The Ontogeny of Social Behaviour in Four Conilurine Rodents (Muridae) of Australia

This paper describes the ontogeny of social behaviour in 4 closely related rodents from diverse habitats. These rodents, Notomys alexis, Pseudomys albocinereus, P. shortridgei and P. desertor exemplify 4 different social organizations. The young were observed daily under semi-natural conditions until weaning, and subsequently at intervals of one week until sexual maturity. Relationships between the young and their families were determined from the relative frequencies of attracting (amicable) and repelling (agonistic) behaviour. The social behaviour of the young is correlated with the social behaviour of adults. Social interactions experienced from birth throughout sub-adulthood appear to prepare these species for their adult social life.     

Male and female agonistic and affiliative relationships in a social group of farm cats (Felis catus L.)

A dominance hierarchy based on the outcome of agonistic encounters was found among male and female domestic cats. A female dominated over some males. The dominance concept is also discussed in terms of social bonding. The relationships among adult females were amicable, whereas adult males showed reciprocal tolerance. The flow of affiliative behaviour was directed mainly from females to one male of the group. The analysis of marking behaviour showed that this male sprayed urine and rubbed the perioral and cheek regions of the face on the objects of the environment at a higher rate than the other members of the group. Nevertheless, rubbing the perioral and cheek regions of the face on objects was not correlated to dominance rank, possibly because it has some function in social communication other than territorial defence against strangers. No relationships have been found between claw scratching, rolling on the ground and social rank, or between the former and other marking behaviour. It is concluded that claw scratching and rolling were not utilised to mark territory.     

White-faced capuchin monkeys show triadic awareness in their choice of allies

The social intelligence hypothesis, which holds that social challenges have selected for increased intelligence and social skills, has been supported by evidence that, in catarrhine primates, individuals know about the characteristics of groupmates' social relationships. Evidence for such ‘triadic awareness’ has not been sought for platyrrhine primates, although two platyrrhine genera, capuchins, Cebus, and squirrel monkeys, Saimiri, are among the most highly encephalized primates. We examined patterns of coalitionary recruitment in wild white-faced capuchins, C. capucinus. Analyses have shown that more dominant individuals are more likely to join aggressive coalitions than low-rankers, and that individuals preferentially support those with whom they have stronger affiliative relationships. Data from 110 fights, analysed using simulation techniques that produced distributions of results expected under null hypotheses, revealed that contestants preferentially solicited prospective coalition partners that (1) were dominant to their opponents, and (2) had better social relationships (higher ratios of affiliative/cooperative interactions to agonistic interactions) with themselves than with their opponents. Further analyses showed that soliciting dominant partners could be explained by either of two simpler rules, ‘Solicit an ally that outranks yourself’ or ‘Solicit the highest-ranking available individual’. However, soliciting partners with better social relationships appears to indicate triadic awareness, because subjects did not preferentially solicit the nearby individual with whom they shared the highest-quality social relationship. Effects of relative relationship quality on coalition solicitation decisions were independent of effects of dominance rank.     

The ontogeny of home ranges: evidence from coral reef fishes

The concept of home ranges is fundamental to ecology. Numerous studies have quantified how home ranges scale with body size across taxa. However, these relationships are not always applicable intraspecifically. Here, we describe how the home range of an important group of reef fish, the parrotfishes, scales with body mass. With masses spanning five orders of magnitude, from the early postsettlement stage through to adulthood, we find no evidence of a response to predation risk, dietary shifts or sex change on home range expansion rates. Instead, we document a distinct ontogenetic shift in home range expansion with sexual maturity. Juvenile parrotfishes displayed rapid home range growth until reaching approximately 100–150 mm length. Thereafter, the relationship between home range and mass broke down. This shift reflected changes in colour patterns, social status and reproductive behaviour associated with the transition to adult stages. While there is a clear relationship between body mass and home ranges among adult individuals of different species, it does not appear to be applicable to size changes within species. Ontogenetic changes in parrotfishes do not follow expected mass–area scaling relationships.     

