Outgroup conflict is widely discussed as a powerful selection pressure in social evolution, but studies quantifying fitness consequences have been somewhat limited in scope. In social species across a broad range of taxa (Figure 1), conspecific outsiders (see Glossary) threaten the valuable resources (e.g. territories, food, mates, and breeding positions) of groups and their members (Christensen and Radford, 2018; Beehner and Kitchen, 2007; Radford et al., 2016). Threats may come from single outsiders, same-sex coalitions, or rival groups; when groups compete, all or just a subset of individuals may participate. We use ‘outgroup’ conflict to encompass all scenarios involving a threat from conspecific outsiders, with ‘intergroup’ conflict the subset of those involving conflict between rival groups. Theoretical work indicates the selective importance of outgroup conflict in the evolution of within-group dynamics, cooperation, territoriality, and social structure (Alexander and Bargia, 1978; Choi and Bowles, 2007; Gaston, 1978; Rusch, 2014). By contrast, the traditional focus of empirical research has been on behaviour during contests between rivals (e.g. how different group members contribute, the costs and benefits of participation, what factors affect the level of escalation and who wins; Arseneau-Robar et al., 2016; Batchelor and Briffa, 2011; Beehner and Kitchen, 2007; Radford, 2003) and, more recently, broader behavioural changes arising as an immediate consequence of outgroup interactions (e.g. changes in individual vigilance and foraging decisions, within-group affiliation, and group movement patterns; Birch et al., 2019; Braga Goncalves and Radford, 2019; Crofoot, 2013; Morris-Drake et al., 2019; Preston et al., 2021; Radford, 2008). Fitness assessments are crucial in general to elucidate selection pressures; in the case of outgroup conflict, they would also help to bridge the gap between theoretical work considering lasting evolutionary differences between species and empirical work considering plastic and ephemeral behavioural responses within species. However, studies that explicitly quantify fitness consequences in the context of outgroup conflict have, to date, focused mostly on those arising immediately from physical contests (for exceptions, see Kerhoas et al., 2014; Lemoine et al., 2020; Rudolph and McEntee, 2016; Thompson et al., 2017).

Figure 1

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Beyond the immediate negative impacts of physical contests, broader attention needs to be paid to delayed, cumulative, and third-party fitness consequences, both negative and positive, that arise from living in a landscape of outgroup threat. Adversarial interactions with outsiders, especially if they escalate to physical violence, can lead to immediate direct costs to survival or reproductive success (e.g. loss of life or breeding position; Batchelor and Briffa, 2011; Thompson et al., 2017; Wrangham et al., 2006). However, we argue that consideration of fitness consequences should expand more systematically in three non-exclusive ways. First, as with predation (Creel and Christianson, 2008), the influence of outsiders is likely not restricted to confrontations between animals. For instance, there can be behavioural and hormonal effects of encountering secondary cues (e.g. faecal deposits) of rival presence (Christensen et al., 2016; Morris-Drake et al., 2019) and as a result of the overall risk of outgroup conflict (e.g. the number of territorial neighbours or the likelihood of intrusions; Lemoine et al., 2020; Radford, 2010; Samuni et al., 2020; Schoof and Jack, 2013), which could translate into fitness consequences. Second, in addition to the immediate effects of individual contests, there could be knock-on consequences from contest-related occurrences such as injuries and takeovers (Packer and Pusey, 1983; Schneider-Crease et al., 2020), from changes in behaviour or space use (Crofoot, 2013; Mares et al., 2012) and from the cumulative effects of multiple events (Isbell et al., 1990; Mosser and Packer, 2009). These could affect the fitness of both those directly involved and third-party individuals in the current and subsequent generations (Brunton, 2013; Goldstein et al., 1998; Noguera et al., 2017). Third, a particular event or scenario can have different consequences (including some that are positive) for different individuals within a group. For example, the takeover of a breeding position is most costly to the usurped individual but is positive for the incomer and may affect third-party opposite-sex (e.g. through improved reproductive opportunities) and same-sex (e.g. due to eviction) group members (Balshine et al., 1998; Clutton-Brock et al., 2001).

Here, we describe many of the myriad ways that outgroup conflict could have fitness consequences and what we believe is needed to increase our understanding of this relatively neglected aspect of sociality. There is increasing recognition that not all interactions with conspecific outsiders necessarily entail conflict (Furuichi, 2020; Pisor and Surbeck, 2019): in some species, such as bonobos (Pan paniscus), many intergroup encounters are described as peaceful (Fruth and Hohmann, 2018; but see Cheng et al., 2021); whilst in other species, some intergroup interactions at least are characterised by tolerance and/or are about just information exchange (Hashimoto et al., 2020; Radford and du Plessis, 2004). However, we know far less about these types of encounters and their consequences (Van Belle et al., 2020), and there may be elements of conflict even in seemingly tolerant or peaceful exchanges. Thus, our primary focus is a conflict perspective.

Our review has two main parts. In the first part, we describe the full range of potential fitness consequences that could arise from outgroup conflict. We begin by documenting the potential survival and reproductive consequences of single contests, which is the most-commonly considered scenario. Then, we step beyond contests to describe fitness consequences that can also result from interactions with cues of rival presence and the general landscape of outgroup threat, and beyond single interactions to describe cumulative effects of territorial pressure and elevated outgroup-induced stress. We discuss which individuals are affected negatively and positively, using illustrative examples from a range of taxa; we do not present a comprehensive review of the literature. To complement the text presentation of the core ideas, we split the concepts into examples of fitness consequences that arise directly to individuals (immediately, with a delay and cumulatively; Table 1) and those that arise to third-party group members (of the same or subsequent generations; Table 2). In the second part of the review, we provide suggestions about how to move the research field forward. First, we highlight the importance of considering how different types of outgroup conflict can generate different selection pressures and of investigating variation in fitness consequences within and between species. Then, we discuss the value of both theoretical modelling and empirical work, including long-term studies of natural populations, experimental manipulations, and interspecific meta-analyses.

Consequences of single contests

Outgroup contests can have immediate fitness consequences for those involved (Table 1a): there can be loss of life, extra-group mating, transfer of females, and replacement of breeders. The most extreme example is targeted killing: in chimpanzees (Pan troglodytes), for instance, coalitions of group members undertake coordinated incursions into neighbouring territories seemingly with the intention of attacking rivals (Goodall et al., 1979; Wilson et al., 2014), whilst raids to kill offspring in rival groups occur in species such as banded mongooses (Mungos mungo) and greater anis (Crotophaga major) (Cant et al., 2016; Strong et al., 2018). More commonly, the death of participating adults or juveniles accidentally caught in the melee arises as a by-product of escalated physical contests (Dyble et al., 2019; Thorne et al., 2003; Zahavi, 1990). There is also the possibility that engagement in fighting behaviour incurs an increased predation risk as participants are distracted (Hess et al., 2016; Jakobsson et al., 1995). Contest-related extra-group mating, which have negative reproductive consequences for the cuckolded male but are positive for the outsider and for the female if she gains better genes or access to an unrelated partner, can arise in two main ways. In some species, such as alpine marmots (Marmota marmota) and meerkats (Suricata suricatta), males ‘rove’ between groups specifically seeking mating opportunities (Lardy et al., 2015; Young et al., 2007); in other species, such as banded mongooses and common marmosets (Callithrix jacchus), individuals from different groups sneak matings whilst others are occupied in outgroup contests (Johnstone et al., 2020; Lazaro-Perea, 2001). Longer-lasting reproductive consequences result from the transfer of females between groups, as seen in various primate species (Breuer et al., 2016; Pines and Swedell, 2011), and enforced takeovers of breeding positions by outsiders (Figure 2), which occur across many taxa (primates: Beehner and Bergman, 2008; carnivores: Packer and Pusey, 1983; ungulates: Rubenstein and Nuñez, 2009; rodents: Hackländer and Arnold, 1999; birds: Ridley, 2011). A takeover follows a particular contest event, though that can sometimes be the culmination of a series of skirmishes over an extended period (Dunbar, 1987; Sicotte et al., 2017), with the usurped individuals losing future (and potentially current; see below) reproductive success unless they themselves can take over another group in turn.

