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1.
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.  相似文献   

2.
True recognition of kin can have important fitness consequences in terms of directing altruistic behaviours toward close relatives (nepotism) and avoiding inbreeding. However, recent evidence suggests that some social insect species cannot or do not distinguish their closest relatives from among nestmates in important fitness-based contexts. Such findings are relevant to kin selection theories where individuals are expected to preferentially rear close relatives in order to gain inclusive fitness benefits. Here, allozyme markers are used to examine whether female Exoneura robusta individuals preferentially nest with their closest kin when given a choice of familiar previous nestmates. The results suggest these bees do not prefer kin over non-kin nestmates. Kin associations during nest founding in this species are probably due to philopatry and/or association with previously familiar nestmates.  相似文献   

3.
Kinship and sociality in coastal river otters: are they related?   总被引:1,自引:0,他引:1  
Previous studies of coastal river otters (Lontra canadensis)in Prince William Sound, Alaska, USA, documented atypical socialorganization for mammals. Social groups were composed largelyof males, but some males remained solitary year-round and mostfemales were asocial. Because, in carnivores, groups are usuallycomposed of highly related individuals but group living alsoprovides advantages unrelated to kinship, we concurrently evaluatedthe role of relatedness and ecological benefits in socialityamong coastal river otters. By using DNA microsatellite analysisand radiotelemetry, we were able to reject the hypothesis thatsocial groups of otters were kin based. In addition, we foundno indication of kin avoidance, as would be expected from lowdispersal and high local competition. Sociality conferred noreproductive benefits or costs to otters; number of offspringand number of relatives in the population did not differ betweensocial and solitary animals. Solitary males were not older orlarger than were social males, and there was no relation betweenmale size and number of offspring, indicating that sexual selectiondid not mask a potential relation between sociality and reproductivesuccess. Among coastal river otters in this region, socialitycould be explained by the benefits obtained from cooperativeforaging on high-quality schooling pelagic fishes. Such benefitsdid not require association with kin, resulting in no selectionpressure for kin-based groups. The prediction that the degreeof sociality in the population will fluctuate relative to theabundance of schooling pelagic fishes merits further investigation.  相似文献   

4.
Kin recognition in Bufo scaber tadpoles: ontogenetic changes and mechanism   总被引:1,自引:0,他引:1  
Ontogenetic changes in kin-recognition behavior, effect of social environment on kin-recognition ability, and use of visual and chemical cues in kin recognition have been studied in tadpoles of Bufo scaber after rearing them with kin, in mixed groups, or in isolation from Gosner stage 12 (gastrula). By use of a rectangular choice tank the tadpoles were tested for their ability to choose between (a) familiar siblings and unfamiliar non-siblings, (b) unfamiliar siblings and familiar non-siblings, and (c) unfamiliar siblings and unfamiliar non-siblings. When tested without any stimulus groups in the end compartments of the tank, random distribution was observed for the tadpoles and no bias for the apparatus or the procedure. In the presence of kin and non-kin in the end compartments, significantly more tadpoles spent most of their time near kin (familiar or unfamiliar) rather than near non-kin during early larval stages, up to stage 37. After stage 37 (characterized by the differentiation of toes), test tadpoles showed no preference to associate with kin, suggesting an ontogenetic shift in the kin-recognition ability in B. scaber. In experiments involving selective blockade of visual or chemical cues the test tadpoles preferentially associated near their kin on the basis of chemical rather than visual cues. These findings suggest that familiarity with siblings is not necessary for kin recognition and that kin-recognition ability is not modified after exposure to non-kin by mixed rearing. The findings for B. scaber indicate a self referent phenotype matching mechanism of kin recognition which is predominantly aided by chemical rather than visual cues.  相似文献   

5.
Ecology is a fundamental driving force for the evolutionary transition from solitary living to breeding cooperatively in groups. However, the fact that both benign and harsh, as well as stable and fluctuating, environments can favour the evolution of cooperative breeding behaviour constitutes a paradox of environmental quality and sociality. Here, we propose a new model – the dual benefits framework – for resolving this paradox. Our framework distinguishes between two categories of grouping benefits – resource defence benefits that derive from group‐defended critical resources and collective action benefits that result from social cooperation among group members – and uses insider–outsider conflict theory to simultaneously consider the interests of current group members (insiders) and potential joiners (outsiders) in determining optimal group size. We argue that the different grouping benefits realised from resource defence and collective action profoundly affect insider–outsider conflict resolution, resulting in predictable differences in the per capita productivity, stable group size, kin structure and stability of the social group. We also suggest that different types of environmental variation (spatial vs. temporal) select for societies that form because of the different grouping benefits, thus helping to resolve the paradox of why cooperative breeding evolves in such different types of environments.  相似文献   

