Unfamiliar Females Research Articles

Attachment and preschool children's understanding of maternal versus non‐maternal psychological states

There is growing evidence that insecurely attached children are less advanced in their social understanding than their secure counterparts. However, attachment may also predict how individual children use their social understanding across different relationships. For instance, the insecure child's social‐cognitive difficulties may be more pronounced when the psychological states of an attachment figure are being considered. In the current study, forty‐eight 4‐ to 5‐year‐old children were asked about their mothers' emotions and false beliefs, as well as those of non‐attachment figures. The Separation Anxiety Test (SAT) was administered to assess children's attachment representations. Children's SAT scores predicted their overall performance on the false belief and causes of emotion tasks, even after controlling for age and verbal ability. More interestingly, however, children with high scores on the Avoidance dimension of the SAT experienced greater difficulty understanding maternal false beliefs relative to those of an unfamiliar adult female. Thus, although attachment insecurity may hinder social‐cognitive development in general, the findings suggest that there are more specific effects as well. Attachment representations that are characterized by high levels of avoidance appear to interfere with children's ability to fully engage their social‐cognitive skills when reasoning about maternal mental states.

Fatal Attack on an Adult Female Cercopithecus mitis erythrarchus: Implications for Female Dispersal in Female-Bonded Societies

Female dispersal is uncommon among female-bonded primate societies, even though at times there may be considerable incentive to do so, e.g., to avoid potentially infanticidal males. Predation risk and the advantages of sharing the costs of group living, such as infanticide and resource defense, with close kin are assumed to limit female dispersal. However, we show that these costs may not be as important as the risks associated with integration into a new group in female-bonded societies. We report the death of a potentially dispersing solitary Samango (Cercopithecus mitis erythrarchus). She was unrelated to the females of a single group that killed her, and her death was not in the context of intergroup conflict or territorial defense. This fatal conflict is in contrast to the tolerance of female dispersal displayed by many folivorous and non-female-bonded primate species. In such non-female-bonded societies, there is less indirect fitness advantage to remaining in the natal group or to cooperate with kin to defend food patches, and consequently the risk of being rejected by another group is much reduced. Our observations show that dispersal between groups may be costly for solitary and unfamiliar females in a female-bonded society.

Factors Affecting the Successful Pairing of Unfamiliar Common Marmoset (Callithrix Jacchus) Females: Preliminary Results

AbstractLaboratory primates are often housed in same-sex pairs to avoid single-housing and when breeding is to be prevented. However, pair formation is not without risks, as fights and injuries may occur. No data are available on pair formation in female common marmosets(Callithrix jacchus), a species used extensively in laboratories. Therefore, this study focuses on the pairing of unfamiliar common marmoset females, aiming to assess its success rate and whether age can predict the result. Data on the study animals and success of the pairings were extracted from laboratory back-records: a total of 28 pairings was obtained. In addition, behavioural data were collected on six of the 28 pairs. Almost 80% of pairs were compatible beyond one week, and most of the fights occurred well within the first week after pair formation. Pairs in which one of the females was sexually immature (ie < 15 months) were significantly more compatible than pairs in which both females were post-pubertal. First encounters were characterised by sniffing of the unfamiliar monkey. Aggressive behaviours occurred frequently following pair formation but they were unidirectional, and in only two pairs was veterinary treatment required. This study shows that pairing of unfamiliar common marmoset females is a safe practice if one monkey is sexually immature, a result that supports observations of both group and pair formation in other primate species. However, given the potentially detrimental effects of removing young females from their natal groups, we argue that it is preferable to remove two sisters from their natal group when female pairs are required. However, when a single sexually mature female requires a pair mate so as to avoid single-housing and no mature sibling is available, an older, but still sexually immature, unfamiliar female that has had a normal development within the family should be considered as a pair mate.

