Natural endocrine profiles of the group-living skunk anemonefish Amphiprion akallopisos in relation to their size-based dominance hierarchy

2018 ◽  
Vol 92 (3) ◽  
pp. 773-789 ◽  
Author(s):  
S. C. Mills ◽  
J. L. O'Donnell ◽  
G. Bernardi ◽  
R. Beldade
Keyword(s):  
Dominance Hierarchy ◽  
Group Living ◽  
Endocrine Profiles ◽  
Amphiprion Akallopisos

scholarly journals Non-random associations in group housed rats (Rattus norvegicus)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Leanne Proops ◽  
Camille A. Troisi ◽  
Tanja K. Kleinhappel ◽  
Teresa Romero
Keyword(s):  
Network Analysis ◽  
Empirical Evidence ◽  
Rattus Norvegicus ◽  
Dominance Hierarchy ◽  
Group Living ◽  
Ecological Factors ◽  
Limited Evidence ◽  
Rat Strains ◽  
Social Species ◽  
Over Time

AbstractEcological factors, such as predation, have traditionally been used to explain sociability. However, it is increasingly recognised that individuals within a group do not associate randomly, and that these non-random associations can generate fitness advantages. The majority of the empirical evidence on differentiated associations in group-living mammals, however, comes from a limited number of taxa and we still know very little about their occurrence and characteristics in some highly social species, such as rats (Rattus spp.). Here, using network analysis, we quantified association patterns in four groups of male fancy rats. We found that the associations between rats were not randomly distributed and that most individuals had significantly more preferred/avoided associates than expected by random. We also found that these preferences can be stable over time, and that they were not influenced by individuals’ rank position in the dominance hierarchy. Our findings are consistent with work in other mammals, but contrast with the limited evidence available for other rat strains. While further studies in groups with different demographic composition are warranted to confirm our findings, the occurrence of differentiated associations in all male groups of rats have important implications for the management and welfare of captive rat populations.

scholarly journals Social dominance and cooperation in female vampire bats

2021 ◽  
Vol 8 (7) ◽  
pp. 210266
Author(s):  
Rachel J. Crisp ◽  
Lauren J. N. Brent ◽  
Gerald G. Carter
Keyword(s):  
Dominance Hierarchy ◽  
Social Rank ◽  
Group Living ◽  
Experimental System ◽  
Food Sharing ◽  
Competitive Interactions ◽  
Female Dominance ◽  
Cooperative Relationships ◽  
Vampire Bats ◽  
In The Wild

When group-living animals develop individualized social relationships, they often regulate cooperation and conflict through a dominance hierarchy. Female common vampire bats have been an experimental system for studying cooperative relationships, yet surprisingly little is known about female conflict. Here, we recorded the outcomes of 1023 competitive interactions over food provided ad libitum in a captive colony of 33 vampire bats (24 adult females and their young). We found a weakly linear dominance hierarchy using three common metrics (Landau's h ’ measure of linearity, triangle transitivity and directional consistency). However, patterns of female dominance were less structured than in many other group-living mammals. Female social rank was not clearly predicted by body size, age, nor reproductive status, and competitive interactions were not correlated with kinship, grooming nor food sharing. We therefore found no evidence that females groomed or shared food up a hierarchy or that differences in rank explained asymmetries in grooming or food sharing. A possible explanation for such apparently egalitarian relationships among female vampire bats is the scale of competition. Female vampire bats that are frequent roostmates might not often directly compete for food in the wild.

scholarly journals Protogyny in a tropical damselfish: females queue for future benefit

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2198 ◽  
Author(s):  
Mark I. McCormick
Keyword(s):  
Dominance Hierarchy ◽  
Nest Site ◽  
Group Living ◽  
Trade Offs ◽  
Pomacentrus Amboinensis ◽  
Reproductive Male ◽  
The Cost ◽  
Removal Studies ◽  
Linear Dominance Hierarchy

Membership of the group is a balance between the benefits associated with group living and the cost of socially constrained growth and breeding opportunities, but the costs and benefits are seldom examined. The goal of the present study was to explore the trade-offs associated with group living for a sex-changing, potentially protogynous coral reef fish, the Ambon damselfish,Pomacentrus amboinensis. Extensive sampling showed that the species exhibits resource defence polygyny, where dominant males guard a nest site that is visited by females.P. amboinensishave a longevity of about 6.5 years on the northern Great Barrier Reef. While the species can change sex consistent with being a protogynous hermaphrodite, it is unclear the extent to which the species uses this capability. Social groups are comprised of one reproductive male, 1–7 females and a number of juveniles. Females live in a linear dominance hierarchy, with the male being more aggressive to the beta-female than the alpha-female, who exhibits lower levels of ovarian cortisol. Surveys and a tagging study indicated that groups were stable for at least three months. A passive integrated transponder tag study showed that males spawn with females from their own group, but also females from neighbouring groups.In situbehavioural observations found that alpha-females have priority of access to the nest site that the male guarded, and access to higher quality foraging areas. Male removal studies suggest that the alpha-females can change sex to take over from the male when the position becomes available. Examination of otolith microstructure showed that those individuals which change sex to males have different embryonic characteristics at hatching, suggesting that success may involve a component that is parentally endowed. The relative importance of parental effects and social organisation in affecting the importance of female queuing is yet to be studied, but will likely depend on the strength of social control by the dominant members of the group.

scholarly journals Breeding displacement in gray wolves (Canis lupus): Three males usurp breeding position and pup rearing from a neighboring pack in Yellowstone National Park

2021 ◽  
Author(s):  
Jeremy SunderRaj ◽  
Jack W. Rabe ◽  
Kira A. Cassidy ◽  
Rick McIntyre ◽  
Daniel R. Stahler ◽  
...  
Keyword(s):  
Canis Lupus ◽  
Yellowstone National Park ◽  
National Park ◽  
Dominance Hierarchy ◽  
Group Living ◽  
Female Mate Choice ◽  
Gray Wolves ◽  
Adult Females ◽  
Dominant Female ◽  
Territorial Group

Gray Wolves (Canis lupus) are territorial, group living carnivores that live in packs typically consisting of a dominant breeding pair and their offspring. Breeding tenures are relatively short and competitive, with vacancies usually occurring following a breeder’s death, and are often filled by unrelated immigrants or by relatives of the previous breeder. The frequency and conditions of active breeder displacements are poorly understood. Position changes in the dominance hierarchy are common yet rarely documented in detail. We describe a turnover in male breeding position in a wolf pack by males from a neighboring pack in mid-summer 2016 in Yellowstone National Park. Over the course of two months, three males from the Mollie’s pack displaced the breeding male of the neighboring Wapiti Lake pack, joined the pack’s two adult females, and subsequently raised the previous male’s four approximately three-month old pups. In the four years following the displacement (2017 to 2020), at least one of the intruding males has successfully bred with the dominant female and most years with a subordinate female (who was one of the pups at the time of displacement). The pack reared pups to adulthood each year. Male breeding displacements are likely influenced by male-male competition and female mate choice. These changes are the result of individuals competing to improve breeding position and may lead to increased pack stability and greater reproductive success. We report in detail on the behavior of a closely observed breeding displacement and we discuss the adaptive benefits of the change.

scholarly journals Boldness traits, not dominance, predict exploratory flight range and homing behaviour in homing pigeons

2017 ◽  
Vol 372 (1727) ◽  
pp. 20160234 ◽  
Author(s):  
Steven J. Portugal ◽  
Rhianna L. Ricketts ◽  
Jackie Chappell ◽  
Craig R. White ◽  
Emily L. Shepard ◽  
...  
Keyword(s):  
Dominance Hierarchy ◽  
Morphological Characteristics ◽  
Group Living ◽  
Columba Livia ◽  
Local Area ◽  
Homing Pigeons ◽  
Laboratory Conditions ◽  
Novel Objects ◽  
Spontaneous Exploration ◽  
The Individual

Group living has been proposed to yield benefits that enhance fitness above the level that would be achieved through living as solitary individuals. Dominance hierarchies occur commonly in these social assemblages, and result, by definition, in resources not being evenly distributed between group members. Determinants of rank within a dominance hierarchy can be associated with morphological characteristics, previous experience of the individual, or personality traits such as exploration tendencies. The purpose of this study was to investigate whether greater exploration and positive responses to novel objects in homing pigeons ( Columba livia ) measured under laboratory conditions were associated with (i) greater initial exploration of the local area around the home loft during spontaneous exploration flights (SEF), (ii) faster and more efficient homing flights when released from further afield, and (iii) whether the traits of greater exploration and more positive responses to novel objects were more likely to be exhibited by the more dominant individuals within the group. There was no relationship between laboratory-based novel object exploration and position within the dominance hierarchy. Pigeons that were neophobic under laboratory conditions did not explore the local area during SEF opportunities. When released from sites further from home, neophobic pigeons took longer routes to home compared to those birds that had not exhibited neophobic traits under laboratory conditions, and had spontaneously explored to a greater extent. The lack of exploration in the neophobic birds is likely to have resulted in the increased costs of homing following release: unfamiliarity with the landscape likely led to the greater distances travelled and less efficient routes taken. Birds that demonstrated a lack of neophobia were not the dominant individuals inside the loft, and thus would have less access to resources such as food and potentially mates. However, a lack of neophobia makes the subordinate position possible, because subordinate birds that incur high travel costs would become calorie restricted and lose condition. Our results address emerging questions linking individual variation in behaviour with energetics and fitness consequences. This article is part of the themed issue ‘Physiological determinants of social behaviour in animals’.

Leaders of spontaneous group movements influence whole-group social organization: an experimental study on grazing heifers

Behaviour ◽  
2013 ◽  
Vol 150 (2) ◽  
pp. 153-173 ◽  
Author(s):  
Lia Della-Rossa ◽  
Joël Chadœuf ◽  
Alain Boissy ◽  
Bertrand Dumont
Keyword(s):  
Social Organization ◽  
Dominance Hierarchy ◽  
Group Living ◽  
Heterogeneous Environments ◽  
Group Leaders ◽  
Social Traits ◽  
The Stability ◽  
The Individual ◽  
Group Compositions ◽  
Group Movements

Group-living animals have to reach consensus decisions through recruitment processes while collectively exploiting food resources in heterogeneous environments. In farming conditions, the group compositions are frequently modified, which can force the animals to readjust their collective strategies, e.g., when group leaders are removed. We, therefore, conducted a group-manipulation experiment for testing how the loss of the individual with the highest leadership score in spontaneous group movements is likely to influence decision-making and whole-group social organization. Observations were carried out in two groups of nine familiar heifers, as using animals of the same age-class simplifies the analysis of the proximate determinants of leadership. Under the hypothesis of distributed leadership, we expected the emergence of a new leader but no change in social relationships due to the stability of dominance hierarchy and affinities among the familiar remaining heifers. Both group leaders were heifers that had a low cohesion index and expressed few allogrooming interactions. Leadership did not relate to position in the dominance hierarchy. After removing the leader and replacing it with a familiar peer, the number of spontaneous group movements decreased by 40% in both groups, and no new leader emerged. Both groups maintained a structure after leader removal but the distribution of pairwise association was modified. Allogrooming interactions dropped by nearly 60% in one group and their overall distribution were modified in the other group. These findings demonstrate interrelations between various social traits — even in the case of same-age herbivore groups — and difficulties with rapidly reaching a new consensus for maintaining synchronized activity and group cohesion.

Subjective Fear Dilutes as Group Size Increases

2020 ◽  
Author(s):  
dean mobbs ◽  
Ellen Tedeschi ◽  
Anastasia Buyalskaya ◽  
Brian Silston
Keyword(s):  
Group Size ◽  
Real World ◽  
Survival Benefit ◽  
Group Living ◽  
External Factors ◽  
Threat Perception ◽  
Perception Of Threat ◽  
Threat Level ◽  
Internal States ◽  
Risk Dilution

According to Hamilton’s Selfish Herd Theory, a crucial survival benefit of group living is that it provides a ‘risk dilution’ function against predation. Despite a large literature on group living benefits in animals, few studies have been conducted on how group size alters subjective fear or threat perception in humans, and on what factors drive preferences for being in groups when facing threats. We conducted seven experiments (N=3,838) to test (A) if the presence of others decreases perception of threat under a variety of conditions. In studies 1 to 3, we experimentally manipulated group size in hypothetical and real-world situations, to show that fear responses decreased as group size increased. In studies 4 to 7 we again used a combination of hypothetical, virtual and real-world decisions to test (B) how internal states (e.g. anxiety) and external factors (e.g. threat level, availability of help) affected participants’ preference for groups. Participants consistently chose larger groups when threat and anxiety were high. Overall, our findings show that group size provides a salient signal of protection and safety.

Affiliations, aggressions and an adoption: Male–male relationships in wild bonobos

2018 ◽  
Author(s):  
Martin Surbeck ◽  
Gottfried Hohmann
Keyword(s):  
Close Relationships ◽  
Group Living ◽  
Mate Competition ◽  
Male Group ◽  
Cooperative Hunting ◽  
Sexual Behaviours ◽  
Study Population ◽  
Living Species ◽  
The Way

The nature of the relationships between males is a characteristic trait of many multi-male group living species with implications for the individuals. In our study population of bonobos, certain male dyads exhibit clear preferences for ranging in the same party and sitting in proximity. These preferences are not reflected in the frequency of aggression towards each other and only to some extent in their affiliative and socio-sexual behaviours. While bonobo males at LuiKotale clearly do not benefit from close relationships in the way chimpanzee males do (cooperative hunting, territorial patrol, mate competition), some relationships might result from close associations between their mothers. In some particular situations, these male relationships can be very important as in the case of an orphan adopted by his older maternal brother. La nature des relations entre mâles est un trait caractéristique de plusieurs groupes qui ont plusieurs mâles, avec des implications au niveau d’individus. Dans notre étude des populations de bonobos, certains dyades mâles montrent une préférence à aller dans le même groupe et s’asseoir proche l’un de l’autre. Cette préférence n’est pas reflétée dans la fréquence d’agression entre eux et est seulement lié, à degrés, à leur comportements socio-sexuels et d’appartenance. Tandis que les mâles bonobos à LuiKotale ne profitent pas de leur fortes relations comme les chimpanzés mâles (chasse coopérative, patrouille territoriale, compétition pour compagnon), ils peuvent aider leur partenaires à supporter le stress de la vie en groupe et peuvent en conséquence contribuer au bien-être des individus. Quelques proches associations entre les mâles peuvent provenir d’associations entre leurs mères. Dans quelques situations particulières, ces relations mâles prouvent leur importance comme dans le cas d’un orphelin adopté par son grand frère maternel.

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