Figure 2

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Outgroup contests can also generate a variety of knock-on fitness consequences. First, there can be delayed consequences for contest participants specifically (Table 1b). For instance, physical confrontations with outsiders can lead to injuries in a wide range of species (e.g. primates: Aureli et al., 2006; Rosenbaum et al., 2016; carnivores: Jordan et al., 2017; Mosser and Packer, 2009; mongooses: Dyble et al., 2019; Thompson et al., 2017; birds: Hannon et al., 1985; insects: Batchelor and Briffa, 2011; Rudolph and McEntee, 2016). Injured animals likely have a greater mortality rate and reduced reproductive performance (Bernardo and Agosta, 2005; Krause et al., 2017; Wilson, 1992). The second category of knock-on fitness consequences are those resulting in third-party individuals; that is, adult group members (Table 2a) and offspring (Table 2b) who were not necessarily directly involved in the original outgroup contest. For instance, in primate species where females may be kidnapped or voluntarily move to a rival group during contests, their own-group males may aggressively herd or coerce them to remain (Breuer et al., 2016). Another possibility is that lethal fights (see above) create a breeding vacancy that a subordinate group member benefits from filling (Johns et al., 2009). In at least one case, current non-breeders increase the likelihood of this occurrence: dry wood termite (Cryptotermes secundus) workers are believed to tunnel through to the next colony to incite an intergroup conflict, increasing the prospect of their king and queen being killed and a breeding vacancy arising (Korb and Roux, 2012).

Other striking examples of third-party consequences follow a change in breeder (Figure 2). This event may be beneficial to members of the opposite sex if there is now an unrelated dominant individual with whom they can mate. For example, in geladas (Theropithecus gelada), subordinate females are more likely to mature sexually in the two months following a male breeder takeover than in the preceding two months (Beehner and Lu, 2013), although accelerated sexual maturity may not always be beneficial. There are also potential negative consequences for existing group members. For instance, the remaining breeder may suffer a decrease in reproductive output; newly established pairings may produce fewer offspring compared to those who have been together a long time, as seen in alpine marmots, Azara’s owl monkeys (Aotus azarai), and pied babblers (Turdoides bicolor) (Fernandez-Duque and Huck, 2013; Lardy et al., 2015; Wiley and Ridley, 2018). The loss of a valuable ally could, in principle, result in a lower position in the dominance hierarchy and thus fewer mating opportunities or lowered survival (Cheney and Seyfarth, 1987). In a range of species, including African lions (Panthera leo), ursine colobus (Colobus vellerosus), and geladas, incoming male breeders kill dependent offspring sired by their predecessors to bring females into oestrus sooner (Packer and Pusey, 1983; Schneider-Crease et al., 2020; Sicotte et al., 2017); females may also exhibit higher abortion rates (Roberts et al., 2012; Zipple et al., 2017) and reduced fertility (Packer and Pusey, 1983) following male takeovers. Infanticide and feticide are costly for the reproductive success of the parents but benefit the new breeding males. Incoming breeders of both sexes sometimes evict existing group members: former breeders and other adults may be evicted as potential rivals, as seen in the cichlid Neolamprologus pulcher and Florida scrub-jays (Aphelocoma coerulescens) (Balshine et al., 1998; Goldstein et al., 1998), whilst independent offspring may be driven to disperse early (Elliot et al., 2014). In principle, some existing group members may also choose to disperse if the presence of a new breeder reduces inclusive fitness benefits (Eikenaar et al., 2007; Rowley and Russell, 1990; Spong et al., 2008). Individuals that leave or are evicted can suffer fitness consequences because being alone or in a small splinter group likely results in increased predation, reduced foraging success, and fatal encounters with rival groups (Cant et al., 2001; Kingma et al., 2016; Ridley et al., 2008); there is clear evidence that spending time alone has a negative effect on longevity in lions and meerkats (Cram et al., 2018; Elliot et al., 2014).

Outgroup contests can also have knock-on fitness consequences for all group members, rather than just specific individuals, because of group-size changes (Table 2). Contest-related deaths of adults and offspring, infanticide by incoming breeding males, female transfers, and dispersal or eviction following a change in breeder (details above) can all lead to a reduction in group size. Conversely, group-size increases can arise when a breeding individual is usurped by a same-sex coalition (Bygott et al., 1979; Ridley, 2011), when there is kidnapping of young from rival groups as seen in white-winged choughs (Corcorax melanorhamphos), banded mongooses and pied babblers (Heinsohn, 1991; Müller and Bell, 2009; Ridley et al., 2022), and when intraspecific slave-raiding occurs in insects such as the honey ant Myrmecocystus mimicus and the fire ant Solenopsis invicta (Bartz and Hlldobler, 1982; Tschinkel and Howard, 1983). Changes in group size can have a variety of fitness consequences, with the positive effects of increased group size the reverse of the negative ones arising from a reduced group size that we describe here. Individuals in smaller groups may suffer a general increase in mortality risk both from predation and starvation, although smaller groups might be less easily detected by predators and may have less competition among group members for limited resources (Krause and Ruxton, 2002). Fewer group members can also mean a reduced fighting strength when competing with conspecific rivals; relative group size is known to play an important role in intergroup contest outcomes, as evidenced from meerkats and green woodhoopoes (Phoeniculus purpureus) (Dyble et al., 2019; Radford and du Plessis, 2004). Moreover, loss of offspring can reduce the motivation to fight (Dyble et al., 2019). In cooperatively breeding species, the loss of helpers likely has negative effects on the inclusive fitness of breeders and other group members because helper number is often positively related to reproductive success (Brown et al., 1982; Russell et al., 2007; Taborsky et al., 2007). The loss of adults or offspring is especially costly for small groups that are more sensitive to a reduction in group size; in cooperatively breeding species, the maintenance of a critical size is vital to avoid group extinction (Courchamp et al., 1999; Taborsky et al., 2005).

Beyond contests

Some fitness consequences of outgroup conflict may arise not only from engagement in contests but also from interactions with secondary cues of rivals (Figure 3; Table 1b). Close encounters with outsiders and inspection of rival faeces, urine, and other secretions, for instance, could lead to disease and parasite transmission (Brown and Brown, 2004; Craft et al., 2011; Drewe, 2010; Nolan and Delaplane, 2016). As a specific example, modelling of disease transmission in African lions demonstrates the importance of contact between neighbouring prides (Craft et al., 2011). Susceptibility may be further increased in the context of outgroup conflict because social stress is a key factor in the pathogenesis of disease (Padgett et al., 1998; Quan et al., 2001). There are clear survival costs for animals who have contracted a disease or carry a high parasite load: these individuals may be more prone to, for example, lethal infections, starvation, and predation (Milinski, 1985; Robar et al., 2010). Individuals compromised in these ways may also have a lowered reproductive output (Fitze et al., 2004; Scott, 1988).