For whom the male calls: an effect of audience on contact call rate and repertoire in budgerigars, Melopsittacus undulatus

Budgerigars are well known for their ability to imitate sounds, but little is known about the functional contexts in which they use these imitations. Recently, we have shown that male budgerigars consistently imitate the contact calls of the females with whom they are paired. Here we investigate whether males produce these imitations more frequently when they are with their mates than when they are with other females. In one experiment, we established seven budgerigar pairs and then tested each male with his mate and with an unfamiliar female. In the second experiment, we allowed pairs to form freely in an aviary and then tested the males with their mate and with a familiar mated female. In both experiments, the males produced significantly more imitations of their mate's call (defined as calls that were more than 75% similar to the mate's predominant contact call) when they were with their mate than when they were recorded with another female. Under aviary conditions, this difference was due to both a general increase in the males' rate of calling and to an increase in the percentage of the males' calls that were imitations. These data show that male budgerigars modify their contact call rates and repertoires in an audience-specific manner. This audience effect is unusual because it involves a learned vocalization and is extremely specific to a particular audience, namely the mate. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.

The perirhinal–entorhinal cortex, but not the hippocampus, is critical for expression of individual recognition in the context of the Coolidge effect

The Coolidge effect is a phenomenon in which males show renewed sexual interest in a novel female following copulation to satiety with another female. In golden hamsters, this phenomenon depends on the ability to recognize conspecifics using chemosensory cues processed through the main olfactory system. Here we tested whether olfactory targets in the hippocampal system support this natural form of recognition memory. Male hamsters received ibotenic acid lesions of the perirhinal–entorhinal cortex (PR-ENT) or hippocampus (H) and were allowed to copulate to satiety with a female conspecific, then were presented with two anesthetized females, the familiar mate and an unfamiliar female that copulated with another male. Sham-operated and H-lesioned subjects preferentially investigated the novel female, indicating intact recognition of individual identity. By contrast, PR-ENT-lesioned males failed to discriminate familiar and novel females, and this deficit could not be attributed to abnormal copulatory behavior during mating. All subjects were able to detect and discriminate between female odors when presented in isolation during a habituation-discrimination test, indicating that behavioral deficits shown by PR-ENT males were not due to anosmia or a general investigatory deficit. Thus, the perirhinal–entorhinal cortex, but not the hippocampus, is critical for the recognition of familiar conspecifics in this naturalistic situation. This study reveals an essential role for the perirhinal–entorhinal cortex, but not the hippocampus, in a natural form of recognition memory within the social behavior of hamsters. The findings show a strikingly similar pattern to the effects of selective damage to the same brain regions on performance in standard recognition memory tasks by rats and monkeys. Therefore, the present data extend our understanding of the differential role of structures of the hippocampal memory system, showing continuity across species and between formal laboratory tests and the function of memory in natural social behavior.

Determinants of social rank in female black-capped chickadees (Poecile atricapilla)

Black-capped chickadees (Poecile atricapilla) mate assortatively by social rank. Previous field studies suggest that intrinsic characteristics of females may influence success at pairing with dominant males. Here we examined factors leading to dominance using dyads of captive unfamiliar females. The owner–intruder hypothesis predicts that prior residency determines dominant–subordinate relationships. The resource-value hypothesis suggests that social status is initially determined by need and the relationship persists through familiarity of the interactants. The resource holding potential hypothesis suggests that individuals win in dyadic contests because of intrinsic characteristics such as size or age. We tested the owner–intruder and resource-value hypotheses by allowing females prior residency in aviaries where dominance interactions subsequently occurred and by food depriving the intruders. Post-hoc comparisons of dominant–subordinate attributes tested the resource holding potential hypothesis. We found that owners were more likely to win interactions. Hungry individuals showed no competitive advantage. Dominants and subordinates did not differ in morphology or age. Our results agree with data from willow tits (Parus montanus) which show that captive females establish dominance independent of males and that prior residence plays a key role. These findings, together with field studies, suggest that assortative mating in chickadees results, at least in part, from intrasexual interactions among females.

Sexual interactions of maturing male guinea pigs with their mothers, sisters, and unfamiliar adult females in the home cage.

