The Influence of Kinship on Familiar Natal Migrant Rhesus Macaques (Macaca mulatta)

In most primate species, females remain in the natal group with kin while males disperse away from kin around the time of puberty. Philopatric females bias their social behavior toward familiar maternal and paternal kin in several species, but little is known about kin bias in the dispersing sex. Male dispersal is likely to be costly because males encounter an increased risk of predation and death, which might be reduced by dispersing together with kin and/or familiar males (individuals that were born and grew up in same natal group) or into a group containing kin and/or familiar males. Here we studied the influence of kinship on familiar natal migrant rhesus macaques (Macaca mulatta) on Cayo Santiago, Puerto Rico, by combining demographic, behavioral, and genetic data. Our data suggest that kinship influences spatial proximity between recent natal immigrants and males familiar to them. Immigrants were significantly nearer to more closely related familiar males than to more distantly related individuals. Within a familiar subgroup, natal migrants were significantly closer to maternal kin, followed by paternal kin, then non-kin, and finally to males related via both the maternal and paternal line. Spatial proximity between natal immigrants and familiar males did not decrease over time in the new group, suggesting that there is no decline in associations between these individuals within the first months of immigration. Overall, our results might indicate that kinship is important for the dispersing sex, at least during natal dispersal when kin are still available.     

Dominant-subordinate relationships in hamsters: sex differences in reactions to familiar opponents

In the majority of mammalian species, males are dominant over and more aggressive than females. In contrast, some reports suggest that female golden hamsters are more aggressive than males but systematic comparisons using the same methods for both sexes are rare. We observed same-sexed pairs of hamsters over repeated trials to assess whether sex differences existed in the level of agonistic behavior and in the development and maintenance of dominant-subordinate relationships with familiar partners. There were no sex differences in measures of agonistic behavior or fear responses (fleeing) during the initial series of three trials on the first day of testing. Following a four-day interval, males that had lost in session 1 showed fearful responses to a familiar dominant male and were not likely to engage in a fight with him. In contrast, females that lost the initial fights were not fearful and fought vigorously with the familiar winner in subsequent encounters. Although the amount of agonistic behavior engaged in by females did decrease over the course of the three sessions, females that lost did not demonstrate an increase in fear, as measured by the latency to flee. Males that lost fights did show increased fear during later trials and sessions. These results suggest that female hamsters are less affected by losing fights than males are and thus that females are less likely than males to develop highly polarized dominant-subordinate relationships. Further work is needed to understand the mechanisms underlying these sex differences.     

Sex-specific responses to sexual familiarity,and the role of olfaction in Drosophila

Studies of mating preferences have largely neglected the potential effects of individuals encountering their previous mates (‘directly sexually familiar’), or new mates that share similarities to previous mates, e.g. from the same family and/or environment (‘phenotypically sexually familiar’). Here, we show that male and female Drosophila melanogaster respond to the direct and phenotypic sexual familiarity of potential mates in fundamentally different ways. We exposed a single focal male or female to two potential partners. In the first experiment, one potential partner was novel (not previously encountered) and one was directly familiar (their previous mate); in the second experiment, one potential partner was novel (unrelated, and from a different environment from the previous mate) and one was phenotypically familiar (from the same family and rearing environment as the previous mate). We found that males preferentially courted novel females over directly or phenotypically familiar females. By contrast, females displayed a weak preference for directly and phenotypically familiar males over novel males. Sex-specific responses to the familiarity of potential mates were significantly weaker or absent in Orco¹ mutants, which lack a co-receptor essential for olfaction, indicating a role for olfactory cues in mate choice over novelty. Collectively, our results show that direct and phenotypic sexual familiarity is detected through olfactory cues and play an important role in sex-specific sexual behaviour.     

Rival recognition in the territorial tawny dragon (Ctenophorus decresii)

The ability to discriminate between familiar and unfamiliar conspecifics is important in territorial animals as it allows animals to distinguish neighbours from non-neighbours. This prevents wasting time and energy in unnecessary aggressive interactions. I investigated the ability of adult males of a territorial lizard, the tawny dragon (Ctenophorus decresii), to distinguish familiar from unfamiliar rivals in a laboratory setting. Males significantly reduced their aggression levels in repeat interactions with familiar rivals and increased their aggression levels towards unfamiliar males. The time taken for interactions to be settled was also significantly lower towards familiar than unfamiliar males. The results of this study suggest that adult male tawny dragons can discriminate familiar from unfamiliar conspecifics. Furthermore, animals were presented with three new rivals in succession and showed a robust ability to discriminate between familiar and unfamiliar males.     

