Intergroup conflict: origins, dynamics and consequences across taxa

Philosophical Transactions of the Royal Society B Biological Sciences, Journal Year: 2022, Volume and Issue: 377(1851)

Published: April 4, 2022

Although uniquely destructive and wasteful, intergroup conflict warfare are not confined to humans. They seen across a range of group-living species, from social insects, fishes birds mammals, including nonhuman primates. With its unique collection theory, research review contributions biology, anthropology economics, this theme issue provides novel insights into taxa. Here, we introduce organize on the origins consequences conflict. We provide coherent framework by modelling conflicts as multi-level games strategy in which individuals within groups cooperate compete with (individuals in) other for scarce resources, such territory, food, mating opportunities, power influence. Within framework, identify cross-species mechanisms (participating conclude highlighting crosscutting innovations study set forth individual contributions. These include, among others, how within-group heterogeneities leadership relate group conflict, shapes organization climate change environmental degradation transition relations peaceful coexistence violent This article is part ‘Intergroup taxa’.

Language: Английский

---

Environmental stress increases out-group aggression and intergroup conflict in humans

Philosophical Transactions of the Royal Society B Biological Sciences, Journal Year: 2022, Volume and Issue: 377(1851)

Published: April 4, 2022

Peaceful coexistence and trade among human groups can be fragile intergroup relations frequently transition to violent exchange conflict. Here we specify how exogenous changes in groups' environment ensuing carrying-capacity stress increase individual participation conflict, out-group aggression particular. In two contest experiments, individuals could contribute private resources (versus in-group defense). Environmental unpredictability, induced by making non-invested subject risk of destruction not), created psychological increased coordination attacks. Archival analyses interstate conflicts showed, likewise, that sovereign states engage revisionist warfare more when their pre-conflict economic climatic were volatile unpredictable. Given conflict is wasteful, environmental unpredictability not only made often victorious but also less wealthy. Macro-level the natural a root cause turn benign violent. This article part theme issue ‘Intergroup across taxa’.

Language: Английский

---

Correlates of individual participation in boundary patrols by male chimpanzees

Philosophical Transactions of the Royal Society B Biological Sciences, Journal Year: 2022, Volume and Issue: 377(1851)

Published: April 4, 2022

Group territory defence poses a collective action problem: individuals can free-ride, benefiting without paying the costs. Individual heterogeneity has been proposed to solve such problems, as high in reproductive success, rank, fighting ability or motivation may benefit from defending territories even if others free-ride. To test this hypothesis, we analysed 30 years of data chimpanzees ( Pan troglodytes ) Kasekela community, Gombe National Park, Tanzania (1978–2007). We examined extent which individual participation patrols varied according correlates success (mating rate, age), (hunting), (scores personality ratings), costs defecting (the number adult males community) and gregariousness (sighting frequency). By contrast expectations theory, participated at consistently rates (mean ± s.d. = 74.5 11.1% patrols, n 23 males). The best predictors patrol were sighting frequency, age hunting participation. Current former alpha did not participate higher rate than that never achieved status. These findings suggest temptation free-ride is low, mutualistic mechanism group augmentation better explain territorial behaviour. This article part theme issue ‘Intergroup conflict across taxa’.

Language: Английский

---

Ecological Interactions Drive a Power‐Law Relationship Between Group Size and Population Density in Social Foragers

Ecology Letters, Journal Year: 2025, Volume and Issue: 28(4)

Published: April 1, 2025

Past work has shown that group formation in foraging animals aids resource acquisition and reduces the number of interactions with predators. However, can also increase competition for resources among members. Here, we model how individual costs benefits drive size. Our predicts when occurs within between groups, forager size will exhibit a one-third power-law relationship population abundance. if groups form due to intragroup predation, predict either one-half abundance or constant depending on coupling predator prey. Using empirical data birds ungulates, found scaling consistent power-law, suggesting hierarchical drives average results support highlighting importance density-dependent maintaining stability.

Language: Английский

---

Drivers and outcomes of between-group conflict in vervet monkeys

Philosophical Transactions of the Royal Society B Biological Sciences, Journal Year: 2022, Volume and Issue: 377(1851)

Published: April 4, 2022

Neighbouring groups compete over access to resources and territories in between-group encounters, which can escalate into conflicts (BGCs). Both the ecological characteristics of a territory rival's fighting ability shape occurrence outcome such contests. What remains poorly understood, however, is how seasonal variability value together with related likelihood encounters extent these conflicts. To test this, we observed followed four vervet monkey wild, recorded group structure (i.e. size, composition), locations outcomes 515 BGCs. We then assessed key measures at locations, as vegetation availability (estimated from Copernicus Sentinel 2 satellite images) intensity usage locations. tested what factors influenced found that BGCs increased higher relative annual within group's home territory. Also, engaging BGC far away their were less likely win BGC. Regarding structure, smaller systematically won against larger groups, be explained by potentially rates individual free-riding occurring groups. This study sheds light on ecology encounter combination social critically impact dynamics non-human primate species. article part theme issue 'Intergroup conflict across taxa'.