6.
Can information sharing explain recruitment to food from communal roosts?   总被引:4,自引:0,他引:4  
The debate over whether communal nests and roosts function primarilyas information centers (they facilitate the sharing of foraginginformation) remains unresolved. Here I use evolutionary gametheory to investigate the relative importance of this influentialhypothesis and an alternative: that roosts, in particular,function as recruitment centers (they facilitate aggregationat food patches). Basing my model on juvenile common raven (Corvus corax) behavior, I assume there is no net cost to beingat food patches in groups, and foragers roost communally. Moreover,one strategic outcome is the observed raven behavior: individualssearch independently and recruit from the roost once a patchis found (they play Search-and-Recruit, or SR). I investigatethe stability of this in two scenarios that differ in the magnitudeof the lost opportunity costs to mutants playing SR in populations of other strategies. When these costs only involve a chanceof not being in a group at a located carcass, SR is the onlyevolutionarily stable strategy under all conditions. However,when these costs also include missing opportunities to be sociallydominant, SR no longer enjoys exclusive dominance in the strategyset. Nevertheless, in both cases, there are conditions where group foraging benefits have no effect on the evolutionary stabilityof SR. Thus, contrary to assertions in the literature, theopportunity to share foraging information can be sufficientto drive the evolution and maintenance of recruitment to foodfrom communal roosts. However, I conclude that both informationand grouping benefits are likely to underlie communal roostingbehavior in my focal system.  相似文献   

7.
The ontogeny of kin recognition and influence of social environment on the development of kin recognition behaviour was experimentally investigated in tadpoles of Bufo melanostictus that lived in aggregations and showed low larval dispersion. Embryos and tadpoles of the toad were reared as (i) kin only, (ii) with kin and non-kin (separated by a mesh screen), and (iii) in isolation. They were tested for the ability to discriminate between (i) familiar siblings and unfamiliar non-siblings, (ii) familiar siblings and familiar non-siblings and, (iii) unfamiliar siblings and unfamiliar non-siblings. All tadpoles were fed on boiled spinach before conducting trials. Preference of test tadpoles to associate near the end compartments whether empty or containing members of specific stimulus groups was assessed using a rectangular choice tank. When tested in tanks with empty end compartments, the test tadpoles showed random distribution and thus no bias for the apparatus or the procedure. In the presence of kin/non-kin in the end compartments a significantly greater number of test tadpoles spent the majority of the time near familiar or unfamiliar kin rather than near familiar or unfamiliar non-kin. Kin discrimination ability persisted throughout larval development. Familiarity with siblings is not required for discriminating kin from non-kin, and kin discrimination ability is not modified following exposure to non-kin. Also, involvement of dietary cues is unlikely to be the prime mechanism of kin recognition inB. melanostictus unlike in some other anurans.  相似文献   

8.
Association preferences and aggression intensity were investigated in relation to kin and familiarity in the self-fertilizing, clonal vertebrate, the mangrove killifish Kryptolebias marmoratus. Results indicated that fish preferentially associated with and exhibited less intense aggression towards members of their own genotype (kin), compared to members of a different genotype (non-kin). Furthermore, when fish were presented with stimulus groups of the same genotype that were familiar or unfamiliar, fish preferentially associated with and exhibited lower aggression intensity directed towards familiar groups. These results indicate that this species prefer to associate with both kin and familiar individuals and modulate aggression accordingly. These results are discussed with reference to the adaptive benefits of kin recognition and preferences for familiars, and place results within the context of current knowledge of the ecology of K. marmoratus.  相似文献   