Interactions between Males of the Lizard Liolaemus tenuis: Roles of Familiarity and Memory

For territorial organisms, recognition of familiar individuals can reduce the frequency and intensity of aggressive encounters (‘dear enemy’ phenomenon), stabilize social systems, and reduce the cost of territory maintenance. Here, we investigated the behavioural events displayed during contests between familiar and unfamiliar individuals in the lizard Liolaemus tenuis (Liolaemidae), a species in which males are territorial. The behaviours recorded were attack, warning, evasion, and submission, and the latencies to the first aggressive (attack or warning) behaviour. Additionally, we assessed the ability of individuals to remember a familiar conspecific after a period without social interaction. Individual males reduced and delayed aggressive behaviour directed towards socially familiar individuals compared with unfamiliar ones. These results suggest that males distinguished between familiar and unfamiliar conspecific males and are in agreement with the ‘dear enemy’ phenomenon. Other behaviours were similar in the contests between familiar and unfamiliar individuals. Recognition of familiar conspecifics was lost after 20 d without social interactions. This may be relevant for interactions with floater males or with neighbours that lose their territory and subsequently attempt to fight for their ex‐neighbour's territory.     

Retention of social recognition after hibernation in Belding's ground squirrels

The retention of social memory during long periods of separation, such as hibernation or migration, has not been well documented, despite evidence for long-term social relationships in migrating species or in long-lived sedentary species. We investigated the ability of captive Belding's ground squirrels, Spermophilus beldingi, to remember previously familiar individuals as well as littermates after 9 months of isolation. Before hibernation, young ground squirrels discriminated between odours of familiar and unfamiliar individuals, as shown by greater investigation of a novel individual's odour. The following spring, these yearlings did not respond differentially to odours of previously familiar and unfamiliar individuals, suggesting that memory for familiar conspecifics was lost during hibernation. In contrast, both female and male yearlings continued to discriminate between odours of littermates and previously familiar nonlittermates. Thus, recognition of close kin was maintained during prolonged social isolation, but recognition of familiar, unrelated individuals was not. If re-establishment of familiarity is not costly or if adults rarely interact with the same individuals in successive years, then selection may not favour retention of individual memories of particular conspecifics over the winter. Even though males rarely encounter kin after dispersal, yearling males did recognize their siblings, suggesting that the relative costs of maintaining kin-recognition abilities year-round may be low. Possible mechanisms underlying the formation and maintenance of individual and kin recognition are discussed. Copyright 2000 The Association for the Study of Animal Behaviour.     

The lifetime costs of increased male reproductive effort: courtship,copulation and the Coolidge effect

The reproductive effort that a male directs to a familiar female declines over time, suggesting decreasing marginal returns. But is this diminishing returns a function of increasing reproductive costs or decreasing benefits of sustained effort? Here, we use the restoration of male reproductive effort with unfamiliar females to differentiate the role of diminishing returns and lifetime costs of increased reproductive effort of male guppies. We kept males with familiar or unfamiliar females throughout their lives and manipulated their ability to either court or mate with females. We found that increased male reproductive effort with novel mates lead to an immediate trade‐off in the form of reduced foraging effort. Further, males able to mate with a series of unfamiliar females had lower lifetime growth, indicating the primary cost of male reproductive effort in guppies arises from copulation rather than courtship. The lifetime growth trade‐offs were significant only when males mated with unfamiliar mates, suggesting that male reproductive effort with familiar females declines before it is restricted by physical exhaustion. These findings provide some of the first evidence of longitudinal costs of increased male reproductive effort in a vertebrate.     