During observations in the home cage in the light and dark on days 5, 15, 25, 35, and 45, male guinea pigs mounted and exhibited anogenital investigation of the mother, though appropriately directed mounting occurred infrequently and was not shown by all males. Mothers nipped and kicked advancing males. No mounting of a female sibling was observed. When behavioral interactions of approximately 35-day-old males with the mother or an unfamiliar adult female were compared during 1-hr tests in the home cage, males exhibited much higher levels of mounting and anogenital investigation, and received many more nips and kicks, when with the unfamiliar female. The results 1) demonstrate that limited maternally directed sexual behavior occurs in the home cage, 2) support earlier findings indicating that continuous housing with the mother suppresses maternally directed sexual behavior in periadolescent guinea pig males, and 3) suggest that sexual behavior toward female siblings also is suppressed.

Reproductive Signals of Female Lizards: Pattern of Trait Expression and Male Response

AbstractRelative to the volume of studies concerning the function and evolution of male‐biased sexually dimorphic traits, instances of female‐biased sexual dimorphisms remain largely unstudied, especially in species with conventional sex roles. I investigated the signal function of a female‐specific ornamental trait using the striped plateau lizard (Sceloporus virgatus, Phrynosomatidae) as a model system. During the reproductive season, female S. virgatus develop orange color on their throats that is absent in conspecific males. I established the relationship between color expression and female reproductive state, and determined male response to female color. I show that dynamic changes occurring within the color patch can potentially identify each stage of the female reproductive cycle, largely because of a lag in patch growth relative to color intensification. Sexual receptivity is associated with intense patches rapidly growing in size; ovulation occurs near peak color expression; and the unreceptive period is associated with large patches fading in intensity. Because females express orange color during both the receptive and unreceptive periods, the pattern of color expression is consistent with the courtship‐stimulation and courtship‐rejection hypotheses of signal function. Males may preferentially associate with females that have more highly developed color patches during the courtship season, and/or ignore such females when they are unreceptive. An examination of male behavior towards unfamiliar females indicates that female color has a role in courtship stimulation but has little, if any, role in courtship rejection. During the pre‐mating season, males maintained significantly closer affiliation with, and tended to perform more social behavior towards females with more intense color. During the post‐mating season, female color had no apparent effect on male behavior. The evolution and current function of female ornaments may vary among taxonomically‐related species as a result of differences in ecology, social system, and life‐history.

Presence of Mother and Unfamiliar Female Alters Levels of Testosterone, Progesterone, Cortisol, Adrenocorticotropin, and Behavior in Maturing Guinea Pigs

Although the guinea pig is characterized by precocial physical development and minimal active maternal care, studies suggest the presence of the mother can influence neuroendocrine and behavioral activity of offspring even well beyond weaning. Previous results may have been influenced by the procedure of housing weaned subjects with the mother to within 2 days of testing. The present study examined ∼40-day-old guinea pigs housed apart from the mother for 0 (not rehoused), 2, or 10 days. Rehousing without the mother led to elevations in plasma testosterone (measured in males), progesterone (measured in females), cortisol, and adrenocorticotropin (ACTH) (both measured in males and females). Offspring housed without the mother for 10 days had the highest progesterone, cortisol, and ACTH levels. Testosterone elevations were observed in 2-day-, but not 10-day-, rehoused animals. Regardless of rehousing condition, 60 min isolation in a novel test cage elevated progesterone, cortisol, and ACTH, and reduced testosterone. These effects were all moderated if the subject was tested with the mother or another female. Sexual behavior toward the mother was observed frequently, but only in males housed apart from her prior to testing. Overall, males and females that had been housed apart from the mother interacted with her as they would an unfamiliar female. Our results corroborate previous findings, suggest the effect of housing apart from the mother on male testosterone is transitory, and indicate that continuous housing with the mother past weaning suppresses circulating progesterone in females and cortisol and ACTH in both sexes.

Social influences on cortisol and behavioral responses of preweaning, periadolescent, and adult guinea pigs