9.
Unless a safe refuge is found where predation threats are negligible,resting poses risks for many animals, necessitating risk managementstrategies. The adult cowtail stingray (Pastinachus sephen)of Shark Bay, Western Australia, is a solitarily foraging animalthat facultatively groups when resting on shallow, inshore sandflats. We hypothesized that environmental conditions influencethe propensity of cowtails to group due to the limited abilityto detect predators visually in certain conditions. We thenexplored the possible benefits of grouping, such as bodily protection,early warning, and predator confusion, in conjunction with potentialgrouping costs, such as increased interference when initiatingflight and decreased escape speeds. Our study revealed thatin poor underwater visibility (due to turbidity and/or low ambientlight levels), cowtails primarily rest in small groups (threerays). Tests of flight initiation distance to a mock predatordemonstrated that solitary cowtail escape distances are significantlyshorter in poor than in good underwater visibility conditions.As to grouping benefits, filmed boat transects revealed thatcowtails most often arrange themselves in a rosette position,possibly as a means to protect their bodies and expose theirtails. The first cowtail in a group initiates flight to a mockpredator at a significantly greater distance than a solitarycowtail, and grouped cowtails escape an approaching boat ina significantly more cohesive manner than a simulated groupof escaping individual rays. Grouped cowtails exhibit behaviorsthat would impede immediate flight after detection. As a result,grouped rays escape a boat at significantly slower speeds thansolitary cowtails. Results from this study demonstrate thatthe interplay between costs and benefits of grouped and solitaryresting under differing environmental conditions is driven bydifferences in perceived predation risk and ultimately reflectedin the facultative grouping behavior of this species.  相似文献   

10.
Neolamprologus pulcher is a cooperatively breeding cichlid fish,in which helpers stay in their natal territory and help withbrood care, territory defense, and maintenance. In this studywe investigated helper effects by an experimental group sizereduction in the field. After this manipulation, focal helpersin reduced groups tended to feed less, and small helpers visitedthe breeding shelter significantly more often than same-sizedhelpers in control groups. No evidence was found that remaininghelpers compensated for the removed helpers by increasing territorydefense and maintenance behavior. Breeders, however, did showa lower defense rate, possibly caused by an increase in broodcare effort. Survival of fry was significantly lower in removalthan control groups, which provides the first experimental proofin a natural population of fish that brood care helpers do effectivelyhelp. The data suggest that in small, generally younger, helpers,kin selection may be an important evolutionary cause of cooperation.Large helpers, however, who are generally older and less relatedto the breeders than small helpers are suggested to pay to beallowed to stay in the territory by helping. All group membersbenefit from group augmentation.  相似文献   

11.
In group living species, individuals may gain the indirect fitness benefits characterizing kin selection when groups contain close relatives. However, tests of kin selection have primarily focused on cooperatively breeding and eusocial species, whereas its importance in other forms of group living remains to be fully understood. Lekking is a form of grouping where males display on small aggregated territories, which females then visit to mate. As females prefer larger aggregations, territorial males might gain indirect fitness benefits if their presence increases the fitness of close relatives. Previous studies have tested specific predictions of kin selection models using measures such as group‐level relatedness. However, a full understanding of the contribution of kin selection in the evolution of group living requires estimating individuals' indirect fitness benefits across multiple sites and years. Using behavioural and genetic data from the black grouse (Tetrao tetrix), we show that the indirect fitness benefits of group membership were very small because newcomers joined leks containing few close relatives who had limited mating success. Males' indirect fitness benefits were higher in yearlings during increasing population density but marginally changed the variation in male mating success. Kin selection acting through increasing group size is therefore unlikely to contribute substantially to the evolution and maintenance of lekking in this black grouse population.  相似文献   

12.
Preferences for grouping with familiar individuals are shown in many animal species, including the three-spined stickleback (Gasterosteus aculeatus). Shoaling with familiars is advantageous because of more precise anti-predator behaviours or more stable dominance hierarchies. Additionally, associations with familiar individuals facilitate the evolution of altruistic behaviour. Thus, in situations of increased competition one might expect an increased preference for familiar fish. We gave single juvenile sticklebacks of different nutritional state the choice between shoals composed either of familiar or unfamiliar individuals. Satiated fish preferred to shoal with familiar individuals. A comparative analysis of 8 stickleback studies with 15 different tests using familiars showed that all tests gave similar results, i.e. sticklebacks of all age classes preferred to shoal with familiars in a non-sexual context. In contrast, hungry test fish did not prefer to shoal with familiar fish, but even showed a preference for the unfamiliar group. Because sticklebacks use early-life familiarity to recognize kin, the results suggest the avoidance of competition with relatives. To our knowledge, this is the first study showing an impact of nutritional state on social interactions with familiar individuals.  相似文献   

