduced into the females' cages on day 1 after the parturition. In group 2 the new male was introduced on day 5 after parturition and in group 3 on day 9 after parturition. The male was removed after 3 days and the neonates recounted. Male common voles killed up to 100% of the neonates in litters containing neonates younger than 9 days by rapid bites to the head of the neonates (groups 1 and 2, mortality rates of 0.86 and 0.38). However, with older pups, a mortality rate of 0.06 was observed while 33% of the intruder males showed signs of injuries (group 3). These findings show that infanticidal behavior of male common voles represents one factor of pup mortality. The results are discussed in relation to changes in the degree of maternal aggression and in the context of the social system of the common vole for solving the conflict between postpartum estrous mating and infanticidal behavior of male common voles. Aggr. Behav. 23:293–298, 1997. © 1997 Wiley-Liss, Inc.     

Gender-specific social experiences and the development of aggressive and sexual behavior in male mice

This study examined influences of gender-specific social experiences on the development of aggressive and sexual behavior in male mice. To determine the effects of gender-specific social experience three different types of groups were constituted after the animals had been weaned. The subjects were randomly assigned to different treatments. Female groups were composed of one experimental male and three female cohabitants. Male groups were composed of five experimental males each, and the mixed-sex groups were composed of two experimental males and of two females. The experimental subjects stayed in these groups until the age of approximately three months, when the testing for sexual and aggressive behavior commenced. For the sexuality tests, a receptive female was placed in the home cage of the experimental male for ten minutes. A nonaggressive male was placed in the home cage of the experimental male for seven minutes for the aggression tests. The experimental males were administered both sexuality and aggression tests, the sequence of testing sexual and aggressive behavior was systematically varied in order to control the influence of the two different types of behavioral tests. The results showed that males with only male social experiences showed fewer responses and were less active in both the aggression and sexuality tests than the males from the two other types of groups. Significant positive correlations between activity during aggression and sexual tests were obtained for all three groups. © 1994 Wiley-Liss, Inc.     

Differential sexual activity of isolated and grouped male mice despite testosterone administration

In Experiment 1, adult male C57 mice were castrated, housed individually or in groups of four, and repeatedly injected with either of two doses of testosterone. Control mice were sham-castrated, individually or group housed, and injected with oil vehicle. In repeated tests of sexual behavior with receptive females, isolated males in all surgery-dose combinations showed significantly more mounts and intromissions than did their group-housed counterparts. Ejaculations were fully restored by testosterone in castrated grouped males but not in castrated isolated males. In Experiment 2, administration of either of two doses of testosterone failed to elevate the sexual behavior of intact group-housed males. These experiments show that housing with other males depresses all major measures of sexual behavior, and suggest that this is probably independent of testicular hormones.     

Maternal stress and pituitary-adrenal manipulations during pregnancy in rats: effects on morphology and sexual behavior of male offspring.

The purpose of the present study was to determine whether the demasculinizing and feminizing effects of prenatal stress (i.e., stress applied to the mother during pregnancy) in rats reported previously are mediated by activation of the maternal pituitary-adrenal axis. Neither whole-body restraint, with or without hyperthermia, nor ACTH treatment during the last third of gestation had any reliable effect on masculine or feminine sexual behavior in male Sprague-Dawley offspring, although these treatments produced maternal pathology and evidence of maternal adrenocorticoid release. Significant littermate similarity was found for almost every morphological and behavioral measure. Failure to control for the litter variable may account for many previously reported effects of prenatal stress on sexual behavior in rats. The discrepancy between the present and earlier findings is discussed in terms of methodological and theoretical considerations.     

Historical,environmental, and behavioral correlates of sexual offending by male adolescents: A critical review

This article is a critical review of research on the historical, environmental, and behavioral correlates of sexual offending by male adolescents. Variables considered include: demographics, victimization history, delinquency history, sexual history, family situation, social/relationships, intellectual functioning, and psychopathology. The review concludes with suggestions for future research and implications for treatment, assessment, and prevention of sexual offending behavior by adolescents.     

Extinction of conditioned sexual responses in male Japanese quail (Coturnix japonica): role of species-typical cues

The authors examined how a conditioned stimulus (CS) that included species-typical cues affected the acquisition and extinction of conditioned sexual responses in male quail (Coturnix japonica). Some subjects were conditioned with a CS that supported sexual responses and included a taxidermic head of a female quail. Others were conditioned with a similar CS that lacked species-typical cues. Pairing the CSs with access to live females increased CS-directed behavior, with the head CS eliciting significantly more responding than the no-head CS. Responding to the head CS persisted during the 42-day, 126-trial extinction phase; responses to the no-head CS extinguished. Responding declined when the cues were removed or the subjects were sexually satiated. Possible functions and mechanisms of these effects are discussed.     