In various species, the presence of an attachment figure can reduce hypothalamic–pituitary–adrenal (HPA) responses. In the guinea pig, the mother reduces HPA elevations of her young both prior to and following weaning. Recently, an unfamiliar female was also found to reduce the HPA responses of postweaning guinea pigs. The present study evaluated the specificity and ontogenetic course of the effect of the unfamiliar female. Experiment 1 found that an unfamiliar adult male did not reduce the cortisol response of periadolescent subjects during novelty exposure. Experiment 2 showed that the effect of the unfamiliar female was present as early as the second week of life. Experiment 3 found that neither an unfamiliar adult female nor male affected the cortisol response in adult guinea pigs. In all experiments, the mother reduced the cortisol elevations of her offspring. The ability to buffer the cortisol response could not be explained by the amount of agonistic behavior subjects received from the stimulus animals. Results indicate that the mother guinea pig has a persisting ability to buffer HPA responses in her developing offspring; that during at least a large portion of the time that the mother can moderate the cortisol response of her young, so too can an unfamiliar adult female, but not an unfamiliar adult male; and that the ability of social partners to moderate HPA activity is not readily predictable from behavioral interactions.

Is use of a novel food source by young canaries (Serinus canarius) influenced by the sex and familiarity of the adult demonstrator?

AbstractThe influence of experienced males or females on the use of a novel food (canary seed) by juvenile canaries was studied. The tutors were either the parents, which reared the juvenile or unknown adults. In the Experiment 1, the various tutors and the juvenile could see each other through a transparent wall. We tested (i) in the young: the use of seed, the attraction towards adults and the reduction of fear, if any, brought about by the presence of the tutor, (ii) in the adults: feeding activity. Manipulation of seeds by juveniles was greater in the presence of their father than in the presence of unknown males and a stronger effect of local enhancement was observed. In the presence of familiar or unfamiliar females, manipulation of seeds was always strongly enhanced. Juveniles ingested more seeds in the presence of familiar birds of either sex than in the presence of unfamiliar birds. The study of attraction towards the adults revealed that the young could distinguish familiar from unfamiliar adults. Fear was reduced more strongly in the presence of females and familiar birds. Adult females showed high feeding activity, which was not influenced by the presence of a juvenile whether familiar or not. Among males, the consumption of seed was only high in the presence of a familiar juvenile. Detailed analysis showed that the use of seed by the juveniles was favoured by the reduction of fear brought about by the presence of the father and of females. The feeding activity of adult females significantly facilitated the use of novel food by the young. No significant effect of the presence or the activity of an unfamiliar adult male was found. Experiment 2 showed that a familiar male adult and a juvenile exerted a reciprocal influence on each other. Observation of the father was required for facilitation of seed use by juveniles. The father consumed seed whether it could see the juvenile or not but, seeing the juvenile increased seed intake significantly. In the canary, the male looks after the young, which he feeds after fledging. His behaviour favours the use of new food by the young and hence the survival of his offspring.

EFFECT OF ODOUR CUES ON THE EXPLORATORY BEHAVIOUR OF FEMALE COMMON VOLES LIVING IN MATRIARCHAL GROUPS

AbstractSeven matriarchal breeding groups of common voles (Microtus arvalis) were studied to test bonding between females when given the option to leave their family group, and the hypothesis that they explore more in areas with odours from related individuals compared to areas scented with odours from unrelated individuals.Young females were observed more frequently in the proximity of their mother and were recorded more often with their sisters than alone. Except for reproductive females, all females were seen more frequently in the initial home area than in areas of exploration. Females frequented an area scented with the odour of related females more often than one with the odour of unrelated, unfamiliar females, but only shortly before dark. In most test groups only the adult females reproduced although their daughters had reached the age of sexual maturity. The results indicate that young female M. arvalis tend to stay with their mother and may delay their own reproduction. When exploring the vicinity of the burrow young females tend to prefer areas with the scent from related females and can recognize odour cues after being separated from the odour donor for 3.5 weeks. This behaviour may minimize aggressive encounters, leading to dispersal toward related individuals.

Responses to olfactory stimuli in spotted hyenas (Crocuta crocuta): II. Discrimination of conspecific scent.

Scent marking in spotted hyenas (Crocuta crocuta) includes the deposition of anal sac secretions, or "paste," and presumably advertises territorial ownership. To test whether captive hyenas classify and discriminate individuals using odor cues in paste, the authors conducted behavioral discrimination bioassays and recorded hyena investigation of paste extracted from various conspecific donors. In Experiment 1, subjects directed most investigative behavior toward scents from unfamiliar hyenas and members of the opposite sex. In Experiment 2, male hyenas discriminated between concurrent presentations of paste from various unfamiliar females in similar reproductive states. Thus, pasted scent marks convey information about the sex, familiarity, and even identity of conspecifics. Aside from territory maintenance, scent marking may also communicate information about individual sexual status.