根田鼠的熟悉性及其自然动情下的配偶选择

报道了在室内雌鼠自然动情条件下根田鼠两性个体配偶选择的3种熟悉性效应的5组实验结果,包括雌性对熟悉和陌生雄鼠、配偶和陌生雄鼠、配偶和熟悉雄鼠的择偶行为实验 , 雄性对熟悉和陌生雌鼠、配偶和陌生雌鼠的择偶行为实验。在实验前, 将1对性成熟的雌雄鼠 (非亲缘关系) 每天关养8 h 共8 d 建立熟悉性; 配对雌雄鼠至少生育1胎则为配偶关系。在 Y 形迷宫内的30 min 实验中, 两个被选择鼠分别以项链拴在横跨选择箱顶端中央的一根铁丝上, 限制它们在各自箱内活动; 而允许异性选择鼠从中立箱自由进入两个选择箱。记录选择鼠对异性被选择鼠的访问、社会探究、攻击、交配和友好行为的频次和时间。经Wilcoxon 关联样本 T 检验发现, 除交配行为不显著外, 雌性根田鼠均选择熟悉性较高的雄鼠; 而雄鼠不具这种选择性。该结果提示雌雄根田鼠的不同择偶行为也许就是反映该种婚配制度特征的直接行为过程。因此, 在择偶行为中, 雌性根田鼠表现的单配性倾向和雄鼠的多配性倾向, 只能以其婚配制度为一雄多雌制的假设来解释。我们的实验还说明在多配制田鼠中, 一雄多雌制与混交制在雌鼠择偶行为上是不同的, 而与单配制的相似或相近, 故简单地比较多配制与单配制则不能反映田鼠亚科动物婚配制度的多样性。     

Behavioral and Endocrine Responses in Male Marmosets to the Establishment of Multimale Breeding Groups: Evidence for Non-monopolizing Facultative Polyandry

Studies of wild callitrichids provide conflicting evidence regarding polyandrous groups. One perspective supports a monopolizing breeding strategy on the part of one male, while the alternative perspective suggests that polyandry does not lead to a breeding monopoly. We tested the hypotheses in male marmosets (Callithrix kuhlii) with 5 polyandrous groups composed of related/familiar males as our attempts to establish polyandrous groups of unrelated/familiar males failed. We monitored male social and sexual behavior and urinary testosterone (T) and cortisol (CORT) across the first 80 days of group formation and contrasted them with similar measures in males housed in monogamous groups. We also examined the same measures across the females' ovulatory cycles for polyandrous males. We found little evidence that males in polyandrous groups exercised a mating monopoly over the female and no evidence for overt competition between polyandrous males. We found 2 behavioral differences: polyandrous males were less often in proximity and copulated more often with the female than monogamous males did. Our findings suggest that the males in newly-formed groups of marmosets do not monopolize breeding and social behavior with the female. This appears to be the case for 3 reasons. First, males may use sperm competition rather than overt competition. Secondly, it may take longer for relationships to develop between the female and the males in polyandrous groups versus in monogamous groups. Thirdly, the cost of infant care is sufficiently high to demand that group members get along when groups are small and reproductive benefits are shared.     

Olfactory Discrimination of Individual Scents in the Subterranean Rodent Ctenomys talarum (tuco-tuco)

Biological odours that convey cues regarding individual identity can provide valuable information mediating many aspects of mammalian social relationships such us dominance hierarchies, group memberships, territorial and mating activities. The ability of the subterranean rodent, tuco‐tuco (Ctenomys talarum), to discriminate between soiled shavings, urine and faeces from different individuals was investigated using the habituation–discrimination paradigm. Discrimination by both males and females was tested using scents obtained from same‐ and opposite‐sex individuals. Each test subject was habituated for three consecutive days to odour samples from the same individual; on the fourth day a scent from a novel individual was provided. For all odour sources, animals spent significantly less time investigating the habituation scent over successive trials, indicating that animals perceived the stimulus as familiar. For all stimuli, test subjects spent more time investigating the novel odour, rather than the familiar one. Animals spent more time investigating soiled shavings than urine or faeces. Both males and females discriminated novel from familiar odours in shavings and urine regardless of the gender of the odour donors. In contrast, test animals discriminated between familiar and novel odours in feces only when the fecal donors were of different sex from subjects. Possible territorial and reproductive functions of individual scent discrimination are discussed.     

The effect of familiarity on social interactions in meadow voles,Microtus pennsylvanicus: a laboratory and field study

The role of familiarity in affecting the outcome of social interactions among meadow voles was investigated in both a laboratory and a field experiment. In the laboratory, captive meadow voles, Microtus pennsylvanicus, were exposed to a conspecific's odour. The voles were then placed into two groups: familiar and unfamiliar. Familiar voles were individuals who underwent staged dyadic encounters with the conspecific to whose odours they had been exposed. Unfamiliar voles were individuals who underwent paired encounters with conspecifics to whose odours they had not been exposed. In the field experiment, familiar voles were neighbours that were trapped within each other's home ranges over two consecutive bi-weekly trapping sessions. Unfamiliar voles were individuals that were trapped on different trapping grids. The results of the laboratory and field studies were similar. Encounters between familiar females resulted in less agonistic behaviour and more amicable acts than encounters between unfamiliar females. In contrast, encounters between familiar males resulted in more agonistic behaviour than encounters between unfamiliar males. Familiarity did not affect the outcome of male-female interactions. These results are discussed in the framework of the social system of the meadow vole.     