Dominance status reversal based on pair-bond formation in the convict cichlid (Amatitlania nigrofasciata)

Dominant individuals have access to higher-quality resource; thus, reversing their dominance status would be important for subordinate individuals. Using the convict cichlid fish (Amatitlania nigrofasciata), this study examines whether forming a pair bond can reverse dominance status. Furthermore, I hypothesize that female convict cichlids will incur more dominance reversals from pair-bond formation than males. Dyadic, same-sex contests were conducted to determine dominant and subordinate individuals. Forced pairing of these individuals based on status was followed by polyadic, between-pair contests. The results indicate that individual dominance status does carry over into between-pair competition. Furthermore, dominance reversals do occur in convict cichlids and occur more frequently in females than in males. In addition, dominant males assist their mates during aggressive encounters, and these assists may account for subordinate females winning against dominant females during polyadic contests.     

The role of individual differences and patterns of resolution in the formation of dominance orders in domestic hen triads

This research compares the role of initial individual characteristics to that of patterns of resolution in which successive dominance relationships are established during the formation of triads in the domestic hen. Combining weight and comb size with prior victory or defeat in the site of encounter, we created three levels of asymmetries of characteristics for triads of hens. The effects of these asymmetries were then examined on the resultant hierarchies and on the order of conflict resolution within triads under two different conditions of assembly. In one condition (simultaneous triad), the three hens were simultaneously introduced to each other and could thus freely choose their opponent. In the other condition (step-assembled triad), the hen predicted to occupy the highest rank was left on standby and introduced once the other two hens had settled dominance. This condition disrupts the normal process of hierarchy formation by imposing the first sequence of dominance settlement. We found that the structure of triadic hierarchies can be predicted from individual characteristics existing prior to hierarchy formation. No difference in the resultant structures were found between conditions of introduction, though different paths of conflict resolution were followed indicating that individual differences had a more determining role on the resultant hierarchies than patterns of resolution. In addition to demonstrating that individual differences determine resultant triadic structures, the present results also show that the same end structures can be reached by following resolution paths that are not necessarily of the Double Dominance and Double Subordinance types as prescribed by Chase's model. It is also found that in the simultaneous condition hens select each other to form pairs. Therefore, individuals do not meet at random but choose each other as opponents. The two hens predicted from individual differences to occupy the highest ranks first settle dominance, followed by settlement between the winner of the previous encounter and the bystander.     

The behaviour associated with the occupation of breeding site in the kittiwake gull Rissa tridactyla: the social status of landing birds

A study of the landings of individually colour-ringed kittiwakes at nest sites showed that two functionally distinct categories of pre-and post-landing behaviour were adopted according to the social status (owner versus non-owner) of the landing bird with regard to the site in question. Almost all the occurrences where the behaviour of the adult was inconsistent with its social status were either due to a progressive development (or challenging) of the bird's status with respect to the landing site (56 cases), or the result of a conflicting situation (three cases). A diagram summarizing the behavioural stages in the ontogenetic process of acquiring site owner status (a fundamental stage in attaining breeding status) was established. It includes all the inconsistent situations observed. This shows that at every stage of the process the birds have different roles in the elaboration of the social environment of the colony.     

Response to social challenge in young bonnet (Macaca radiata) and pigtail (Macaca nemestrina) macaques is related to early maternal experiences

Previous experience affects how young primates respond to challenging social situations. The present retrospective study looked at one aspect of early experience, the quality of the mother-infant relationship, to determine its relationship to young bonnet and pigtail macaques' responses to two social challenges: temporary maternal separation at 5-6 months and permanent transfer to an unfamiliar peer group at 16-17 months. Relationship quality was measured quantitatively on 30 macaque mother-infant pairs with the Relationship Quality Index (RQI), the ratio of relative affiliation to relative agonism as previously applied to capuchin monkeys. Infants with high RQI values had amicable mother-infant relationships and infants with low RQI values had agonistic mother-infant relationships. Young monkeys with amicable and agonistic relationships showed consistent differences in behavior before, during, and after each social challenge, supporting the hypothesis that juveniles from amicable mother-infant relationships based on the RQI coped more effectively with social challenges than did juveniles from agonistic mother-infant relationships. Results suggest 1) characteristic amicability or agonism in early mother-offspring macaque relationships has the potential to influence offspring behavior in tense social contexts and 2) the RQI is useful as one of a coordinated suite of methods for studying the development of social skills.     