Effects of female presence on intrasexual aggression in male lizards, Podarcis hispanicus

AbstractResource value and expected gain in reproduction may affect motivation to fight and the likelihood of winning. Previous experiments have showed that males increase their fighting effort when defending a territory that contains females. However, we hypothesized that for an intruding lizard, the value of a new territory may be lower if he already has a female in his own territory, and consequently, aggressivity should be lesser than if he has no access to any female. We staged encounters between males of the lizard Podarcis hispanicus in outdoor terraria to analyze the outcome and detailed behaviors involved in agonistic interactions in the presence or absence of a female in the terraria of resident and intruders. Our results showed that when a female was present, the level of aggressivity of the resident male was higher; the probability of winning the contest also increased, but only if the intruding male had no females in his own terraria. In contrast, when the intruding male was also the owner of another territory containing a female, residents were less aggressive. We suggest that the lack of information on the reproductive state of an unfamiliar female may be enough to decrease fighting motivation of an intruding male, if he has more expectations of success with his own familiar female. We conclude that differences in expected reproductive success with different females may help to decide the outcome of conflicts between males quicker and cheaper. Aggr. Behav. 28:491–498, 2002. © 2002 Wiley‐Liss, Inc.

Nest, but Not Egg, Fidelity in a Territorial Salamander

Egg recognition and subsequent egg brooding are costly forms of parental investment in many species of vertebrates. Life history factors, such as coloniality or risk of brood parasitism, may constrain egg recognition in vertebrates. Female red‐backed salamanders (Plethodon cinereus) from my study site are territorial and do not share nest sites with other females. They are terrestrial and neither they nor their eggs are likely to be displaced by environmental factors such as flooding. I experimentally tested, in the laboratory, the hypothesis that female red‐backed salamanders can discriminate between their own eggs and the eggs of unfamiliar females. Each female was allowed to move about a test chamber containing two clutches of eggs, one clutch with which it was found in the forest and one that had been found with a distant female. Most females remained with one clutch of eggs, which they brooded during the entire observation period. However, they did not significantly prefer to brood their own eggs over the eggs of another female. In a corollary field experiment, I tested whether brooding females that were displaced 1 m from their nest sites would return to their territories and commence brooding behaviour within 3 d. All 10 displaced females returned to their own nest within this time period and were found brooding their eggs. Because female red‐backed salamanders at my study site do not tend to share nest sites with other females and because their eggs remain in stationary nests, selection may not have favoured egg recognition. However, the results suggest that female salamanders indirectly recognize their own eggs by actively recognizing their territorial nest sites.

Consequences of the presence of the mother or unfamiliar adult female on cortisol, ACTH, testosterone and behavioral responses of periadolescent guinea pigs during exposure to novelty.

Periadolescent guinea pigs were exposed to a novel environment for 10, 30, 60, or 90 min while either alone or with either their biological mother or an unfamiliar adult female. Both classes of females reduced plasma cortisol, ACTH and vocalization responses to the novel environment, and did so to an equivalent degree. However, behavioral interactions with the mother and unfamiliar female differed considerably. The offspring exhibited more defensive behavior and were the targets of more agonistic acts when with the unfamiliar female, though one agonistic behavior, kicking, was observed more often in tests with the mother. Males displayed more social/courtship behavior and tumescence with the unfamiliar female. Further, males exhibited higher plasma testosterone levels when with the unfamiliar female than when either with the mother or alone. These data in conjunction with earlier findings suggest that the ability of unfamiliar adult females to moderate hypothalamic-pituitary-adrenal activity fully emerges during the periadolescent period, is not dependent on nurturant behavior by the adult female, and may facilitate the redirection of social behavior from the mother to unrelated adults. Further, mothers appear to inhibit maternally directed sexual behavior and plasma testosterone elevations in their periadolescent sons, effects which likely serve to inhibit inbreeding.

