scholarly journals Concessions of an alpha male? Cooperative defence and shared reproduction in multi-male primate groups

2012 ◽  
Vol 279 (1743) ◽  
pp. 3788-3795 ◽  
Author(s):  
Noah Snyder-Mackler ◽  
Susan C. Alberts ◽  
Thore J. Bergman
Keyword(s):  
Natural Variation ◽  
Social Groups ◽  
Reproductive Skew ◽  
Evolution Of Cooperation ◽  
Mutual Benefit ◽  
Adult Males ◽  
Alpha Male ◽  
Access To Resources ◽  
Theropithecus Gelada ◽  
Data Support

By living in social groups with potential competitors, animals forgo monopolizing access to resources. Consequently, debate continues over how selection might favour sociality among competitors. For example, several models exist to account for the evolution of shared reproduction in groups. The ‘concession model’ hypothesizes that dominant reproducers benefit from the presence of subordinates, and hence tolerate some reproduction by subordinates. This mutual benefit to both dominants and subordinates may provide a foundation for the formation of social groups in which multiple members reproduce—a necessary step in the evolution of cooperation. To date, however, the concession model has received virtually no support in vertebrates. Instead, the vast majority of vertebrate data support ‘limited control models’, which posit that dominant reproducers are simply unable to prevent subordinates from reproducing. Here we present the most comprehensive evidence to date in support of the concession model in a vertebrate. We examined natural variation in the number of adult males in gelada ( Theropithecus gelada ) reproductive units to assess the extent of reproductive skew in multi-male units. Dominant (‘leader’) males in units that also had subordinate (‘follower’) males had a 30 per cent longer tenure than leaders in units that did not have followers, mainly because followers actively defended the group against potential immigrants. Follower males also obtained a small amount of reproduction in the unit, which may have functioned as a concession in return for defending the unit. These results suggest that dominants and subordinates may engage in mutually beneficial reproductive transactions, thus favouring male–male tolerance and cooperation.

Access to Formal Credit in the Indian Agriculture: Does Caste matter?

2018 ◽  
Vol 4 (2) ◽  
pp. 169-195
Author(s):  
Karthick V. ◽  
Madheswaran S.
Keyword(s):  
Large Scale ◽  
Descriptive Analysis ◽  
Social Groups ◽  
Critical Factor ◽  
Credit Market ◽  
Access To Resources ◽  
Access To Credit ◽  
Indian Agriculture ◽  
Discrimination Coefficient ◽  
Lower Castes

Access to resources and opportunities can be a critical factor in improving outcomes for disadvantaged groups. Improving access to financial resources, in particular, is widely acknowledged to facilitate upward economic and social mobility. Conversely, lack of access to resources for certain groups based on caste, class, gender and ethno-social identities can perpetuate inequalities. In this context, this paper attempts to analyse the access to credit by social groups and decomposes the gross credit differentials using Oaxaca-blinder decomposition method using unit-level data from the All India Debt and Investment Survey, NSSO, 2013. The descriptive analysis clearly shows that there is a significant credit differential between forward caste (FC) and other social groups (SC, ST and OBC). Access to credit varies across social groups based on many factors. The decomposition result indicates that the discrimination coefficient against SC is 49per cent which explains that SCs are being discriminated by 49 per cent compared to FCs in the formal credit market. In case of ST, the discrimination coefficient against is 61per cent and for OBC it is 48per cent. Interestingly, the endowment difference is less among ST (38per cent) compared to SC and OBC (around 51 per cent). Also, the FC treatment advantage (benefit of being a FC in the credit market) is 5.7 per cent whereas the cost of being an SC in the credit market (treatment disadvantage) is 35.1 per cent. As expected, the disadvantage component for ST and OBC is 33.1 per cent and 17.8 per cent respectively. Thus, we see that although programmes, schemes and policies to promote the economic empowerment of lower castes through finance have been implemented on a large scale since the 1990s, they have not been very effective.

scholarly journals Offspring and adult chemosensory recognition by an amphisbaenian reptile may allow maintaining familiar links in the fossorial environment