The effects of familiarity and group size on mating preferences in the guppy,Poecilia reticulata

Abstract In recent years, it has become evident that frequency dependence in the attractiveness of a particular phenotype to mates can contribute to the maintenance of polymorphism. However, these preferences for rare and unfamiliar male phenotypes have only been demonstrated in small, controlled experiments. Here, we tested the preference for unfamiliar mates in groups of six to 96 individuals over 13 days, in the guppy (Poecilia reticulata). We observed individual behaviour in situ to test whether fish discriminate two unfamiliar individuals among many familiar ones. We found that unfamiliar males and females were preferred over the familiar fishes in all groups and that this effect decayed over time. Increasing group sizes and levels of sexual activity did not hamper the preference for unfamiliar mates, providing further support for the role of frequency dependent mate choice in the maintenance of trait polymorphism in natural populations.     

Integration of New Males into Four Social Groups of Tufted Capuchins (Cebus apella)

We examined how aggressive, affiliative, and sexual behavior function to integrate male capuchins (Cebus apella) into a new social group. Nine males were exchanged among four social groups. We performed instantaneous scans and all-occurrence sampling during baseline, introduction, and follow-up periods. The study included three different introduction situations: 1) males familiar to one another were introduced to a group with no other adult male, 2) males unfamiliar to one another were introduced to a group with no other adult male, and 3) males familiar to one another were introduced to a group with an existing elderly, resident male. Severe aggression occurred in situations 2 and 3, but the introductions were peaceful in situation 1. In all cases proceptive females were among the first individuals to affiliate with the males, and males did not appear to compete for access to proceptive females. Following their period of proceptivity, the females that had cycled remained preferred social partners for the males. Immature animals also quickly affiliated with the new males, and the males tolerated the attention from immatures. Affiliative relationships between the males and nonproceptive females developed slowly, and while male-female aggression was mild, aggression among adult males (familiar and unfamiliar) had the potential to be severe.     

Patterns of neural activation associated with exposure to odors from a familiar winner in male golden hamsters

The neural mechanisms underlying recognition of familiar individuals and responses appropriate to them are not well known. Previous studies with male golden hamsters have shown that, after a series of brief aggressive encounters, a loser selectively avoids his own, familiar winner but does not avoid other males. Using this paradigm, we investigated activity in 20 areas of the brain using immunohistochemistry for c-Fos and Egr-1 during exposure to a familiar winner compared to control groups not exposed to another male. Behavioral data showed that 1 day after fights males that lost avoided the familiar winner, suggesting that they recognized this individual. The c-Fos and Egr-1 immunohistochemistry showed that the losers exposed to familiar winners had a greater density of stained cells in the basolateral amygdala, the CA1 region of anterior dorsal hippocampus and the dorsal subiculum than control groups had in these areas. These results suggest that these brain areas may be involved in the memory for other males, the learned fear of familiar winners, or related processes.     

Room novelty, sex, scopolamine and their interactions as determinants of general activity and rearing, and light-dark preferences in rats

Male and female rats were assessed for effects of scopolamine on general activity, rearing and light-dark preferences when tested in either a familiar or a novel room. Males but not females reared more often when tested in the familiar rather than novel room, and the response was increased by scopolamine for all rats combined. Whereas scopolamine increased general activity for females (but not males) in the familiar room, it decreased the response for males (but not females) in the novel room. Females crossed more often between the dark and light sides of a light-dark box and, when treated with saline but not drug, spent more time in the light side than males. Scopolamine reduced the amount of time spent in the light side for females only. While the results were discussed mainly in terms of sex differences in fearfulness, their principal value was in demonstrating the effectiveness of room novelty and sex in determining levels of the behaviors recorded, and drug responsiveness.     