Social environment and immunity in male red jungle fowl

We examined the relationship between social dominance, immune response, and ornamentation in captive red jungle fowl by comparing these variables in males housed individually with a single female to those in the same males after they were placed in flocks with an unfamiliar male and three unfamiliar females. Males with larger combs before being placed in the flocks were more likely to become dominant, and dominant males’ combs grew after flock formation, whereas subordinate males’ combs shrank. Immune response as reflected in hematocrit, immunoglobulin levels, and wing web swelling (a measure of cell-mediated immunity) was stronger in males that later became dominant, both before and after flock formation, although the difference between dominant and subordinate birds was more pronounced after males were housed in the multi-male groups. Dominant and subordinate males also differed in the relationship between comb length and wing web swelling. Among dominant males, individuals with larger combs had significantly larger swellings after flock formation, whereas within the subordinate males, those with relatively larger combs had worse cell-mediated immunity than those with smaller combs. These results suggest that males of different quality pay different costs to maintain both ornamentation and immune defense.

Lipopolysaccharide facilitates partner preference behaviors in female prairie voles

Exposure to proinflammatory cytokines (e.g., IL-1β) or lipopolysaccharide (LPS) produces an acute activation of the immune response and results in a repertoire of behavioral patterns collectively termed sickness behaviors. Although nonspecific responses to pathogenic infection have traditionally been viewed as maladaptive effects of infection, sickness behaviors may have significant, adaptive value for the host. One set of adaptive behaviors affected by infection among mammals and birds is mate choice. In Experiment 1, female prairie voles exhibited the expected increase in blood corticosterone concentrations in response to a 0.1 cc i.p. LPS injection (50 μg), indicating activation of the endocrine system. A separate cohort of females was injected with LPS or saline and paired for 6 h with a novel, previously unpaired male. Following the cohabitation period, LPS-injected females spent significantly more time ( p < 0.05) with the familiar partner when given a choice between familiar and unfamiliar males in a three-chamber apparatus designed to test partner preferences. Saline-injected females spent significantly more time with the unfamiliar male. In Experiment 2, males injected with LPS or saline spent equal amounts of time with familiar and unfamiliar females following a 6 h cohabitation with a naive female, and therefore, did not exhibit preferences. From a proximate perspective, this study provides evidence that sickness behaviors influence female, but not male, partner preference in prairie voles.

Familiarity breeds contempt in guppies.

Male guppy fish increase their reproductive success by mating with unfamiliar females. When President Coolidge famously attributed the sexual ardour of roosters on a government farm to a steady stream of new hens1, he identified a strategy whereby males increase their reproductive success. By preferentially copulating with different females, a polygamous male will facilitate the spread of his genes and sire more offspring2. But in order to benefit, a male must either have the cognitive skills to recognize familiar females, or behaviour patterns that increase his likelihood of encountering new ones. We show here that wild guppies, Poecilia reticulata, do both.

Contextual determinants of female–female mounting in laboratory rats

Female–female mounting is widespread among mammalian species, but little is known about the proximal function of this behaviour. While such mounting is often regarded as a ‘masculine’ trait, its widespread occurrence may indicate that it serves specific functions within the context of female–female social behaviour. We valuated female mounting behaviour in Long–Evans rats in standard observation chambers and in a seminatural enclosure. Under these conditions, we examined a number of potential factors that might influence mounting, including the oestrous cycle, social hierarchy, familiarity and male presence. The female’s mounting was not influenced by her own oestrous cycle, but did vary with the oestrous cycle of the stimulus female. Socially dominant females mounted significantly more than subordinate females, and mounting by the dominant female was most frequent when the subordinate female was sexually receptive. Females mounted (and fought with) unfamiliar females significantly more than they did with familiar cagemates. Female–female mounting was dramatically reduced when males were present. Further testing showed that female mounting did not affect the induction of the progestational state of pregnancy, suggesting that female mounting does not function as a pseudomale behaviour that can substitute for genital stimulation provided by the male. Based on these data, female mounting does not appear to function as a sexual behaviour per se, but may serve as a form of female social behaviour related to maintenance of the female’s social status within female groups. In this regard, the results of this study suggest that female mounting is part of the normal female’s complex behavioural repertoire and does not necessarily reflect masculinization of some underlying neural substrate.