13.
For more than ten years, reproductive biotechnologies using somatic cell nuclear transfer have made possible the production of cloned animals in various domestic and laboratory species. The influence of the cloning process on offspring characteristics has been studied in various developmental aspects, however, it has not yet been documented in detail for behavioral traits. Behavioral studies of cloned animals have failed to show clear inter-individual differences associated with the cloning process. Preliminary results showed that clones favor each other's company. Preferential social interactions were observed among cloned heifers from the same donor in a mixed herd that also included cloned heifers and control heifers produced by artificial insemination (AI). These results suggest behavioral differences between cloned and non-cloned animals and similarities between clones from the same donor. The aim of the present study was to replicate and to extend these previous results and to study behavioral and cognitive mechanisms of this preferential grouping. We studied a group composed of five cloned heifers derived from the same donor cow, two cloned heifers derived from another donor cow, and AI heifers. Cloned heifers from the same donor were more spatially associated and interacted more between themselves than with heifers derived from another donor or with the AI individuals. This pattern indicates a possible kin discrimination in clones. To study this process, we performed an experiment (using an instrumental conditioning procedure with food reward) of visual discrimination between images of heads of familiar heifers, either related to the subjects or not. The results showed that all subjects (AI and cloned heifers) discriminated between images of familiar cloned heifers produced from the same donor and images of familiar unrelated heifers. Cattle discriminated well between images and used morphological similarities characteristic of cloned related heifers. Our results suggest similar cognitive capacities of kin and non kin discrimination in AI and cloned animals. Kinship may be a common factor in determining the social grouping within a herd.  相似文献   

14.
Kin selection theory has been the central model for understanding the evolution of cooperative breeding, where non-breeders help bear the cost of rearing young. Recently, the dominance of this idea has been questioned; particularly in obligate cooperative breeders where breeding without help is uncommon and seldom successful. In such systems, the direct benefits gained through augmenting current group size have been hypothesized to provide a tractable alternative (or addition) to kin selection. However, clear empirical tests of the opposing predictions are lacking. Here, we provide convincing evidence to suggest that kin selection and not group augmentation accounts for decisions of whether, where and how often to help in an obligate cooperative breeder, the chestnut-crowned babbler (Pomatostomus ruficeps). We found no evidence that group members base helping decisions on the size of breeding units available in their social group, despite both correlational and experimental data showing substantial variation in the degree to which helpers affect productivity in units of different size. By contrast, 98 per cent of group members with kin present helped, 100 per cent directed their care towards the most related brood in the social group, and those rearing half/full-sibs helped approximately three times harder than those rearing less/non-related broods. We conclude that kin selection plays a central role in the maintenance of cooperative breeding in this species, despite the apparent importance of living in large groups.  相似文献   

15.
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.  相似文献   

16.
We examined aggressive behavior in Siberian jay groups containingboth retained offspring and immigrant juveniles during winterfeeding and during breeding. Selective tolerance of retainedoffspring by parental birds in winter suggests that cooperationevolved through kin selection. Parents exhibited a self-restraintin aggression towards retained offspring at food in winter.Comparatively, nonkin immigrants were aggressively preventedfrom sharing food by the local pair. Parental tolerance in wintercould bring inclusive fitness gains through the direct kin componentif retained offspring experience relaxed competition and enhancedsurvival. Parental tolerance would then favor the evolutionof delayed dispersal. There is no evidence that delayed dispersalamong Siberian jays should have evolved because of indirectfitness benefits to retained offspring from helping to raiseyounger siblings. Offspring retained by parents did not participatein incubation, feeding or nest defense.  相似文献   

17.
Many animals modify their behavior toward unfamiliar conspecifics as a function of their genetic relatedness. A fundamental problem of any kin recognition study is determining what is being recognized and why. For anuran tadpoles, the predominant view is that associating with relatives is kin-selected because these relatives may thereby accrue benefits through increased growth or predation avoidance. An alternative view is that kin associations are simply a side-effect of habitat selection and thus do not represent attempts to identify kin per se. In the laboratory, spadefoot toad tadpoles (Scaphiopus multiplicatus) preferentially associated with unfamiliar siblings over unfamiliar nonsiblings, as do other anurans. However, same age tadpoles also were more likely to orient toward unfamiliar nonsiblings reared on the same food (familiar food) than toward unfamiliar siblings that were reared on unfamiliar food. These results, together with the results of previous tadpole kin recognition studies, suggest that tadpoles orient toward cues learned early in ontogeny, regardless of the cues' source. Tadpoles that preferentially associated with cues learned from their environment at birth would tend to be philopatric. Censuses of 14 natural ponds revealed that tadpole density remained greatest near oviposition sites until four days before metamorphosis. Tadpole philopatry may be advantageous: tadpoles restricted to their natal site had greater growth and survivorship than did their siblings restricted to randomly selected sites elsewhere within the same pond. Thus kin affiliative tendency observed in the laboratory in this and perhaps other species of anurans may be a byproduct of habitat selection. Since kin discrimination in animals is most commonly assayed as orientation toward kin, it follows that many examples of “kin recognition” may not represent true attempts to identify kin as such, but rather may reflect some other recognition system that is under entirely different selective pressures.  相似文献   