Figure 3

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Interactions with rivals and cues of their presence (e.g. olfactory or auditory indicators) can result in a range of behavioural responses that could have fitness consequences (Figure 3; Table 1b). For instance, there can be alterations in space use: groups might avoid areas where contests typically occur (Markham et al., 2012; Mech and Harper, 2002; Seiler et al., 2017) or might spend more time in border zones to guard against potential intrusions, as seen in green woodhoopoes that are more likely to roost where an intergroup conflict occurred earlier in the day (Radford and Fawcett, 2014). In both cases, this might mean more time spent in areas with fewer food resources, more predators and/or less-preferred sleeping sites, and thus an increased risk of starvation or predation (Crofoot, 2013). In addition to changes in space use, outgroup interactions can cause other behavioural responses. For instance, defensive actions can include greater patrolling and scent-marking (Amsler, 2010; Christensen et al., 2016; Jordan et al., 2007), whilst there may be more general increases in vigilance and intragroup affiliation (Morris-Drake et al., 2019; Radford, 2008; Lemoine et al., 2020; Walker et al., 2016), altered speed of movement, and reduced time spent resting (Christensen et al., 2016; Crofoot, 2013; Mirville et al., 2020). In dwarf mongooses (Helogale parvula), for example, presentation of rival-group faeces compared to control faeces resulted in more scent-marking, vigilance, and grooming (Christensen et al., 2016; Morris-Drake et al., 2019). Losing groups of white-faced capuchins (Cebus capucinus) moved further and faster, stopped less frequently and were active until later in the evening than groups that won intergroup encounters (Crofoot, 2013). These behavioural changes have likely knock-on consequences in terms of greater energy expenditure and reduced time for foraging, and thus lower body mass, and lessened parental care (Crofoot, 2013; Mares et al., 2012; Morris-Drake et al., 2021), which could influence the reproductive success and survival chances of both adults and dependent young (Table 2).

Many of the studies considering behavioural effects of outgroup conflict have focused on the period immediately following a single interaction (up to 1 or 2 hr in the aftermath), when responses are most likely due to elevated stress (Culbert et al., 2021; Samuni et al., 2020; Schoof and Jack, 2013) or exclusion from territorial areas (Crofoot, 2013; Mirville et al., 2020). Fitness consequences from such short-term, single occurrences might be relatively small, in at least some instances. However, there is also some evidence for longer-lasting behavioural effects of single events (Dyble et al., 2019; Radford and Fawcett, 2014) and that the overall threat of outgroup conflict (a ‘landscape of fear’) may cause avoidance of likely conflict areas (Markham et al., 2012; Seiler et al., 2017) and behavioural changes when in such locations (Radford, 2010). Moreover, there could be a cumulative build-up from multiple outgroup events which results in behavioural changes not just in the immediate aftermath of each interaction, but also more generally to baseline activity (Morris-Drake et al., 2021; Thompson et al., 2020). As these scenarios all increase the frequency and magnitude of behavioural changes, they enhance the likelihood of fitness consequences arising from them.

Beyond single interactions

In addition to cumulative behavioural effects (see above), a build-up of outsider pressure over time can lead to changes in territory ownership or size. In extreme cases, a group might be usurped from its whole territory either by neighbours or groups from further afield (Isbell et al., 1990; Ligon and Ligon, 1990; Mitani et al., 2010). For instance, Goodall, 1986 famously documented how the Kasekela community of chimpanzees at Gombe National Park took over the territory of the neighbouring Kahama community after a series of lethal attacks. More commonly, a group may lose part of its territory to a stronger neighbour, as seen in rattling cisticolas (Cisticola chiniana), vervet monkeys (Chlorocebus pygerythrus), chowchillas (Orthonyx spaldingii), and lions (Carlson, 1986; Isbell et al., 1990; Jansen, 1999; Mosser and Packer, 2009). Losing groups then have access to areas of reduced quality and/or less familiarity, and thus individuals have potentially lessened survival chances and reproductive success (Table 1c). Survival might be reduced due to reliance on poorer quality food resources, more time where there is a higher predation risk (in terms of predator numbers and less familiarity with escape options) or limited availability of safe sleeping sites (Crofoot, 2013; Isbell et al., 1990; Markham et al., 2012; Mosser and Packer, 2009). Reduced access to valuable resources could also have negative impacts on both current and future reproductive success, as documented for mud crabs (Panopeus herbstii), Seychelles warblers (Acrocephalus sechellensis), and chimpanzees (Griffen and Norelli, 2015; Komdeur and Edelaar, 2001; Thompson et al., 2007). These consequences are qualitatively similar to at least some arising from temporary avoidance of areas (see ‘Beyond contests,’ above). However, when there is a permanent change in territory ownership, there are also benefits to those groups gaining additional resources, who likely experience positive effects on survival and reproductive success. One further benefit of increasing territory size in some bird species, such as Seychelles warblers and Florida scrub jays, is that sons can ‘bud’ off part of the territory and so begin reproducing independently (Komdeur and Edelaar, 2001; Stallcup and Woolfenden, 1978).

The cumulative build-up of outgroup threat likely generates chronic stress (Samuni et al., 2019), with survival and reproductive consequences for the affected individuals (Figure 4; Table 1c). Chronic stress is associated with reduced body condition and increased chances of mortality (Campos et al., 2021; Pride, 2005; Wey et al., 2014) due to, for example, increased susceptibility to predation (Romero et al., 2009; Vuarin et al., 2019). Chronic stress may also reduce reproductive investment and success: it can have negative effects on courtship activity (Romero-Diaz et al., 2019; Schreck, 2010), breeding rates (Dulude‐de Broin et al., 2020; Mileva et al., 2011), fecundity (O’Brien et al., 2018; Schreck, 2010), egg size and composition (Ensminger et al., 2018; Henriksen et al., 2013), and hatching and fledging success (Cyr and Michael Romero, 2007; Eriksen et al., 2015; Kleist et al., 2018). Many of these effects can occur in the same species (Zanette et al., 2011). There has been only a limited amount of research examining the reproductive consequences of outgroup conflict directly. A recent observational study on chimpanzees found that an increased cumulative pressure from intergroup conflict is correlated with longer inter-birth intervals and reduced offspring survival (Lemoine et al., 2020). Experimental work with cichlid fish has demonstrated that an increase in outgroup threat can drive longer inter-clutch intervals, cause females to produce relatively smaller eggs with less protein, and result in fewer offspring surviving to one month post-hatching (Braga Goncalves & Radford, In revision). The consequences are not necessarily always negative, however, as outgroup threat has been found to be correlated with reduced foetal mortality in crested macaques (Macaca nigra) and banded mongooses (Kerhoas et al., 2014; Thompson et al., 2017) and with increased pup survival in dwarf mongooses (Morris-Drake, 2021).

Figure 4

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As with individual contests (see ‘Consequences of single contests,’ above), there can be knock-on consequences of cumulative outgroup effects for third-party individuals – most notably, in this case, for offspring (Figure 4; Table 2b). These could arise through maternal effects, due to conflict-induced stress in mothers (Brunton, 2013; Culbert et al., 2021). In general, offspring from smaller eggs and those with, for example, higher levels of corticosterone might be smaller, be of lower quality, and have learning difficulties (Dantzer et al., 2019; McCormick, 1998; Roche et al., 2012). Stress, as well as engagement in conflict-related activities, could also decrease the quality of offspring care by parents and, in the case of cooperative breeders, non-breeding helpers (Mares et al., 2012; Stein and Bell, 2012). Carers might abandon nests, whilst offspring could be at greater risk of starvation if there is reduced provisioning and at greater risk of predation as a direct consequence of decreased protection or indirectly if smaller offspring are more vulnerable (Ahnesjo, 1992; Ridley, 2016; Vitousek et al., 2014; Vitousek et al., 2018). Moreover, early-life stress on offspring and lower growth has lasting effects: there is increasing evidence that developmental trajectories shape the physiology and behaviour of adults, with major effects on survival and reproductive success (Cram et al., 2017; English et al., 2013; Marshall et al., 2017; Noguera et al., 2017; Royle et al., 2005).