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10780
Author(s):  
José Martín ◽  
Ernesto Raya-García ◽  
Jesús Ortega ◽  
Pilar López
Keyword(s):  
Parental Care ◽  
Chemical Cues ◽  
Kin Recognition ◽  
Social Groups ◽  
Tongue Flick ◽  
Adult Males ◽  
Stable Family ◽  
Males And Females ◽  
Family Groups

Kin recognition is a phenomenon with an important function in maintaining cohesive social groups in animals. Several studies have examined parent–offspring recognition in species with direct parental care. Few studies have, however, explored parent–offspring recognition in animals that, at best, only show apparent indirect parental care, such as some reptiles. In this study, we investigated reciprocal parent–offspring recognition in the fossorial amphisbaenian Trogonophis wiegmanni, a viviparous species that shows potential stable ‘family groups’ in the form of parent-offspring long-term associations. We examined whether adult males and females could discriminate via chemical cues between familiar juveniles which associate with them within their family groups, and are potentially their offspring, to that of unfamiliar juveniles, and whether juveniles could discriminate between familiar adult males and females of their family group (probably their parents) and unfamiliar unrelated adults. We measured tongue flick behavior to study chemosensory responses to the scent of conspecifics. We found that adult female amphisbaenians, but not males, could discriminate between scents of familiar and unfamiliar juveniles. Juvenile amphisbaenians did not discriminate between familiar and unfamiliar adult females, but recognize familiar from unfamiliar males. We discuss our results of parent–offspring recognition according to its potential social function in an ecological fossorial context where visibility is limited and chemosensory kin recognition may contribute to the establishment of stable family groups.

An uneasy alliance: unequal distribution of affiliative interactions among members of a captive wolf pack

2003 ◽  
Vol 81 (10) ◽  
pp. 1763-1766 ◽  
Author(s):  
Traci Cipponeri ◽  
Paul Verrell
Keyword(s):  
Canis Lupus ◽  
Social Groups ◽  
Alpha Male ◽  
Social Disruption ◽  
Unequal Distribution ◽  
Gray Wolves ◽  
Individual Fitness ◽  
Play Interactions ◽  
The Social ◽  
Time Of Breeding

The social groups of many vertebrates may be characterized as "uneasy alliances" that reflect tensions between benefits of group membership and costs to individual fitness among members, especially nonrelatives. The prebreeding season may be a time when these tensions become most acute and so observable for packs of gray wolves (Canis lupus). We recorded affiliative (play) interactions among two females and five males of known social ranks in a captive pack as the time of breeding approached. Substantial inequalities among pairs of wolves were apparent in frequencies of both the initiation of play and the exhibition of positive responses by recipient wolves. With the subsequent arrival of the breeding season, the pack experienced social disruption that led to the eviction of the original alpha male and a reordering of the ranks of those wolves remaining. Our data suggest that unequal affiliative interactions among pack members can be associated with (and, perhaps, even be predictive of) subsequent social disruption at a time when opportunities for personal reproduction become most available.

Peak occurrence of female sexual initiation predicts day of conception in rhesus monkeys (Macaca mulatta)

2000 ◽  
Vol 12 (8) ◽  
pp. 397 ◽  
Author(s):  
Julia L. Zehr ◽  
Pamela L. Tannenbaum ◽  
Benjamin Jones ◽  
Kim Wallen
Keyword(s):  
Rhesus Monkeys ◽  
Social Groups ◽  
Group Living ◽  
Sexual Initiation ◽  
Adult Males ◽  
Non Invasive ◽  
Sexual Solicitation ◽  
Delivery Date ◽  
Conception Date ◽  
Highly Correlated