Coevolution of vocal communication and sociality in primates

Understanding the rules that link communication and social behaviour is an essential prerequisite for discerning how a communication system as complex as human language might have evolved. The comparative method offers a powerful tool for investigating the nature of these rules, since it provides a means to examine relationships between changes in communication abilities and changes in key aspects of social behaviour over evolutionary time. Here we present empirical evidence from phylogenetically controlled analyses indicating that evolutionary increases in the size of the vocal repertoire among non-human primate species were associated with increases in both group size and time spent grooming (our measure of extent of social bonding).     

Dynamic social behaviour in a bacterium: Pseudomonas aeruginosa partially compensates for siderophore loss to cheats

Cooperation underlies diverse phenomena including the origins of multicellular life, human behaviour in economic markets and the mechanisms by which pathogenic bacteria cause disease. Experiments with microorganisms have advanced our understanding of how, when and why cooperation evolves, but the extent to which microbial cooperation can recapitulate aspects of animal behaviour is debated. For instance, understanding the evolution of behavioural response rules (how should one individual respond to another's decision to cooperate or defect?) is a key part of social evolution theory, but the possible existence of such rules in social microbes has not been explored. In one specific context (biparental care in animals), cooperation is maintained if individuals respond to a partner's defection by increasing their own investment into cooperation, but not so much that this fully compensates for the defector's lack of investment. This is termed ‘partial compensation’. Here, I show that partial compensation for the presence of noncooperating ‘cheats’ is also observed in a microbial social behaviour: the cooperative production of iron‐scavenging siderophores by the bacterium Pseudomonas aeruginosa. A period of evolution in the presence of cheats maintains this response, whereas evolution in the absence of cheats leads to a loss of compensatory behaviour. These results demonstrate (i) the remarkable flexibility of bacterial social behaviour, (ii) the potential generality of partial compensation as a social response rule and (iii) the need for mathematical models to explore the evolution of response rules in multi‐player social interactions.     

Pair bonding in the wild mouse Mus spretus: inference on the mating system

The mating system of murids remains largely unknown, with controversial reports. Reevaluation of previous data reveals monogamous features in the Algerian mouse from the South of France, Mus spretus. To test this hypothesis, we performed dyadic encounters toward three kinds of opponents from the other sex (his/her own mate, a mouse from an unknown pair, and an isolated individual), and compared the results to those of a related acknowledgedly polygynous related species, the house mouse M. musculus domesticus. We expected more affiliative behaviours toward its mate from the M. spretus male, and a higher interest toward unknown females in the house mouse. Females should not exhibit striking differences toward their partner, contrary to their behaviour toward unknown males. Results showed the predicted behaviour for males as well as for females: more amicable, but also sexual, toward its mate for M. spretus male, the unknown protagonists eliciting the greatest social interest in the case of the house mouse.     