1. 1. Adams ES

   (1990) Boundary disputes in the territorial ant Azteca trigona: effects of asymmetries in colony size

   Animal Behaviour 39:321–328.

   https://doi.org/10.1016/S0003-3472(05)80877-2

   • PubMed
   • Google Scholar
2. 1. Ahnesjo I

   (1992) Consequences of male brood care; weight and number of newborn in a sex-role reversed pipefish

   Functional Ecology 6:274.

   https://doi.org/10.2307/2389517

   • Google Scholar
3. 1. Alexander RD
   2. Bargia G

   (1978) Group selection, altruism, and the levels of organization of life

   Annual Review of Ecology and Systematics 9:449–474.

   https://doi.org/10.1146/annurev.es.09.110178.002313

   • Google Scholar
4. 1. Amsler SJ

   (2010) Energetic costs of territorial boundary patrols by wild chimpanzees

   American Journal of Primatology 72:93–103.

   https://doi.org/10.1002/ajp.20757

   • PubMed
   • Google Scholar
5. 1. Arseneau-Robar TJM
   2. Taucher AL
   3. Müller E
   4. van Schaik C
   5. Bshary R
   6. Willems EP

   (2016) Female monkeys use both the carrot and the stick to promote male participation in intergroup fights

   Proceedings of the Royal Society B: Biological Sciences 283:20161817.

   https://doi.org/10.1098/rspb.2016.1817

   • PubMed
   • Google Scholar
6. 1. Ashton BJ
   2. Kennedy P
   3. Radford AN

   (2020) Interactions with conspecific outsiders as drivers of cognitive evolution

   Nature Communications 11:4937.

   https://doi.org/10.1038/s41467-020-18780-3

   • PubMed
   • Google Scholar
7. 1. Aureli F
   2. Schaffner CM
   3. Verpooten J
   4. Slater K
   5. Ramos-Fernandez G

   (2006) Raiding parties of male spider monkeys: Insights into human warfare?

   American Journal of Physical Anthropology 131:486–497.

   https://doi.org/10.1002/ajpa.20451

   • PubMed
   • Google Scholar
8. 1. Balshine S
   2. Neat FC
   3. Reid H
   4. Taborsky M

   (1998) Paying to stay or paying to breed? Field evidence for direct benefits of helping behavior in a cooperatively breeding fish

   Behavioral Ecology 9:432–438.

   https://doi.org/10.1093/beheco/9.5.432

   • Google Scholar
9. 1. Balshine S
   2. Leach B
   3. Neat F
   4. Reid H
   5. Taborsky M
   6. Werner N

   (2001) Correlates of group size in a cooperatively breeding cichlid fish (Neolamprologus pulcher)

   Behavioral Ecology and Sociobiology 50:134–140.

   https://doi.org/10.1007/s002650100343

   • Google Scholar
10. 1. Bartz SH
    2. Hlldobler B

    (1982) Colony founding in Myrmecocystus mimicus Wheeler (Hymenoptera: Formicidae) and the evolution of foundress associations

    Behavioral Ecology and Sociobiology 10:137–147.

    https://doi.org/10.1007/BF00300174

    • Google Scholar
11. 1. Batchelor TP
    2. Briffa M

    (2011) Fight tactics in wood ants: Individuals in smaller groups fight harder but die faster

    Proceedings of the Royal Society B: Biological Sciences 278:3243–3250.

    https://doi.org/10.1098/rspb.2011.0062

    • PubMed
    • Google Scholar
12. 1. Beehner J
    2. Kitchen D

    (2007) Factors affecting individual participation in group-level aggression among non-human primates

    Behaviour 144:1551–1581.

    https://doi.org/10.1163/156853907782512074

    • Google Scholar
13. 1. Beehner JC
    2. Bergman TJ

    (2008) Infant mortality following male takeovers in wild geladas

    American Journal of Primatology 70:1152–1159.

    https://doi.org/10.1002/ajp.20614

    • PubMed
    • Google Scholar
14. 1. Beehner JC
    2. Lu A

    (2013) Reproductive suppression in female primates: A review

    Evolutionary Anthropology 22:226–238.

    https://doi.org/10.1002/evan.21369

    • PubMed
    • Google Scholar
15. 1. Bernardo J
    2. Agosta SJ

    (2005) Evolutionary implications of hierarchical impacts of nonlethal injury on reproduction, including maternal effects

    Biological Journal of the Linnean Society 86:309–331.

    https://doi.org/10.1111/j.1095-8312.2005.00532.x

    • Google Scholar
16. 1. Birch G
    2. Cant MA
    3. Thompson FJ

    (2019) Behavioural response of workers to repeated intergroup encounters in the harvester ant Messor barbarus

    Insectes Sociaux 66:491–500.

    https://doi.org/10.1007/s00040-019-00710-2

    • Google Scholar
17. 1. Braga Goncalves I
    2. Radford AN

    (2019) Experimental evidence that intruder and group member attributes affect outgroup defence and associated within-group interactions in a social fish

    Proceedings of the Royal Society B: Biological Sciences 286:20191261.

    https://doi.org/10.1098/rspb.2019.1261

    • PubMed
    • Google Scholar
18. Preprint

    1. Braga Goncalves I
    2. Radford AN

    (2022) Experimental evidence that chronic outgroup conflict reduces reproductive success in a cooperatively breeding fish

    bioRxiv.

    https://doi.org/10.1101/2021.08.11.455992

    • Google Scholar
19. 1. Breuer T
    2. Robbins AM
    3. Robbins MM

    (2016) Sexual coercion and courtship by male western gorillas

    Primates 57:29–38.

    https://doi.org/10.1007/s10329-015-0496-9

    • PubMed
    • Google Scholar
20. 1. Brown JL
    2. Brown ER
    3. Brown SD
    4. Dow DD

    (1982) Helpers: Effects of experimental removal on reproductive success

    Science 215:421–422.

    https://doi.org/10.1126/science.215.4531.421

    • PubMed
    • Google Scholar
21. 1. Brown CR
    2. Brown MB

    (2004) Empirical measurement of parasite transmission between groups in a colonial bird

    Ecology 85:1619–1626.

    https://doi.org/10.1890/03-0206

    • Google Scholar
22. 1. Brunton PJ

    (2013) Effects of maternal exposure to social stress during pregnancy: Consequences for mother and offspring

    Reproduction 146:R175–R189.

    https://doi.org/10.1530/REP-13-0258

    • PubMed
    • Google Scholar
23. 1. Bygott JD
    2. Bertram BCR
    3. Hanby JP

    (1979) Male lions in large coalitions gain reproductive advantages

    Nature 282:839–841.

    https://doi.org/10.1038/282839a0

    • Google Scholar
24. 1. Campos FA
    2. Archie EA
    3. Gesquiere LR
    4. Tung J
    5. Altmann J
    6. Alberts SC

    (2021) Glucocorticoid exposure predicts survival in female baboons

    Science Advances 7:eabf6759.

    https://doi.org/10.1126/sciadv.abf6759

    • PubMed
    • Google Scholar
25. 1. Cant MA
    2. Otali E
    3. Mwanguhya F

    (2001) Eviction and dispersal in co‐operatively breeding banded mongooses (Mungos mungo)

    Journal of Zoology 254:155–162.

    https://doi.org/10.1017/S0952836901000668

    • Google Scholar
26. Book

    1. Cant MA
    2. Nichols HJ
    3. Thompson FJ
    4. Vitikainen EIK

    (2016) Banded mongooses: Demography, life history, and social behavior

    In: Koenig WD, Dickinson JL, editors. Cooperative Breeding in Vertebrates: Studies of Ecology, Evolution and Behavior. Cambridge: Cambridge University Press. pp. 318–337.

    https://doi.org/10.1017/CBO9781107338357.019

    • Google Scholar
27. 1. Carlson A

    (1986) Group territoriality in the rattling cisticola, Cisticola chiniana

    Oikos 47:181.