18.
Cooperative alliances among kin may not only lead to indirect fitness benefits for group-living species, but can also provide direct benefits through access to mates or higher social rank. However, the immigrant sex in most species loses any potential benefits of living with kin unless immigrants disperse together or recruit relatives into the group in subsequent years. To look for evidence of small subgroups of related immigrants within social groups (kin substructure), we used microsatellites to assess relatedness between immigrant females of the cooperatively breeding superb starling, Lamprotornis superbus. We determined how timing of immigration led to kin subgroup formation and if being part of one influenced female fitness. Although mean relatedness in groups was higher for males than females, 26% of immigrant females were part of a kin subgroup with a sister. These immigrant sibships formed through kin recruitment across years more often than through coalitions immigrating together in the same year. Furthermore, females were more likely to breed when part of a kin subgroup than when alone, suggesting that female siblings form alliances that may positively influence their fitness. Ultimately, kin substructure should be considered when determining the role of relatedness in the evolution of animal societies.  相似文献   

19.
I determined whether grouping behavior influences parasite loadand body temperature of Galápagos marine iguanas, reptilesthat rest gregariously. Mobile (or predatory) Ornithodoros ticks(4.7 mm average body length) approached at a ground speed of65 cm/min and parasitized sleeping marine iguanas for 3.7 hper night, drawing about 0.1 ml blood. Contagiously transmittedAmblyomma ticks hang on to iguana hosts for days or weeks. Marineiguanas sleeping alone had 2.0 mobile ticks per night, whileindividuals sleeping in groups had 0.1 to 1.1 mobile ticks pernight. Single iguanas decreased their mobile parasite load to0.2 ticks per night by sleeping on bushes. Experimental nightlytranslocation of iguanas to areas without other sleeping iguanassignificantly increased their mobile parasite burden above levelsencountered by naturally single individuals (n = 4.6 ticks pernight). Creating an experimental group of two animals reducedinfestation with mobile ticks by 59% compared to levels on singleanimals. Over the course of weeks, mobile ectoparasite loadsat grouping sites increased to levels found at single sites,at which point marine iguanas changed sleeping sites. Groupinghad no effect on the prevalence of contagious ticks. Furthermore,grouping did not help to conserve body temperature in Genovesaiguanas, as measured by radiotelemetry. I conclude that marineiguanas group during daytime at microhabitats favored for thermoregulation(predation is absent in this population). Thermoregulation wasnot of prime importance for nightly aggregations, which insteadserved to reduce mobile ectoparasite load. As a minimum costof infestation, I estimate that individuals sleeping alone wouldhave a 5.4% lower annual energy budget due to tissue removal,not including potential internal infections.  相似文献   

20.
Dispersal patterns are important in metapopulation ecology because they affect the dynamics and survival of populations. However, because little empirical information exists on dispersal behaviour of individuals, theoretical models usually assume random dispersal. Recent empirical evidence, by contrast, suggests that the butterfly Maniola jurtina uses a non‐random, systematic dispersal strategy, can detect and orient towards habitat from distances of 100–150 m, and prefers a familiar habitat patch over a non‐familiar one (‘homing behaviour’). The present study (1) investigated whether these results generalise to another butterfly species, Pyronia tithonus; and (2) examined the cause of the observed ‘homing behaviour’ in M. jurtina. P. tithonus used a similar non‐random, systematic dispersal strategy to M. jurtina, had a similar perceptual range for habitat detection and preferred a familiar habitat patch over a non‐familiar one. The ‘homing behaviour’ of M. jurtina was found to be context‐dependent: individual M. jurtina translocated within habitat did not return towards their capture point, whereas individuals translocated similar distances out of habitat did return to their ‘home’ patch. We conclude that butterfly ‘homing behaviour’ is not based on an inherent preference for a familiar location, but that familiarity with an area facilitates the recognition of suitable habitat, towards which individuals orient if they find themselves in unsuitable habitat. Contrary to conventional wisdom, we suggest that frequent, short ‘excursions’ over habitat patch boundaries are evolutionarily advantageous to individuals, because increased familiarity with the surrounding environment is likely to increase the ability of a straying animal to return to its natural habitat, and to reduce the rate of mortality experienced by individuals attempting to disperse between habitat patches. We discuss the implications of the non‐random dispersal for existing metapopulation models, including models of the evolution of dispersal rates.  相似文献   

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