Aggression toward female partners by at-risk young men: the contribution of male adolescent friendships

Deviancy training was examined as a risk factor for physical and psychological aggression toward a female partner among boys and young men in the Oregon Youth Study. Hostile talk about women during videotaped male friendship interactions was hypothesized to indicate a process by which aggression toward women is reinforced within male peer networks. Both antisocial behavior and hostile talk were predicted to be associated with later aggression toward a female partner. Prospective developmental models were tested from 9-10 years of age through young adulthood. Findings indicated that the relation of deviant peer association in adolescence and later aggression toward a partner was mediated by antisocial behavior; observed hostile talk about women with male peers explained additional variance in aggression toward a partner.     

Profiles in coping: responses to sexual harassment across persons, organizations, and cultures

This study explicates the complexity of sexual harassment coping behavior among 4 diverse samples of working women: (a) working-class Hispanic Americans, (b) working-class Anglo Americans, (c) professional Turks, and (d) professional Anglo Americans. K-means cluster analysis revealed 3 common harassment coping profiles: (a) detached, (b) avoidant negotiating, and (c) support seeking. The authors then tested an integrated framework of coping profile determinants, involving social power, stressor severity, social support, and culture. Analysis of variance, chi-square, and discriminant function results identified significant determinants at each of the 4 levels of this ecological model. These findings underscore the importance of focusing on whole patterns of experience--and considering influences at the level of the individual employee and multiple levels of the surrounding context--when studying how women cope with workplace sexual harassment.     

Behavioral effects of stimulation of the medial amygdala in the male rat are modified by prior sexual experience

Researchers have found that stimulation of the medial nucleus of the amygdala (MeA) in male rats increases appetitive copulatory behavior directed toward an anestrous female but suppresses copulation with an estrous female (C. P. Stark et al., 1998). The objective in the present study was to determine if the behavioral change produced by stimulation of the MeA was dependent on chemical and/or visual cues from the conspecific. The author reports that electrical stimulation of the MeA in male rats increased the frequency of mounting and investigative behavior directed toward a male conspecific. However, these effects were limited to those subjects that had no prior sexual experience. Results are discussed in terms of possible experience-dependent alterations in neural response patterns within the MeA and related areas.     

Context effects in visual word recognition: Lexical relatedness and syntactic context

In three experiments, we investigated how associative word-word priming effects in German depend on different types of syntactic context in which the related words are embedded. The associative relation always concerned a verb as prime and a noun as target. Prime word and target word were embedded in visually presented strings of words that formed either a correct sentence, a scrambled list of words, or a sentence in which the target noun and the preceding definite article disagreed in syntactic gender. In contrast to previous studies (O’Seaghdha, 1989; Simpson, Peterson, Casteel, & Burgess, 1989), associative priming effects were not only obtained in correct sentences but also in scrambled word lists. Associative priming, however, was not obtained when the definite article and the target noun disagreed in syntactic gender. The latter finding suggests that a rather local violation of syntactic coherence reduces or eliminates word-word priming effects. The results are discussed in the context of related work on the effect of gender dis-/agreement between a syntactic context and a target noun.     

Conditioning of appetitive and consummatory sexual behavior in male Japanese quail.

Two different types of stimulus objects, a live female quail artificially adorned with bright orange feathers and an inanimate toy dog, served as conditioned stimuli. For subjects in experimental groups, the conditioned stimuli were presented shortly before access to a sexually receptive normal female quail. For subjects in control groups, exposure to the conditioned stimuli was unpaired with copulatory opportunity. Subjects in the experimental but not in the control groups quickly came to approach the location of the conditioned stimulus objects. When an adorned female quail served as the conditioned stimulus, the conditioned approach behavior was controlled by a combination of the presence of the orange adornments and the visual cues of the head and neck of the female bird, and the approach behavior persisted as the adorned female moved to new locations. When the toy dog served as the conditioned stimulus, the conditioned approach behavior was limited to the spatial cues that surrounded the toy dog during conditioning trials. Although both types of stimulus objects evoked conditioned approach behavior, only the adorned female stimulus supported copulatory behavior. This last finding indicates that copulatory behavior can become redirected toward novel stimuli as a result of conditioning, but only under special circumstances. The results are consistent with the suggestion that appetitive components of reproductive behavior are more susceptible to conditioning than consummatory components. Possible reasons for this are discussed, together with implications of the results for the contribution of conditioning processes to sexual selection.