Mating Preferences of the Gynogenetic Amazon Molly Differ Between Populations Sympatric with Different Host Species

Gynogenetic species rely on sperm from heterospecifics for reproduction but do not receive genetic benefits from mating because none of the paternal genome is incorporated into offspring. The gynogenetic Amazon molly (Poecilia formosa) is a species of hybrid origins that are sympatric with one of the two parent species that provide sperm for reproduction, P. latipinna or P. mexicana. Amazons should not prefer to mate with one species over the other because sperm from both species will trigger embryogenesis, but mating preferences may be present in Amazons through other mechanisms. Amazons may prefer the more familiar species (males found in sympatry), or Amazons may prefer males with the greatest lateral projection area (LPA), a preference that is present in the parent species and may be retained within the Amazon hybrid genome. We tested association preferences of two populations of Amazons sympatric with either P. mexicana or P. latipinna. We first performed live trials to test whether Amazons preferred one host species over the other and found that neither population of Amazons showed a preference. We then tested whether Amazons preferred sympatric male (familiar) host or the male with the greatest lateral projection area (LPA) using four animated male models that varied in host species and manipulation of LPA. We found Amazons from a population sympatric with P. latipinna showed no variation in their association preference across the different models. In contrast, Amazons from a population sympatric with P. mexicana (naturally small LPA) spent more time associating with the male models that had smaller LPA, which is more familiar to this population of Amazons. We suggest that Amazons may have population differences in mating preferences, where Amazons sympatric with P. latipinna may not show mating preference for host species, but Amazons sympatric with P. mexicana may show preferences for more familiar‐shaped males.     

Size-Dependent Chemosensory Responses to Familiar and Unfamiliar Conspecific Faecal Pellets by the Iberian Rock-Lizard, Lacerta monticola

We conducted a field study to analyse the social relationships between males of the Iberian rock lizard (Lacerta monticola). The degree of familiarity was determined based on the degree of overlap between their home ranges. We then designed a laboratory experiment to test whether the same males were able to discriminate between familiar and unfamiliar conspecifics using faecal pellet odours. Differential tongue‐flick rates suggest that large males (snout‐to‐vent length, SVL > 75 mm), at least, may discriminate between odours of familiar and unfamiliar males. The behavioural responses were dependent on relative differences in body size between the responding male and the male that donated the faecal pellet. Thus, as responding small males increased in size relative to their corresponding familiar male, their rate of tongue‐flicking significantly decreased; this was not the case in response to unfamiliar males. In contrast, there were no significant correlations between the response of large males to familiar or unfamiliar male stimuli, regardless of size differences. These results suggest that chemical cues contained in faecal pellets allow individual recognition in male L. monticola, and that the response depends on body size. We suggest that faecal pellets might be used to scent‐mark home ranges, which would contribute to lowering the costs of aggressive interactions.     

Sexual arousal,the coolidge effect and dominance in the rat (rattus norvegicus)

Male rats were ranked in dominance orders, were allowed to copulate to exhaustion and then were tested for sexual rearousal in five different treatment conditions. Novel females rearoused 60 per cent of the males to ejaculation. Five-minute encounters with dominant or subordinate males stimulated 33 per cent to ejaculation with a familiar female. Fifteen per cent ejaculated with the familiar female after a 5 min rest and 15 per cent after an encounter with an unknown male. The degree of rearousal was not related to fighting or to mounting during male-male encounters, nor did the dominant males show a higher degree of sexual potency.     

Olfactory communication and the importance of different odour sources in the ferret (Mustela putorius f. furo)

Olfactory communication has a major role in solitary carnivores, particularly during the breeding season. Scent-marking behaviour in ferret (Mustela putorius f. furo) has been well studied, but not the significance of the deposited odours for the animal. We compared the interest in urogenital, anal and body odours of opposite-sex conspecifics between male and female ferrets and investigated both sexes’ discrimination ability (familiar vs. unfamiliar) for these three opposite-sex odours and the use of its ability by females during the breeding season. Males are more interested than females in the urogenital odour of the opposite sex. Male body odour probably did not interest females and males are somewhat interested in the female one. However, anal odour of the opposite sex is as interesting for males as for females and both sexes are able to discriminate familiar anal odour from an unfamiliar one. Moreover, females could use this ability when they must choose to have some sensory contact between olfactory familiar and unfamiliar males since they prefer to be in contact with the former. These results are coherent with behavioural differences observed between male and female solitary mustelids in the field and in captivity, and the consortship success of resident males compared to roaming males.     

黄毛鼠婚配制度初探:熟悉性对两性间行为的影响

为探究黄毛鼠的婚配制度,通过雌雄黄毛鼠对熟悉和陌生异性鼠的选择实验和遭遇实验,分析了熟悉性对两性间行为的影响.结果发现,选择实验中雌鼠对陌生雄鼠的关注频次比对熟悉雄鼠的更多;遭遇实验中尽管雌鼠探究和自身修饰行为、雄鼠的活动和攻击行为在遭遇熟悉或陌生异性鼠时有差异,但雌雄鼠的友好行为均无显著差异,暗示黄毛鼠是多配制,但需...