The present study investigated whether peaks in female sexual initiation could accurately predict conception in group-living female rhesus monkeys. Behavioral observations, 4 or 5 days per week in large, stable, social groups of monkeys, provided frequencies of female initiation of proximity, sexual solicitation, mounts, and ejaculations. Since a preovulatory peak in female sexual initiation is likely linked to the preovulatory oestradiol surge, we used the third day after a peak in behavior as the behavioral estimate of conception date. For each pregnancy, an independent estimate of conception date was derived from ultrasound determination of fetal length. Estimates of conception based on female initiation of proximity with adult males were accurate for more than 90% of pregnancies, whereas observation of ejaculations by males predicted conception in fewer than 60% of pregnancies. Behavioral and ultrasound estimates of conception date were highly correlated and differed by less than 1 day on average. Accordingly, predictions of delivery date based on behavioral estimates of conception date were as accurate as those based on ultrasound-derived estimates. These data suggest that female-initiated sexual behavior can be used in rhesus monkeys as a practical, non-invasive tool for producing timed matings in social groups of monkeys, providing accurate estimates of conception date, gestational age, and predicted date of birth.

scholarly journals Long distance runners in the marine realm: New insights into genetic diversity, kin relationships and social fidelity of Indian Ocean male sperm whales

2021 ◽  
Author(s):  
Justine Girardet ◽  
Francois Sarano ◽  
Gaëtan Richard ◽  
Paul Tixier ◽  
Christophe Guinet ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Social Groups ◽  
Sperm Whale ◽  
Adult Males ◽  
Sperm Whales ◽  
Distance Runners ◽  
Long Distance ◽  
Male Sperm ◽  
Marine Realm ◽  
The Indian Ocean

AbstractAdult male sperm whales (Physeter macrocephalus) are long distance runners of the marine realm, feeding in high latitudes and mating in tropical and subtropical waters where stable social groups of females and immatures live. Several areas of uncertainty still limit our understanding of their social and breeding behaviour, in particular concerning the potential existence of geographical and/or social fidelities.In this study, using underwater observation and sloughed-skin sampling, we looked for male social fidelity to a specific matrilineal sperm whale group near Mauritius. In addition, we captured a wider picture of kin relationships and genetic diversity of male sperm whales in the Indian Ocean thanks to biopsies of eight unique individuals taken in a feeding ground near the Kerguelen and Crozet Archipelagos (Southern Indian Ocean).Twenty-six adult male sperm whales, of which 13 were sampled, were identified when socializing with adult females and immatures off Mauritius. Long-term underwater observation recorded several noteworthy social interactions between adult males and adult females and/or immatures. We identified seven possible male recaptures over different years (three by direct observation, and four at the gametic level), which supports a certain level of male social fidelity. Several first- and second-degree kin relationships were highlighted between members of the social unit and adult males, confirming that some of the adult males observed in Mauritian waters are reproductive. Male social philopatry to their natal group can be excluded, as none of the males sampled shared the haplotype characteristic of the matrilineal social group. Mitochondrial DNA control region haplotype and nucleotide diversities calculated over the 21 total male sperm whales sampled were similar to values found by others in the Indian Ocean.Our study strongly supports the existence of some levels of male sperm whale social fidelity, not directed to their social group of birth, in the Indian Ocean. Males sampled in breeding and feeding grounds are linked by kin relationships. Our results support a model of male mediated gene flow occurring at the level of the whole Indian Ocean, likely interconnected with large-scale geographical fidelity to ocean basin, and a small-scale social fidelity to matrilineal social groups.

scholarly journals Competition over guarding in the Arabian babbler (Turdoides squamiceps), a cooperative breeder

F1000Research ◽  
2015 ◽  
Vol 4 ◽  
pp. 618 ◽  
Author(s):  
Arnon Dattner ◽  
Amotz Zahavi ◽  
Avishag Zahavi
Keyword(s):  
Reproductive Success ◽  
Adult Female ◽  
Rift Valley ◽  
Adult Males ◽  
Alpha Male ◽  
Dominance Relationships ◽  
Direct Fitness ◽  
Previous Level ◽  
Arabian Babbler ◽  
The Way