The Right Time to Happen: Play Developmental Divergence in the Two Pan Species

Bonobos, compared to chimpanzees, are highly motivated to play as adults. Therefore, it is interesting to compare the two species at earlier developmental stages to determine how and when these differences arise. We measured and compared some play parameters between the two species including frequency, number of partners (solitary, dyadic, and polyadic play), session length, and escalation into overt aggression. Since solitary play has a role in developing cognitive and physical skills, it is not surprising that chimpanzees and bonobos share similar developmental trajectories in the motivation to engage in this activity. The striking divergence in play developmental pathways emerged for social play. Infants of the two species showed comparable social play levels, which began to diverge during the juvenile period, a ‘timing hotspot’ for play development. Compared to chimpanzees, social play sessions in juvenile bonobos escalated less frequently into overt aggression, lasted longer, and frequently involved more than two partners concurrently (polyadic play). In this view, play fighting in juvenile bonobos seems to maintain a cooperative mood, whereas in juvenile chimpanzees it acquires more competitive elements. The retention of juvenile traits into adulthood typical of bonobos can be due to a developmental delay in social inhibition. Our findings show that the divergence of play ontogenetic pathways between the two Pan species and the relative emergence of play neotenic traits in bonobos can be detected before individuals reach sexual maturity. The high play motivation showed by adult bonobos compared to chimpanzees is probably the result of a long developmental process, rooted in the delicate transitional phase, which leads subjects from infancy to juvenility.     

繁殖期高原鼠兔的攻击行为

通过室内配对实验对高原鼠兔（Ｏｃｈｏｔｏｎａ ｃｕｒｚｏｎｉａｅ）繁殖期的攻击行为进行了研究。结果表明,雌雄动物的攻击水平相同,同性个体间的攻击性明显高于异性个体间。雌雄动物具有不同的攻击模式。雌性个体遇到陌生个体首先以攻击中的进攻和追逐为主,然后通过相互接触确定个体的性别,若为同性个体,以防御为主,若为异性个体,则有防御和亲昵两种选择;雄性动物遇到陌生个体同样首先以攻击为主,相互接触后,若为异性     

Inter-generational competition and selection for helping behaviour

A model is presented which considers the effects of inter-generational competition (IC) for breeding status on selection for helping behaviour. The model shows that for species with both high inter-generational overlap and high frequency of breeding opportunities within the individual's lifespan, helping behaviour is selected if the relatives raised by the helper through helping (i.e. present indirect fitness gains) do not decrease the helper's future direct fitness as a breeder. This effect is dependent on the value of α, the coefficient of IC. The occurrence of high α values can explain those cases in which a non-breeding member of a social group does not help. The effect of α can be reduced by means of establishing an age-based queueing system to attain breeding status. The breeders' acceptance of a non-helping individual within their territory may be explained as extended parental care or parental facilitation.     

Androgens, aggressive behaviour and social relationships in higher mammals

This paper reviews the relationships between androgen levels, aggressive behaviour and social relationships in ungulates and primates. In these and most other mammalian species, aggressive behaviour is sexually dimorphic with males being generally more aggressive than females. This difference is evident very early in play behaviour. In males, and sometimes also in females, aggressive behaviour varies in relation with reproductive cycles and the hormonal changes which are involved in these cycles. The experimental manipulation of hormonal levels by castration or administration of exogenous hormones gives results that vary according to the species, sex, type of hormone (e.g. aromatizable or non-aromatizable androgens), and other factors (e.g. antlers state in stags). Nevertheless, it has generally been shown that aggressive behaviour in male ungulates depends largely on androgens and that in female ungulates androgen treatment consistently raises social rank, with or without modification in aggressiveness. Primates, on the other hand, seem to be less dependent on androgens for the expression of aggressive behaviour and social status.     

Social interactions of juvenile Collared peccaries, Tayassu tajacu (Mammalia: Artiodactyla)

Is there a predictable relationship between species-typical behavioural development and social organization in mammals? Earlier work on canids and rodents suggested that adult sociality is associated with a developmental schedule in which juveniles showed, among themselves: (1) frequent social play; (2) frequent amicable contact; (3) frequent olfactory contact; (4) a delay in the emergence of agonistic behaviour. In the highly social Collared peccary (Tayassu tajacu) the behaviour of juveniles conformed only partially to this scheme. Juveniles engaged in social play with each other at an early age, but showed no other observable amicable or olfactory contact until eight to twelve weeks of age and showed no delay in the emergence of agonistic behaviour among themselves. Adults, in contrast, were conspicuously tolerant of juveniles, and 86% of juvenile social interactions in the first year took place with adults.     