    https://doi.org/10.2307/3566044

    • Google Scholar
28. 1. Cheney DL
    2. Seyfarth RM

    (1987) The influence of intergroup competition on the survival and reproduction of female vervet monkeys

    Behavioral Ecology and Sociobiology 21:375–386.

    https://doi.org/10.1007/BF00299932

    • Google Scholar
29. 1. Cheng L
    2. Lucchesi S
    3. Mundry R
    4. Samuni L
    5. Deschner T
    6. Surbeck M

    (2021) Variation in aggression rates and urinary cortisol levels indicates intergroup competition in wild bonobos

    Hormones and Behavior 128:104914.

    https://doi.org/10.1016/j.yhbeh.2020.104914

    • PubMed
    • Google Scholar
30. 1. Choi JK
    2. Bowles S

    (2007) The coevolution of parochial altruism and war

    Science 318:636–640.

    https://doi.org/10.1126/science.1144237

    • PubMed
    • Google Scholar
31. 1. Christensen C
    2. Kern JM
    3. Bennitt E
    4. Radford AN

    (2016) Rival group scent induces changes in dwarf mongoose immediate behavior and subsequent movement

    Behavioral Ecology 27:1627–1634.

    https://doi.org/10.1093/beheco/arw092

    • Google Scholar
32. 1. Christensen C
    2. Radford AN

    (2018) Dear enemies or nasty neighbors? Causes and consequences of variation in the responses of group-living species to territorial intrusions

    Behavioral Ecology 29:1004–1013.

    https://doi.org/10.1093/beheco/ary010

    • Google Scholar
33. 1. Clutton-Brock TH
    2. Brotherton PN
    3. Russell AF
    4. O’Riain MJ
    5. Gaynor D
    6. Kansky R
    7. Griffin A
    8. Manser M
    9. Sharpe L
    10. McIlrath GM
    11. Small T
    12. Moss A
    13. Monfort S

    (2001) Cooperation, control, and concession in meerkat groups

    Science 291:478–481.

    https://doi.org/10.1126/science.291.5503.478

    • PubMed
    • Google Scholar
34. 1. Clutton-Brock T
    2. Sheldon BC

    (2010) Individuals and populations: the role of long-term, individual-based studies of animals in ecology and evolutionary biology

    Trends in Ecology & Evolution 25:562–573.

    https://doi.org/10.1016/j.tree.2010.08.002

    • PubMed
    • Google Scholar
35. 1. Courchamp F
    2. Grenfell B
    3. Clutton-Brock T

    (1999) Population dynamics of obligate cooperators

    Proceedings of the Royal Society B: Biological Sciences 266:557–563.

    https://doi.org/10.1098/rspb.1999.0672

    • Google Scholar
36. 1. Craft ME
    2. Volz E
    3. Packer C
    4. Meyers LA

    (2011) Disease transmission in territorial populations: the small-world network of Serengeti lions

    Journal of the Royal Society, Interface 8:776–786.

    https://doi.org/10.1098/rsif.2010.0511

    • PubMed
    • Google Scholar
37. 1. Cram DL
    2. Monaghan P
    3. Gillespie R
    4. Clutton-Brock T

    (2017) Effects of early-life competition and maternal nutrition on telomere lengths in wild meerkats

    Proceedings of the Royal Society B: Biological Sciences 284:20171383.

    https://doi.org/10.1098/rspb.2017.1383

    • PubMed
    • Google Scholar
38. 1. Cram DL
    2. Monaghan P
    3. Gillespie R
    4. Dantzer B
    5. Duncan C
    6. Spence-Jones H
    7. Clutton-Brock T

    (2018) Rank-related contrasts in longevity arise from extra-group excursions not delayed senescence in a cooperative mammal

    Current Biology 28:2934–2939.

    https://doi.org/10.1016/j.cub.2018.07.021

    • PubMed
    • Google Scholar
39. 1. Creel S
    2. Christianson D

    (2008) Relationships between direct predation and risk effects

    Trends in Ecology & Evolution 23:194–201.

    https://doi.org/10.1016/j.tree.2007.12.004

    • PubMed
    • Google Scholar
40. 1. Crofoot MC
    2. Gilby IC
    3. Wikelski MC
    4. Kays RW

    (2008) Interaction location outweighs the competitive advantage of numerical superiority in Cebus capucinus intergroup contests

    PNAS 105:577–581.

    https://doi.org/10.1073/pnas.0707749105

    • PubMed
    • Google Scholar
41. 1. Crofoot MC

    (2013) The cost of defeat: Capuchin groups travel further, faster and later after losing conflicts with neighbors

    American Journal of Physical Anthropology 152:79–85.

    https://doi.org/10.1002/ajpa.22330

    • PubMed
    • Google Scholar
42. 1. Culbert BM
    2. Ligocki IY
    3. Salena MG
    4. Wong MYL
    5. Hamilton IM
    6. Aubin-Horth N
    7. Bernier NJ
    8. Balshine S

    (2021) Rank- and sex-specific differences in the neuroendocrine regulation of glucocorticoids in a wild group-living fish

    Hormones and Behavior 136:105079.

    https://doi.org/10.1016/j.yhbeh.2021.105079

    • PubMed
    • Google Scholar
43. 1. Cyr NE
    2. Michael Romero L

    (2007) Chronic stress in free-living European starlings reduces corticosterone concentrations and reproductive success

    General and Comparative Endocrinology 151:82–89.

    https://doi.org/10.1016/j.ygcen.2006.12.003

    • PubMed
    • Google Scholar
44. 1. Dantzer B
    2. Dubuc C
    3. Goncalves IB
    4. Cram DL
    5. Bennett NC
    6. Ganswindt A
    7. Heistermann M
    8. Duncan C
    9. Gaynor D
    10. Clutton-Brock TH

    (2019) The development of individual differences in cooperative behaviour: maternal glucocorticoid hormones alter helping behaviour of offspring in wild meerkats

    Philosophical Transactions of the Royal Society B: Biological Sciences 374:20180117.

    https://doi.org/10.1098/rstb.2018.0117

    • PubMed
    • Google Scholar
45. 1. Drewe JA

    (2010) Who infects whom? Social networks and tuberculosis transmission in wild meerkats

    Proceedings of the Royal Society B: Biological Sciences 277:633–642.

    https://doi.org/10.1098/rspb.2009.1775

    • PubMed
    • Google Scholar
46. 1. Dulude‐de Broin F
    2. Hamel S
    3. Mastromonaco GF
    4. Côté SD
    5. Lemaître J

    (2020) Predation risk and mountain goat reproduction: Evidence for stress‐induced breeding suppression in a wild ungulate

    Functional Ecology 34:1003–1014.

    https://doi.org/10.1111/1365-2435.13514

    • Google Scholar
47. 1. Dunbar RIM

    (1987) Habitat quality, population dynamics, and group composition in colobus monkeys (Colobus guereza)

    International Journal of Primatology 8:299–329.

    https://doi.org/10.1007/BF02737386

    • Google Scholar
48. 1. Dyble M
    2. Houslay TM
    3. Manser MB
    4. Clutton-Brock T

    (2019) Intergroup aggression in meerkats

    Proceedings of the Royal Society B: Biological Sciences 286:20191993.

    https://doi.org/10.1098/rspb.2019.1993

    • PubMed
    • Google Scholar
49. 1. Eikenaar C
    2. Richardson DS
    3. Brouwer L
    4. Komdeur J

    (2007) Parent presence, delayed dispersal, and territory acquisition in the Seychelles warbler

    Behavioral Ecology 18:874–879.