Observations on 12 groups comprised of two adult males and one adult female (some included one or two fledglings), tame, individually marked, Arabian babblers (Turdoides squamiceps) in the rift valley in Israel revealed that the babblers compete to guard. The pattern of guarding and the way by which one sentinel replaces another reflect the dominance relationships within the group. The dominant (alpha) male guarded more than any other individual. It interfered with and replaced the guarding by the adult beta male more than it did with the yearlings. About one-third of the replacements occurred less than one minute after the sentinel had assumed guarding. Whereas the dominant often replaced its subordinates directly; subordinates hardly ever replaced their dominants directly. The alpha male often allofed the beta male during the replacement. Replacements and allofeeding of the beta males by the alpha males increased significantly during courtship, when competition over breeding was maximal, and dropped back to their previous level at the start of incubation, highlighting the competitive basis underlying the act of guarding. Competition over altruistic acts, as shown here for guarding, is not compatible with explanations based on the assumption that altruistic acts reduce the fitness (reproductive success) of the altruist. We suggest, in contrast, that by investing in guarding and by intervening in the guarding of its competitors, a babbler demonstrates and signals its quality and its control over its competitors, thereby increasing its prestige and consequently its direct fitness.

scholarly journals Atypically High Reproductive Skew in a Small Wild Chimpanzee Community in a Human-Dominated Landscape

2020 ◽  
Vol 91 (6) ◽  
pp. 688-696 ◽  
Author(s):  
Maureen S. McCarthy ◽  
Jack D. Lester ◽  
Marie Cibot ◽  
Linda Vigilant ◽  
Matthew R. McLennan
Keyword(s):  
Reproductive Success ◽  
Pan Paniscus ◽  
Reproductive Skew ◽  
Primate Species ◽  
Male Reproductive Success ◽  
Wild Chimpanzee ◽  
Anthropogenic Pressure ◽  
Small Community ◽  
Alpha Male ◽  
Community Size

Social rank is positively correlated with reproductive success in numerous species, albeit demographic factors often influence those patterns. In multimale primate species, reproductive skew tends to decrease with increasing numbers of males and sexually receptive females. Alpha male chimpanzees (<i>Pan troglodytes</i>) often sire a disproportionate, though somewhat variable, percentage of offspring compared to other males. In a small community of eastern chimpanzees inhabiting a human-dominated landscape in Bulindi, Uganda, we found extraordinarily high levels of alpha male reproductive success over a 5-year period (7/8 offspring = 88%), despite the presence of multiple subordinate males. The skew exceeds that reported in other studies of chimpanzees as well as closely related bonobos (<i>Pan paniscus</i>). Our findings underscore the role of demographic and social factors in male reproductive success and also suggest that conclusions about species differences may be premature. The interaction of small community size, dispersal limitations, and male reproductive strategies like those found here may decrease genetic diversity and increase the risk of concomitant inbreeding in chimpanzee communities under strong anthropogenic pressure.

Social Relationships Among Adult Male and Female Baboons. Ii. Behaviour Throughout the Female Reproductive Cycle

Behaviour ◽  
1978 ◽  
Vol 64 (3-4) ◽  
pp. 227-247 ◽  
Author(s):  
Robert M. Seyfarth
Keyword(s):  
Social Interactions ◽  
High Frequency ◽  
Focal Point ◽  
Low Frequency ◽  
Social Bond ◽  
Adult Males ◽  
Alpha Male ◽  
Subordinate Male ◽  
Two Factors ◽  
Pregnancy And Lactation

AbstractA study of social interactions between two adult males and eight adult females throughout sexual cycling, pregnancy, and lactation revealed three types of "long-term" social bond. 1. Persistent, high-frequency bonds. Two male-female dyads exhibited frequent proximity and grooming throughout the study regardless of changes in female reproductive state. In both cases frequent interaction persisted because of preferences which partners showed for each other. Males in both dyads aided their partners when the partners received aggression more often than they aided others. 2. Persistent, low-frequency bonds. Three females showed a preference for the Alpha male over the subordinate male in all reproductive states. Each female appeared to be attempting to establish a "high-frequency" social bond with the Alpha male. However, all were prevented from doing so by two factors: the Alpha male's preference for one female over all others (see above), and competition from this preferred female. Females competed for access to the Alpha male equally often in all reproductive states. 3. Bonds based on "alternating" f emale preference. Three females associated primarily with the subordinate male during lactation and the Alpha male during sexual cycling. Since the subordinate male served as a focal point for the activities of infants and juveniles, females appeared to benefit from their association with him during lactation. In addition, data suggested that the subordinate male, having established bonds during lactation, attempted to maintain these bonds into the females' periods of sexual cycling. It is hypothesized that the existence of these male-female bonds in multi-male primate groups produces a social structure characterized by a polygynous mating system. Data suggest that male-female relationships are best understood not by examining sexual consortship alone but by considering sexual behaviour within the context of social interactions throughout all reproductive states.

The Demographic and Reproductive Context of Male Replacements in Cebus Capucinus

Behaviour ◽  
2004 ◽  
Vol 141 (6) ◽  
pp. 755-775 ◽  
Author(s):  
Katharine Jack ◽  
Linda Marie Fedigan
Keyword(s):  
Group Composition ◽  
Study Groups ◽  
Cebus Capucinus ◽  
Lower Proportion ◽  
Adult Males ◽  
Alpha Male ◽  
Term Study ◽  
Annual Peak ◽  
Long Term Study

AbstractMale primates may immigrate into groups by peacefully joining the residents and taking up low-ranking positions in the hierarchy, or they may enter by force, challenging the resident males and attempting to drive them from high rank or from the group. Here we address the questions of how, when, and why immigrating male white-faced capuchins (C. capucinus) at Santa Rosa replace the former resident males of our groups, rather than simply joining them. We present data on 15 male replacements in 6 study groups tracked from 1984 through March 2004. During 11 aggressive takeovers, resident males were nearly always outnumbered by coalitions of invading males; lone resident males were particularly vulnerable. Both residents and invaders were wounded and infants often perished during or soon after takeovers. Male replacements also occur when resident males abandon their groups and males from neighboring groups 'waltz in' to become resident. Three such 'waltz in' replacements occurred during the study period. If we combine takeovers with 'waltz in' cases, replacements occur about every 4 years in our study groups, almost invariably during the dry season months of January to April, about 3-6 months before the annual peak in conceptions. In the years that groups are subject to takeovers, group composition includes significantly lower proportions of adult males than in no-takeover years. We conclude that: (1) the mechanism of male replacement is usually aggressive takeover, but sometimes abandonment of the group by prior resident males occurs; and (2) aggressive takeovers are more likely to happen when the group is vulnerable because it has a lower proportion of adult males, particularly when all co-resident males have emigrated, leaving only the alpha male in residence. Our long-term study shows that adult males need coalition partners not only to gain entry to a group but also to maintain their membership within it.

scholarly journals Object carrying as socio-sexual display in an aquatic mammal

2008 ◽  
Vol 4 (3) ◽  
pp. 243-245 ◽  
Author(s):  
A.R Martin ◽  
V.M.F da Silva ◽  
P Rothery
Keyword(s):  
Social Groups ◽  
Sexually Dimorphic ◽  
Adult Males ◽  
Isolated Populations ◽  
Aquatic Mammal ◽  
Sexual Display ◽  
Adult Females ◽  
River Bed ◽  
Inia Geoffrensis ◽  
Dimorphic Species

Amazon river dolphins or botos ( Inia geoffrensis Blainville) were observed carrying objects in 221 social groups over a 3-year study period. Sticks, branches and clumps of grass were taken from the water surface and often repeatedly thrashed or thrown. Lumps of hard clay were collected from the river bed and held in the mouth while the carrier rose slowly above the surface and submerged again. Carriers were predominantly adult males and less often subadult males. Adult females and young dolphins rarely carried objects. Groups of dolphins in which object carrying occurred were differentially large and comprised a greater proportion of adult males and adult females. Aggression, mostly between adult males, was significantly associated with object carrying. The behaviour occurred year-round, with peaks in March and July. A plausible explanation of the results is that object carrying by adult males is aimed at females and is stimulated by the number of females in the group, while aggression is targeted at adult males and is stimulated by object carrying in the group. We infer that object carrying in this sexually dimorphic species is socio-sexual display. It is either of ancient origin or has evolved independently in several geographically isolated populations.

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