Assessing the cost of helping: the roles of body condition and oxidative balance in the Seychelles warbler (Acrocephalus sechellensis)

In cooperatively breeding species, helping close relatives may provide important fitness benefits. However, helping can be energetically expensive and may result in increased generation of reactive oxygen species. Consequently, an oxidant/antioxidant imbalance can lead to higher oxidative stress susceptibility. Given the potential costs of helping, it may be that only individuals with a sufficiently good body condition and/or stable oxidative balance can afford to help. Knowledge about relationships between social status and oxidative balance in cooperatively breeding systems is still limited. Studying these relationships is important for understanding the costs of helping and physiological pressures of reproduction. Here we evaluate the relationship between helping behaviour, body condition and oxidative balance in a wild population of the cooperatively breeding Seychelles warbler (Acrocephalus sechellensis). In this species, some subordinate individuals help dominant birds with the rearing of young, while others refrain from any assistance. We assessed body condition and oxidative parameters of birds of different social status caught during different breeding stages. We found that, prior to breeding, female subordinates that did not subsequently help (non-helpers) had significantly lower body condition and higher ROMs (reactive oxygen metabolites) than helpers and dominants. During the later stages of breeding, body condition was low in dominants and helpers, but high in non-helpers. Differences in oxidative balance between individuals of different social status were found only during nest care: Dominant males occupied with guarding behaviours tended to have relatively high oxidative stress susceptibility. Furthermore, dominant and helper females showed elevated antioxidant capacity (measured as OXY) in the weeks just prior to egg-laying, possibly representing a change in their reproductive physiology. The results imply that an individuals' oxidative balance may be influenced by factors related to reproduction, which can differ with sex and--within cooperative breeding systems--social status.     

The dining etiquette of desert baboons: the roles of social bonds, kinship, and dominance in co-feeding networks

To better understand how individual relationships influence patterns of social foraging in primate groups, we explored networks of co-feeding in wild desert baboons (Papio ursinus). To minimize the risk of aggression and injury associated with contest competition, we expected that individual group members would choose to co-feed with those group-mates that are most likely to show tolerance and a willingness to share food patches. We tested two alternative hypotheses about who those group-mates might be: the "social bonds hypothesis" predicts that preferred foraging partners will be those with whom individuals share strong social bonds, indexed by grooming, whereas the "kinship hypothesis" predicts that preferred foraging partners will be relatives. We also investigated and controlled for the effects of dominance rank, given that competitive ability is known to shape foraging patterns. Social network analyses of over 5,000 foraging events for 14 adults in a single troop revealed that baboon co-feeding was significantly correlated with grooming relationships but not genetic relatedness, and this finding was also true of the female-only co-feeding network. Dominant individuals were also found to be central to the co-feeding network, frequently sharing food patches with multiple group-mates. This polyadic analysis of foraging associations between individuals underlines the importance of dominance and affiliation to patterns of primate social foraging.     

Persistent social interactions beget more pronounced personalities in a desert-dwelling social spider

The social niche specialization hypothesis predicts that repeated social interactions will generate social niches within groups, thereby promoting consistent individual differences in behaviour. Current support for this hypothesis is mixed, probably because the importance of social niches is dependent upon the ecology of the species. We test whether repeated interactions among group mates generate consistent individual differences in boldness in the social spider, Stegodyphus dumicola. In support of the social niche specialization hypothesis, we found that consistent individual differences in boldness increased with longer group tenure. Interestingly, these differences took longer to appear than in previous work suggesting this species needs more persistent social interactions to shape its behaviour. Recently disturbed colonies were shyer than older colonies, possibly reflecting differences in predation risk. Our study emphasizes the importance of the social environment in generating animal personalities, but also suggests that the pattern of personality development can depend on subtle differences in species'' ecologies.