    https://doi.org/10.1093/beheco/arm047

    • Google Scholar
50. 1. Elliot NB
    2. Valeix M
    3. Macdonald DW
    4. Loveridge AJ

    (2014) Social relationships affect dispersal timing revealing a delayed infanticide in African lions

    Oikos 123:1049–1056.

    https://doi.org/10.1111/oik.01266

    • Google Scholar
51. 1. English S
    2. Huchard E
    3. Nielsen JF
    4. Clutton-Brock TH

    (2013) Early growth, dominance acquisition and lifetime reproductive success in male and female cooperative meerkats

    Ecology and Evolution 3:4401–4407.

    https://doi.org/10.1002/ece3.820

    • PubMed
    • Google Scholar
52. 1. Ensminger DC
    2. Langkilde T
    3. Owen DAS
    4. MacLeod KJ
    5. Sheriff MJ

    (2018) Maternal stress alters the phenotype of the mother, her eggs and her offspring in a wild-caught lizard

    The Journal of Animal Ecology 87:1685–1697.

    https://doi.org/10.1111/1365-2656.12891

    • PubMed
    • Google Scholar
53. 1. Eriksen MS
    2. Poppe TT
    3. McCormick M
    4. Damsgård B
    5. Salte R
    6. Braastad BO
    7. Bakken M

    (2015) Simulated maternal pre-spawning stress affects offspring’s attributes in farmed Atlantic salmon Salmo salar (Linnaeus, 1758)

    Aquaculture Research 46:1480–1489.

    https://doi.org/10.1111/are.12301

    • Google Scholar
54. 1. Fernandez-Duque E
    2. Huck M

    (2013) Till death (or an intruder) do us part: Intrasexual-competition in a monogamous primate

    PLOS ONE 8:e53724.

    https://doi.org/10.1371/journal.pone.0053724

    • PubMed
    • Google Scholar
55. 1. Fitze PS
    2. Tschirren B
    3. Richner H

    (2004) Life history and fitness consequences of ectoparasites

    Journal of Animal Ecology 73:216–226.

    https://doi.org/10.1111/j.0021-8790.2004.00799.x

    • Google Scholar
56. 1. Franks NR
    2. Partridge LW

    (1993) Lanchester battles and the evolution of combat in ants

    Animal Behaviour 45:197–199.

    https://doi.org/10.1006/anbe.1993.1021

    • Google Scholar
57. 1. Fruth B
    2. Hohmann G

    (2018) Food sharing across borders

    Human Nature 29:91–103.

    https://doi.org/10.1007/s12110-018-9311-9

    • Google Scholar
58. 1. Furrer RD
    2. Kyabulima S
    3. Willems EP
    4. Cant MA
    5. Manser MB

    (2011) Location and group size influence decisions in simulated intergroup encounters in banded mongooses

    Behavioral Ecology 22:493–500.

    https://doi.org/10.1093/beheco/arr010

    • Google Scholar
59. 1. Furuichi T

    (2020) Variation in intergroup relationships among species and among and within local populations of African apes

    International Journal of Primatology 41:203–223.

    https://doi.org/10.1007/s10764-020-00134-x

    • Google Scholar
60. 1. Gaston AJ

    (1978) The evolution of group territorial behavior and cooperative breeding

    The American Naturalist 112:1091–1100.

    https://doi.org/10.1086/283348

    • Google Scholar
61. 1. Gavrilets S
    2. Fortunato L

    (2014) A solution to the collective action problem in between-group conflict with within-group inequality

    Nature Communications 5:3526.

    https://doi.org/10.1038/ncomms4526

    • PubMed
    • Google Scholar
62. 1. Goldstein JM
    2. Woolfenden GE
    3. Hailman JP

    (1998) A same-sex stepparent shortens a prebreeder’s duration on the natal territory: Tests of two hypotheses in Florida scrub-jays

    Behavioral Ecology and Sociobiology 44:15–22.

    https://doi.org/10.1007/s002650050510

    • Google Scholar
63. Book

    1. Goodall J
    2. Bandura A
    3. Bergmann E
    4. Busse C
    5. Matam H
    6. Mpongo E
    7. Pierce A
    8. Riss D

    (1979)

    Inter-community interactions in the chimpanzee populations of the Gombe National Park

    In: Hambrug D, McCown E, editors. The Great Apes. Benjamin/Cummings. pp. 13–53.

    • Google Scholar
64. Book

    1. Goodall J

    (1986)

    The Chimpanzees of Gombe: Patterns of Behavior

    Belknap Press.

    • Google Scholar
65. 1. Griffen BD
    2. Norelli AP

    (2015) Spatially variable habitat quality contributes to within-population variation in reproductive success

    Ecology and Evolution 5:1474–1483.

    https://doi.org/10.1002/ece3.1427

    • PubMed
    • Google Scholar
66. 1. Hackländer K
    2. Arnold W

    (1999) Male-caused failure of female reproduction and its adaptive value in alpine marmots (Marmota marmota)

    Behavioral Ecology 10:592–597.

    https://doi.org/10.1093/beheco/10.5.592

    • Google Scholar
67. 1. Hannon SJ
    2. Mumme RL
    3. Koenig WD
    4. Pitelka FA

    (1985) Replacement of breeders and within-group conflict in the cooperatively breeding acorn woodpecker

    Behavioral Ecology and Sociobiology 17:303–312.

    https://doi.org/10.1007/BF00293208

    • Google Scholar
68. 1. Hashimoto C
    2. Isaji M
    3. Mouri K
    4. Takemoto H

    (2020) Intergroup encounters of chimpanzees (Pan troglodytes) from the female perspective

    International Journal of Primatology 41:171–180.

    https://doi.org/10.1007/s10764-020-00145-8

    • Google Scholar
69. 1. Heinsohn RG

    (1991) Kidnapping and reciprocity in cooperatively breeding white-winged choughs

    Animal Behaviour 41:1097–1100.

    https://doi.org/10.1016/S0003-3472(05)80652-9

    • Google Scholar
70. 1. Henriksen R
    2. Rettenbacher S
    3. Groothuis TGG

    (2013) Maternal corticosterone elevation during egg formation in chickens (Gallus gallus domesticus) influences offspring traits, partly via prenatal undernutrition

    General and Comparative Endocrinology 191:83–91.

    https://doi.org/10.1016/j.ygcen.2013.05.028

    • PubMed
    • Google Scholar
71. 1. Henschel JR
    2. Skinner JD

    (1991) Territorial behaviour by a clan of spotted hyaenas Crocuta crocuta

    Ethology 88:223–235.

    https://doi.org/10.1111/j.1439-0310.1991.tb00277.x

    • Google Scholar
72. 1. Herbinger I
    2. Papworth S
    3. Boesch C
    4. Zuberbühler K

    (2009) Vocal, gestural and locomotor responses of wild chimpanzees to familiar and unfamiliar intruders: a playback study

    Animal Behaviour 78:1389–1396.

    https://doi.org/10.1016/j.anbehav.2009.09.010

    • Google Scholar
73. 1. Hess S
    2. Fischer S
    3. Taborsky B

    (2016) Territorial aggression reduces vigilance but increases aggression towards predators in a cooperatively breeding fish

    Animal Behaviour 113:229–235.

    https://doi.org/10.1016/j.anbehav.2016.01.008

    • Google Scholar
74. 1. Isbell LA
    2. Cheney DL
    3. Seyfarth RM

    (1990) Costs and benefits of home range shifts among vervet monkeys (Cercopithecus aethiops) in Amboseli National Park, Kenya

    Behavioral Ecology and Sociobiology 27:351–358.

    https://doi.org/10.1007/BF00164006

    • Google Scholar
75. 1. Jakobsson S
    2. Brick O
    3. Kullberg C

    (1995) Escalated fighting behaviour incurs increased predation risk

    Animal Behaviour 49:235–239.

    https://doi.org/10.1016/0003-3472(95)80172-3

    • Google Scholar
76. 1. Jansen A

    (1999) Home ranges and group-territoriality in chowchillas Orthonyx spaldingii

    Emu - Austral Ornithology 99:280–290.

    https://doi.org/10.1071/MU99033

    • Google Scholar
77. 1. Johns PM
    2. Howard KJ
    3. Breisch NL
    4. Rivera A
    5. Thorne BL

    (2009) Nonrelatives inherit colony resources in a primitive termite

    PNAS 106:17452–17456.

    https://doi.org/10.1073/pnas.0907961106

    • PubMed
    • Google Scholar
78. 1. Johnson DDP
    2. MacKay NJ

    (2015) Fight the power: Lanchester’s laws of combat in human evolution

    Evolution and Human Behavior 36:152–163.

    https://doi.org/10.1016/j.evolhumbehav.2014.11.001

    • Google Scholar
79. 1. Johnstone RA
    2. Cant MA
    3. Cram D
    4. Thompson FJ

    (2020) Exploitative leaders incite intergroup warfare in a social mammal

    PNAS 117:29759–29766.

    https://doi.org/10.1073/pnas.2003745117

    • PubMed
    • Google Scholar
80. 1. Jordan NR
    2. Cherry MI
    3. Manser MB

    (2007) Latrine distribution and patterns of use by wild meerkats: Implications for territory and mate defence

    Animal Behaviour 73:613–622.

    https://doi.org/10.1016/j.anbehav.2006.06.010

    • PubMed
    • Google Scholar
81. 1. Jordan NR
    2. Buse C
    3. Wilson AM
    4. Golabek KA
    5. Apps PJ
    6. Lowe JC
    7. Van der Weyde LK
    8. Weldon McNutt J

    (2017) Dynamics of direct inter-pack encounters in endangered African wild dogs

    Behavioral Ecology and Sociobiology 71:115.

    https://doi.org/10.1007/s00265-017-2338-9

    • Google Scholar
82. 1. Kaiser SA
    2. Sillett TS
    3. Risk BB
    4. Webster MS

    (2015) Experimental food supplementation reveals habitat-dependent male reproductive investment in a migratory bird

    Proceedings of the Royal Society B: Biological Sciences 282:20142523.

    https://doi.org/10.1098/rspb.2014.2523

    • PubMed
    • Google Scholar
83. 1. Kerhoas D
    2. Perwitasari-Farajallah D
    3. Agil M
    4. Widdig A
    5. Engelhardt A

    (2014) Social and ecological factors influencing offspring survival in wild macaques

    Behavioral Ecology 25:1164–1172.

    https://doi.org/10.1093/beheco/aru099

    • PubMed
    • Google Scholar
84. 1. Kingma SA
    2. Komdeur J
    3. Hammers M
    4. Richardson DS

    (2016) The cost of prospecting for dispersal opportunities in a social bird

    Biology Letters 12:20160316.

    https://doi.org/10.1098/rsbl.2016.0316

    • PubMed
    • Google Scholar
85. 1. Kleist NJ
    2. Guralnick RP
    3. Cruz A
    4. Lowry CA
    5. Francis CD

    (2018) Chronic anthropogenic noise disrupts glucocorticoid signaling and has multiple effects on fitness in an avian community

    PNAS 115:E648–E657.

    https://doi.org/10.1073/pnas.1709200115

    • PubMed
    • Google Scholar
86. 1. Komdeur J
    2. Edelaar P

    (2001) Male Seychelles warblers use territory budding to maximize lifetime fitness in a saturated environment

    Behavioral Ecology 12:706–715.

    https://doi.org/10.1093/beheco/12.6.706

    • Google Scholar
87. 1. Konrad KA
    2. Morath F

    (2015) Evolutionary determinants of war

    Defence and Peace Economics 27:520–534.

    https://doi.org/10.1080/10242694.2014.995890

    • Google Scholar
88. 1. Korb J
    2. Roux EA

    (2012) Why join a neighbour: Fitness consequences of colony fusions in termites

    Journal of Evolutionary Biology 25:2161–2170.

    https://doi.org/10.1111/j.1420-9101.2012.02617.x

    • PubMed
    • Google Scholar
89. Book

    1. Krause J
    2. Ruxton G

    (2002)

    Living in Groups

    Oxford: Oxford University Press.

    • Google Scholar
90. 1. Krause J
    2. Herbert-Read JE
    3. Seebacher F
    4. Domenici P
    5. Wilson ADM
    6. Marras S
    7. Svendsen MBS
    8. Strömbom D
    9. Steffensen JF
    10. Krause S
    11. Viblanc PE
    12. Couillaud P
    13. Bach P
    14. Sabarros PS
    15. Zaslansky P
    16. Kurvers R

    (2017) Injury-mediated decrease in locomotor performance increases predation risk in schooling fish

    Philosophical Transactions of the Royal Society B: Biological Sciences 372:20160232.

    https://doi.org/10.1098/rstb.2016.0232

    • PubMed
    • Google Scholar
91. 1. Lardy S
    2. Allainé D
    3. Bonenfant C
    4. Cohas A

    (2015) Sex-specific determinants of fitness in a social mammal

    Ecology 96:2947–2959.

    https://doi.org/10.1890/15-0425.1

    • PubMed
    • Google Scholar
92. 1. Lazaro-Perea C

    (2001) Intergroup interactions in wild common marmosets, Callithrix jacchus: Territorial defence and assessment of neighbours

    Animal Behaviour 62:11–21.

    https://doi.org/10.1006/anbe.2000.1726

    • Google Scholar
93. 1. Lehmann L

    (2011) The demographic benefits of belligerence and bravery: Defeated group repopulation or victorious group size expansion?

    PLOS ONE 6:e21437.

    https://doi.org/10.1371/journal.pone.0021437

    • PubMed
    • Google Scholar
94. 1. Lemoine S
    2. Preis A
    3. Samuni L
    4. Boesch C
    5. Crockford C
    6. Wittig RM

    (2020) Between-group competition impacts reproductive success in wild chimpanzees

    Current Biology 30:312–318.

    https://doi.org/10.1016/j.cub.2019.11.039

    • PubMed
    • Google Scholar
95. Book

    1. Ligon JD
    2. Ligon SH

    (1990) Green woodhoopoes: Life history traits and sociality

    In: Stacey PB, Koenig WC, editors. Cooperative Breeding in Birds: Long-Term Studies of Ecology and Behavior. Cambridge: Cambridge University Press. pp. 33–65.

    https://doi.org/10.1017/CBO9780511752452.003

    • Google Scholar
96. 1. Mares R
    2. Young AJ
    3. Clutton-Brock TH

    (2012) Individual contributions to territory defence in a cooperative breeder: weighing up the benefits and costs

    Proceedings of the Royal Society B: Biological Sciences 279:3989–3995.

    https://doi.org/10.1098/rspb.2012.1071

    • PubMed
    • Google Scholar
97. 1. Markham AC
    2. Alberts SC
    3. Altmann J

    (2012) Intergroup conflict: Ecological predictors of winning and consequences of defeat in a wild primate population

    Animal Behaviour 82:399–403.

    https://doi.org/10.1016/j.anbehav.2012.05.009

    • PubMed
    • Google Scholar
98. 1. Marshall HH
    2. Vitikainen EIK
    3. Mwanguhya F
    4. Businge R
    5. Kyabulima S
    6. Hares MC
    7. Inzani E
    8. Kalema-Zikusoka G
    9. Mwesige K
    10. Nichols HJ
    11. Sanderson JL
    12. Thompson FJ
    13. Cant MA

    (2017) Lifetime fitness consequences of early-life ecological hardship in a wild mammal population

    Ecology and Evolution 7:1712–1724.

    https://doi.org/10.1002/ece3.2747

    • PubMed
    • Google Scholar
99. 1. McCormick MI

    (1998) Behaviorally induced maternal stress in a fish influences progeny quality by a hormonal mechanism

    Ecology 79:1873–1883.

    https://doi.org/10.1890/0012-9658(1998)079[1873:BIMSIA]2.0.CO;2

    • Google Scholar
100. 1. Mech LD
     2. Harper EK

     (2002)

     Differential use of a wolf, Canis lupus, pack territory edge and core

     Canadian Field-Naturalist 116:315–316.

     • Google Scholar
101. 1. Micheletti AJC
     2. Ruxton GD
     3. Gardner A

     (2017) Intrafamily and intragenomic conflicts in human warfare

     Proceedings of the Royal Society B: Biological Sciences 284:20162699.

     https://doi.org/10.1098/rspb.2016.2699

     • PubMed
     • Google Scholar
102. 1. Micheletti AJC
     2. Ruxton GD
     3. Gardner A

     (2020) The demography of human warfare can drive sex differences in altruism

     Evolutionary Human Sciences 2:1–15.

     https://doi.org/10.1017/ehs.2020.5

     • Google Scholar
103. 1. Mileva VR
     2. Gilmour KM
     3. Balshine S

     (2011) Effects of maternal stress on egg characteristics in a cooperatively breeding fish

     Comparative Biochemistry and Physiology Part A 158:22–29.

     https://doi.org/10.1016/j.cbpa.2010.08.017

     • PubMed
     • Google Scholar
104. 1. Milinski M

     (1985) Risk of predation of parasitized sticklebacks (Gasterosteus Aculeatus L.) under competition for food

     Behaviour 93:203–216.

     https://doi.org/10.1163/156853986X00883

     • Google Scholar
105. 1. Mirville MO
     2. Ridley AR
     3. Samedi JPM
     4. Vecellio V
     5. Ndagijimana F
     6. Stoinski TS
     7. Grueter CC

     (2020) Intragroup behavioral changes following intergroup conflict in mountain gorillas (Gorilla beringei beringei

     International Journal of Primatology 41:382–400.

     https://doi.org/10.1007/s10764-020-00130-1

     • Google Scholar
106. 1. Mitani JC
     2. Watts DP
     3. Amsler SJ

     (2010) Lethal intergroup aggression leads to territorial expansion in wild chimpanzees

     Current Biology 20:R507–R508.

     https://doi.org/10.1016/j.cub.2010.04.021

     • PubMed
     • Google Scholar
107. 1. Morris-Drake A
     2. Christensen C
     3. Kern JM
     4. Radford AN

     (2019) Experimental field evidence that out-group threats influence within-group behavior

     Behavioral Ecology 30:1425–1435.

     https://doi.org/10.1093/beheco/arz095

     • PubMed
     • Google Scholar
108. Thesis

     1. Morris-Drake A

     (2021)

     Consequences of within- and between-group conflict in dwarf mongooses

     University of Bristol.

     • Google Scholar
109. 1. Morris-Drake A
     2. Linden JF
     3. Kern JM
     4. Radford AN

     (2021) Extended and cumulative effects of experimentally induced intergroup conflict in a cooperatively breeding mammal

     Proceedings of the Royal Society B: Biological Science 288:20211743.

     https://doi.org/10.1098/rspb.2021.1743

     • PubMed
     • Google Scholar
110. 1. Morris-Drake A
     2. Kennedy P
     3. Braga Goncalves I
     4. Radford AN

     (2022) Variation between species, populations, groups and individuals in the fitness consequences of out-group conflict

     Philosophical Transactions of the Royal Society B: Biological Sciences 377:20210148.

     https://doi.org/10.1098/rstb.2021.0148

     • PubMed
     • Google Scholar
111. 1. Mosser A
     2. Packer C

     (2009) Group territoriality and the benefits of sociality in the African lion, Panthera leo

     Animal Behaviour 78:359–370.

     https://doi.org/10.1016/j.anbehav.2009.04.024

     • Google Scholar
112. 1. Müller CA
     2. Bell MBV

     (2009) Kidnapping and infanticide between groups of banded mongooses

     Mammalian Biology 74:315–318.

     https://doi.org/10.1016/j.mambio.2008.08.003

     • Google Scholar
113. 1. Nichols HJ
     2. Cant MA
     3. Sanderson JL

     (2015) Adjustment of costly extra-group paternity according to inbreeding risk in a cooperative mammal

     Behavioral Ecology 26:1486–1494.

     https://doi.org/10.1093/beheco/arv095

     • PubMed
     • Google Scholar
114. 1. Noguera JC
     2. Kim SY
     3. Velando A

     (2017) Family-transmitted stress in a wild bird

     PNAS 114:6794–6799.

     https://doi.org/10.1073/pnas.1706164114

     • PubMed
     • Google Scholar
115. 1. Nolan MP
     2. Delaplane KS

     (2016) Distance between honey bee Apis mellifera colonies regulates populations of Varroa destructor at a landscape scale

     Apidologie 2016:1–9.

     https://doi.org/10.1007/s13592-016-0443-9

     • PubMed
     • Google Scholar
116. 1. O’Brien CE
     2. Bellanger C
     3. Jozet-Alves C
     4. Mezrai N
     5. Darmaillacq A-S
     6. Dickel L
     7. Arkhipkin A

     (2018) Stressful conditions affect reproducing cuttlefish (Sepia officinalis), reducing egg output and quality

     ICES Journal of Marine Science 75:2060–2069.

     https://doi.org/10.1093/icesjms/fsy115

     • Google Scholar
117. 1. Packer C
     2. Pusey AE

     (1983) Adaptations of female lions to infanticide by incoming males

     The American Naturalist 121:716–728.

     https://doi.org/10.1086/284097

     • Google Scholar
118. 1. Padgett DA
     2. Sheridan JF
     3. Dorne J
     4. Berntson GG
     5. Candelora J
     6. Glaser R

     (1998) Social stress and the reactivation of latent herpes simplex virus type 1

     PNAS 95:7231–7235.

     https://doi.org/10.1073/pnas.95.12.7231

     • PubMed
     • Google Scholar
119. 1. Peck DT
     2. Seeley TD

     (2019) Mite bombs or robber lures? The roles of drifting and robbing in Varroa destructor transmission from collapsing honey bee colonies to their neighbors

     PLOS ONE 14:e0218392.

     https://doi.org/10.1371/journal.pone.0218392

     • PubMed
     • Google Scholar
120. 1. Pines M
     2. Swedell L

     (2011) Not without a fair fight: Failed abductions of females in wild hamadryas baboons

     Primates 52:249–252.

     https://doi.org/10.1007/s10329-011-0242-x

     • PubMed
     • Google Scholar
121. 1. Pisor AC
     2. Surbeck M

     (2019) The evolution of intergroup tolerance in nonhuman primates and humans

     Evolutionary Anthropology 28:210–223.

     https://doi.org/10.1002/evan.21793

     • PubMed
     • Google Scholar
122. 1. Pollock GB
     2. Rissing SW

     (1989) Intraspecific brood raiding, territoriality, and slavery in ants

     The American Naturalist 133:61–70.

     https://doi.org/10.1086/284901

     • Google Scholar
123. 1. Powell S
     2. Donaldson‐Matasci M
     3. Woodrow‐Tomizuka A
     4. Dornhaus A
     5. Wilson R

     (2017) Context‐dependent defences in turtle ants: Resource defensibility and threat level induce dynamic shifts in soldier deployment

     Functional Ecology 31:2287–2298.

     https://doi.org/10.1111/1365-2435.12926

     • Google Scholar
124. 1. