Dominance,kinship and reproductive value in female Barbary macaques (Macaca sylvanus) at Affenberg Salem

Summary In the course of a long-term study on social organization of semi-free-ranging Barbary macaques (Macaca sylvanus) at Affenberg Salem, genealogical and cross-genealogical rank relations of adult and adolescent females in three social groups were studied. Female rank was highly dependent on maternal rank, but the process of rank acquisition was also affected by age/size differences between members of different families. Mother-daughter rank reversal was rare, but all old, postreproductive matriarchs were outranked by their adult daughters. Contrary to findings of other studies on macaques, younger sisters seldom outranked older sisters. There was no genealogy with a strict age-inversed hierarchy among adult sisters as described for rhesus and Japanese macaques. Rank reversals between sisters were more frequent in genealogies with old or dead matriarchs, in large clans, and in dyads with an age difference of more than 1 year, indicating that demographic variables influence intra-genealogical dominance relations. It is suggested that close, long-lasting relationships between sisters and mothers and doughters impede rank reversals. Previous evolutionary models of female dominance relations in primates that explain rank relations among sisters as a function of their reproductive value or as a strategy of the mother to maintain her own status are not supported by the data. The results of this and other studies indicate that rank reversal between sisters is not as universal for Old World monkeys, or even macaques, as frequently proposed.     

Sex differences in fitness following a group take-over among Toque macaques: testing models of social evolution

Summary A group of toque macaques took-over the home range of one of its subordinate neighboring groups and fused with it to form a larger cohesive group. In the 7 years before the take-over, the dominant group had consistently won all contests at common feeding sites, yet the fitnesses of the females of these two groups did not differ significantly (Fig. 2A). After the take-over the females of the subjugated group occupied the lowest ranks in the combined dominance hierarchy of the merged groups (Fig. 1) and thereby lost the advantages of an own home range, such as priority of access to food. Consequently, in the merged group, survivorship and reproductive success among the subjugated females were significantly less than among the females of the dominant subgroup (Table 2, 4). The dominant matrilines grew numerically and replaced all of the subjugated females, and all but one of their offspring, within 8 years after the take-over (Fig. 2B). These data support the hypothesis that cooperation among female kin in defending resources against strange females is important in the evolution of female-bonded groups. Before the merger all 5 natal males of the subordinate group had transferred to the dominant group, where they occupied high and mid-level dominance ranks (Fig. 1). These males survived at a significantly greater rate than their subordinate female kin. Thus, the cost of group transfer seems to be greater for females than for males, and this may be one reason that females generally do not emigrate or that groups do not fuse. The data suggested three hypotheses. First, since large body size and other adaptations for fighting, giving males an advantage in male-male competition for mates, are also of advantage in resource competition with males and females, such male characters may also be favored by non-sexual selection, especially where male reproductive strategy involves group transfer. Second, female bonded groups evolved as female defensive coalitions against not only female but also male resource competitors, there having been a mutual influence in the coevolution of large-sized males and female gregariousness. Third, female defensive coalitions against large-sized aggressive males are also advantageous out-side the context of food competition, or, independent of foraging strategy.     

Colony fission affects kinship in a social insect

Establishment of new groups is an important step in the life history of a social species. Fissioning is a common mode not only in group proliferation, for instance, as a regular part of the life cycle in the honey bee, but also when multiple females reproduce in the same group, as in multiple-queen ant societies. We studied the genetic consequences of fissioning in the ant Proformica longiseta, based on DNA microsatellites. In P. longiseta, new nests arise by fissioning from the old ones when they grow large, and the daughter nests consist of workers and queens or queen pupae but never both. Our results show that fissioning is not entirely random with respect to kinship. Workers tend to segregate along kin lines, but only when the initial relatedness in the parental nests is low. Workers in a daughter nest also tend to be associated with closely related adult queens, whereas such an association is not detected between workers and queen pupae. Most queens and workers are carried to the daughter nest by a specialized group of transporting workers, suggesting active kin discrimination by them. Fissioning pattern in P. longiseta is different from that found in other social insects with regular fission (e.g., the honey bee, swarm-founding wasps), where no fissioning along kin lines has been found. It does, however, resemble fissioning in another group of social animals: primates.     

Communal nesting, kinship, and maternal success in a social primate

Communal nesting, where several mothers regularly pool and cooperatively rear offspring, is unusual in mammals. This type of crèching behavior is especially rare among primates, with the notable exceptions of humans, some nocturnal strepsirrhines, and—as we show in this study—black-and-white ruffed lemurs (Varecia variegata). Here, we combine data on nesting behavior, genetic relatedness, and infant survivorship to describe variation in ruffed lemur infant care and to examine the potential benefits of ruffed lemur communal breeding. Reproductive events were rare, and females produced litters (synchronously) only once in 6 years of observation. We show that not all mothers participate in communal crèches, but those that did had greater maternal success; communal breeders spent more time feeding and their offspring were more likely to survive. Although cooperating mothers were often related, females also cooperated with non-kin, and those who shared infant care responsibilities had greater maternal success than mothers who did not participate. If there is indeed a causal link between maternal cooperation and reproductive success, this unusual behavior, like that of human communal rearing, may have evolved via some combination of kin selection and mutualism.     

Effects of kinship on growth of a live-bearing reef fish

The influence of genetic relatedness on the individual performance (e.g. growth, development) of animals is often tied to agonistic or cooperative behaviors among conspecifics, and studies of the effects of kinship have produced mixed results. To explore genetic relatedness independent of these behaviors, we investigated the effects of kinship on the growth of the kelp perch Brachyistius frenatus, a live-bearing, planktivorous marine reef fish that is capable of only limited dispersal. Although juveniles occur in aggregations and compete for food resources, they do not exhibit overt aggressive or cooperative behavioral interactions. We hypothesized that under competition and in the absence of these behaviors, sibling and non-sibling groups of juvenile B. frenatus raised at the same densities in the field would not differ in average growth, but that siblings would exhibit lower variation in growth, simply due to genetic similarities in inherent growth rates. Pregnant, female kelp perch were collected and placed in cages until parturition was complete. Groups of young, recently born from the same mother or from different mothers, were then raised in the field for 9 wk. Our results revealed that average growth rates were similar between sibling and non-sibling treatments. While variation in growth increased initially in non-siblings, siblings showed little such variation. This divergence, however, was not consistent over the duration of the experiment, and variation in the growth of siblings ultimately converged with that of non-siblings. Effects of genetic relatedness would be most likely to manifest themselves early after birth, before environmental factors exert their influence, and this may explain the initial separation but eventual convergence in variation in growth between sibling and non-sibling treatments. For B. frenatus and other organisms that will encounter relatives and compete for resources without overt behavioral interactions, the degree of kinship may play a minor role in the demography of local populations. Received: 26 January 1998 / Accepted: 30 September 1998     

The influence of kinship on foraging competition in Siberian jays

Foraging competition in Siberian jay groups was examined in relation to dominance and kinship to determine whether juvenile offspring, by associating with adults, gained in food acquisition relative to juvenile immigrants. Members of the adult pair were dominant over juvenile cohort members and males were dominant to females, although an inter-sexual hierarchy, with male juveniles occasionally overlapping adult females, was suggested. Few competitive asymmetries were found between adults and retained offspring or adults and immigrant juveniles when they were competing for food together, but in kin and non-kin foraging groups, respectively. Male offspring visited the bait site more frequently than adult males, and female immigrants spent less time at the bait site than adult females. Under these circumstances, hoarding activities may limit the ability of alpha members to control resources. In mixed groups containing both juvenile offspring and juvenile immigrants, no difference was found in the number of visits made to the bait site, although load sizes and foraging rates were lower for immigrant birds. Retained juveniles obtained greater load sizes and foraging rates when associating with adults. The social dominance of parents suggests that they control juvenile foraging. Although offspring benefit in the presence of adults, adults may incur a cost to their restraint by spending more time at the bait site when competing with immigrants. These results extend conclusions from previous work describing the role of selective tolerance by adults which relaxes competition with retained offspring in Siberian jay winter groups. The present findings suggest that offspring benefit in both immediate and future energy gains, which may have a direct influence on survival. Received: 18 September 1996 / Accepted after revision: 26 January 1997     

Influence of kinship on helping behavior in Galápagos mockingbirds

Summary The social organization of the Galápagos mockingbird (Nesomimus parvulus) in unusual in that groups frequently include more than one breeding pair (plural breeding), and helping behavior is flexible: some birds neither breed nor help, while others do both. To investigate the influence of kinship on helping behavior, I categorized each bird as a helper or non-helper with respect to each nest within its group where it had an opportunity to help. The incidence of helping varied with relatedness: more birds helped when nestlings available to be fed were close relatives than when not. This result was independent of a higher incidence of helping among males than among females and of variation with age among males. Proportionally more nonbreeding than breeding males helped, but breeding and nonbreeding females helped equally infrequently; breeders helped most often after their own nests failed. The incidence of helping was highest among birds with opportunities to feed offspring of breeders that had fed the potential helper as a nestling, suggesting a mechanism for kin discrimination based on associative learning. Juveniles with opportunities to choose among alternative recipients preferentially fed closely related nestlings, but insufficient information was available to determine if adults also did so. Kinship did not influence the rate at which nestlings were fed by helpers. Juveniles fed nestlings at lower rates than did adult helpers, but helping effort was otherwise unaffected by age, sex, or relatedness. Limitation of help to former feeders functions as a mechanism for directing aid to relatives in a plural breeding system where degrees of kinship vary among potential recipients within the same group.     

Cooperation in breeding by nonreproductive wrens: kinship,reciprocity, and demography

Summary Stripe-backed wrens (Campylorhynchus nuchalis) often live as adults in large groups on permanent, communally defended territories. Nonbreeding adults cooperate in rearing the young of a single breeding pair; this aid substantially increases the reproductive success of the breeders. In a 6-year study in Venezuela of a completely colorbanded population of 25–30 groups, most adults participated in breeding only as helpers and priority to breeding status was strictly age-determined. Detailed behavioral observations at breeding nests with nestlings showed that, in a sample of 100, helpers nearly always contributed as much to the care of young as breeders. Further, aid-giving does not vary systematically with relatedness of ycung to helpers or with probability of future reciprocation by young. Young being raised are most often at least half siblings of helpers, but seldom return aid to adults that helped raise them. Even adopted helpers collaborate fully. Patterns of demography and dispersal show slow turnover of breeders, delayed reproduction, and a viscous population structure.Application of Hamilton's condition for selection for aid-giving reveals that most individuals in this population can maximize inclusive fitness in the first 2 years by helping instead of breeding. Variation in helping effort and in age of first breeding is related to variation in natal group size and competition resulting from variable demographic neighborhoods in different years or in different parts of the population. Because reciprocation in the form of specific alliance formation among nonreproductives is uncommon, nonspecific reciprocity between cohorts and kin selection account well for the observed pattern of age-dependence in first breeding. Nondiscriminating helping in this population is associated with stable monogamous pair boncs, stable territory boundaries and group membership, strict seniortiy for breeding position, high viscosity and consistent effectiveness of aid. Under these circumstances, very simple behavioral rules amounting to nearly automatic helping seem sufficient to confer critical inclusive fitness gain on helpers.     

Social dynamics of juvenile marmots: Role of kinship and individual variability

Summary A population of eight juvenile female yellow-bellied marmots (Marmota flaviventris) was introduced into a marmot locality from which all other marmots were removed. Social interactions were monitored in the field and the individual behavioral profile of each animal was determined by mirror image stimulation. Social interactions were unequally distributed among the eight juveniles. Neither body size nor kinship were significantly related to frequencies of social interactions. Social interactions were significantly related to individual differences.     

Foraging patterns of yellow-bellied marmosts: role of kinship and individual variability

Summary Two colonies of yellow-bellied marmots (Marmota flaviventris) at an elevation of 2900 m in Colorado were studied to elucidate the role of various behavioral and ecological factors as determinants of spatial foraging patterns. The locations of known individuals were periodically recorded. These locality data were plotted as three-dimensional block diagrams, the peak heights representing the frequency of observation. Predation risk and vegetation distribution influenced the location of foraging areas; kinship was an important factor in the determination of the amount of foraging area shared between individual marmots. Spatial overlap tended to be greater among close kin, but this was modified by individual behavioral characteristics, reproductive state, the existence of separate burrow systems within a colony, and the age of the animal. Mothers and juveniles, and littermates as young and resident yearlings, had nearly identical foraging areas.     

代谢活化作用对多溴代联苯类污染物类/抗甲状腺激素活性的影响

选用大鼠肝匀浆(S9)和鼠肝癌细胞(H4ⅡE)两种体系代谢活化多溴代联苯醚混标(BDEs)和十溴联苯醚(BDE209),采用重组甲状腺激素受体基因酵母检测BDEs和BDE209母体及其代谢产物的类/抗甲状腺激素效应.结果表明,BDEs和BDE209母体均不表现甲状腺激素效应(p>0.05);但是经S9和H4ⅡE细胞代谢活化后,其代谢产物表现出明显的类甲状腺激素活性和抗甲状腺激素活性(p<0.05),BDEs和BDE209的干扰甲状腺激素效应需要经过代谢活化步骤.比较不同代谢活化体系,重组酵母细胞本身的代谢活化作用并不显著,而H4ⅡE细胞和S9代谢活化体系均能够导致活性中间体.     

Spatial relationships and matrilineal kinship in African savanna elephant (Loxodonta africana) clans

African savanna elephants, Loxodonta africana, live in stable family groups consisting of adult females and their dependent offspring. During the dry season, clans consisting of several family groups typically share a common home range. We compared spatial relationships and mitochondrial DNA (mtDNA) haplotypes among 14 adult female elephants within 3 clans during the dry season in northern Zimbabwe. Spatial relationships were studied by radio-tracking. Home-range similarity was quantified by correlating the estimated utilization distributions of all pairs of elephants. Clans were identified by cluster analysis of the home-range similarity values. All three clans contained at least two of the five mtDNA haplotypes that were found, indicating that clan members are not necessarily matrilineally related. Within clans, home ranges of elephants with the same haplotype were not significantly more similar to each other than those of elephants with different haplotypes. Most elephants within each clan used their shared home ranges independently of each other: the distribution of distances between their positions at any given time did not differ from the distribution expected by chance. However, 8 out of the 26 within-clan pairs exhibited long-term coordination of space use by remaining within known hearing distance of each others low-frequency calls significantly more often than expected by chance. At least four of these coordinated pairs consisted of animals in different family groups. Elephants in three of the four different-family pairs whose movements were coordinated had different haplotypes. Further research is needed to determine the relationship between these coordinated movements and conventionally defined bond-group behavior.Electronic Supplementary Material Supplementary material is available in the online version of this article at .Communicated by C. Nunn     

Sequence of quorums during collective decision making in macaques

Synchronization of activity is one of the major challenges of any society, and to what extent social animals reach a consensus still remains to be established. In the case of group movements, recent studies have underlined the importance of the pre-departure period and suggested that some individuals in a group express their motivation to move by showing a preference for a specific direction. However, how do other group members really choose the time and direction of movement? This study shows that in two semi-free ranging Tonkean macaque (Macaca tonkeana) groups, several individuals propose different directions for movement by displaying unique behavior. The whole group eventually moves in the choice of direction supported by the majority of individuals according to a sequence of three quorum rules. Moreover, when the number of individuals choosing another direction is higher than their own group, individuals that proposed alternative directions eventually renounce and follow the majority. Despite conflict of interests, group members reach a consensus before the actual start of group movement. This demonstrates that processes of this type, which can be considered to be voting processes, are not exclusive to human societies and may be explained by a complex sequence of simple rules.     

Association patterns and kinship in female Indo-Pacific bottlenose dolphins (Tursiops aduncus) of southeastern Australia

Kinship has been shown to be an important correlate of group membership and associations among many female mammals. In this study, we investigate association patterns in female Indo-Pacific bottlenose dolphins (Tursiops aduncus) inhabiting an embayment in southeastern Australia. We combine the behavioral data with microsatellite DNA and mitochondrial DNA data to test the hypotheses that genetic relatedness and maternal kinship correlate with associations and social clusters. Mean association between females was not significantly different from a random mean, but the standard deviation was significantly higher than a random standard deviation, indicating the presence of nonrandom associates in the dataset. A neighbor-joining tree, based on the distance of associations between females, identified four main social clusters in the area. Mean genetic relatedness between pairs of frequent female associates was significantly higher than that between pairs of infrequent associates. There was also a significant correlation between mtDNA haplotype sharing and the degree of female association. However, the mean genetic relatedness of female pairs within and between social clusters and the proportion of female pairs with the same and different mtDNA haplotypes within and between clusters were not significantly different. This study demonstrates that kinship correlates with associations among female bottlenose dolphins, but that kinship relations are not necessarily a prerequisite for membership in social clusters. We hypothesize that different forces acting on female bottlenose dolphin sociality appear to promote the formation of flexible groups which include both kin and nonkin.     

Dominance, not kinship, determines individual position within the communal roosts of a cooperatively breeding bird

Kin selection has played an important role in the evolution and maintenance of cooperative breeding behaviour in many bird species. However, although relatedness has been shown to affect the investment decisions of helpers in such systems, less is known about the role that kin discrimination plays in other contexts, such as communal roosting. Individuals that roost communally benefit from reduced overnight heat loss, but the exact benefit derived depends on an individual's position in the roost which in turn is likely to be influenced by its position in its flock's dominance hierarchy. We studied the effects of kinship and other factors (sex, age, body size and flock sex ratio) on an individual's roosting position and dominance status in captive flocks of cooperatively breeding long-tailed tits Aegithalos caudatus. We found that overall, kinship had little influence on either variable tested; kinship had no effect on a bird's position in its flock's dominance hierarchy and the effect of kinship on roosting position was dependent on the bird's size. Males were generally dominant over females and birds were more likely to occupy preferred roosting positions if they were male, old and of high status. In this context, the effect of kinship on social interactions appears to be less important than the effects of other factors, possibly due to the complex kin structure of winter flocks compared to breeding groups.