Language: Английский

---

Variable intergroup encounters: what drives neutral and intolerant encounters in blue monkeys?

Animal Behaviour, Journal Year: 2024, Volume and Issue: 212, P. 1 - 12

Published: April 13, 2024

Language: Английский

---

Male services during between-group conflict: the ‘hired gun’ hypothesis revisited

Philosophical Transactions of the Royal Society B Biological Sciences, Journal Year: 2022, Volume and Issue: 377(1851)

Published: April 4, 2022

In many group-living mammals, philopatric females form the stable core of group and defend food or shelter against other groups females. Where males are larger, their participation could give female edge. How can secure contribution that neither father current infants, nor dominant male expecting to sire next generation infants? It has been proposed recruit these as ‘hired guns’, receiving social support copulations in exchange for fighting, interests male. We first develop logic this hypothesis unprecedented detail by considering potential pay-off consequences males. then provide empirical evidence existence hired guns context several primate species. The game-theoretical aspects phenomenon remain be studied, is distribution across contexts (e.g. predation avoidance) species gun phenomenon. This article part theme issue ‘Intergroup conflict taxa’.

Language: Английский

---

Factors Affecting the Outcome and Intensity of Intergroup Encounters in Crested Macaques (Macaca nigra)

International Journal of Primatology, Journal Year: 2023, Volume and Issue: 44(4), P. 696 - 721

Published: Aug. 1, 2023

Abstract Conspecific animal groups often compete for access to fitness-enhancing resources. The more valuable the resource at stake is, greater costs can afford outcompete their neighbours, leading between-group conflicts. We investigated what factors affected intergroup encounter outcome (win, loss, or draw) and intensity (level of aggression duration) in wild, crested macaques ( Macaca nigra ). collected data on 158 dyadic encounters among three Tangoko Nature Reserve (Indonesia) between November 2015 July 2016. Intergroup were likely have a clear winner larger group size difference was opposing when both rarely used location. Groups tended win specific parts home range, regardless numerical advantage, frequency use location its distance closest core area. Most involved aggression, but contact rare. None our candidate predictors helped explain differences escalation. Male common than female aggression. probability male participation increased with other sex. Males chased attacked females (i.e., herded them) most encounters. Our study suggests that intragroup sexual conflict occurs during macaques. More detailed longer studies may help understand behind macaque intensity.

Language: Английский

---

Do food distribution and competitor density affect agonistic behaviour within and between clans in a high fission–fusion species?

Royal Society Open Science, Journal Year: 2023, Volume and Issue: 10(12)

Published: Dec. 1, 2023

According to the ecological model of female social relationships (EMFSR), within-group competition and between-group in female-bonded species are shaped by food distribution. Strong contests expected over large, monopolizable resources high population density, but not when low-quality is distributed across undefended home ranges. Within-group be more frequent with increasing heterogeneity among feeding sites group size. We tested these predictions Asian elephants, which show traits associated infrequent contests-graminivory, fission-fusion overlapping examined how distribution competitor density affected agonistic interactions within between elephant clans (social groupings) Kabini grassland, southern India. found stronger between-clan contest grassland than that known from neighbouring forests, agonism females clans. Such strong was attributable being a food-rich habitat patch, thus supporting EMFSR. Within-clan also frequent, did increase heterogeneity, contradicting Contrary recent claims, within-clan size suggested constraints on large groups despite fission-fusion. High may explain such graminivory

Language: Английский

---

Stronger between-clan than within-clan contests and their ecological correlates in a non-territorial, fission-fusion species, the Asian elephant

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2019, Volume and Issue: unknown

Published: Sept. 1, 2019

Abstract Socioecological theory attributes variation in social organization of female-bonded species to differences within- and between-group competition, shaped by food distribution. Strong contests are expected over large, monopolisable resources, not generally that feed on low quality resources distributed across undefended home ranges. Within groups, frequent discrete feeding sites but low-quality, dispersed resources. We report the first tests socioecological theory, largely unexplored non-primate species, female Asian elephants. elephants show graminivory, overlapping ranges, high fission-fusion dynamics, traits thought be associated with infrequent contests. studied agonistic interactions within between elephant clans respect distribution, abundance, competitor density effects group size clan density, a grassland habitat around Kabini backwaters, southern India. found had three times grass biomass as adjacent forests, between-clan encounters were considerably higher than known from neighbouring forest. Individual-level agonism was also more clans. Thus, food-rich patch probably enabled strong contest competition under graminivory. Moreover, rate increased when present, duration positively related at contested sites. Despite within-clan somewhat frequent, influenced contradiction classic predictions, possibly because intensified due density. Interestingly, until intermediate sizes, suggesting tension within-group might govern size, since larger groups advantageous this regime. Our findings refine current understanding socioecology. predominant graminivory can especially large face ecological constraints Further, may arise despite non-territoriality becomes patchy is high. These changes effected anthropogenic alteration habitats.

Language: Английский

---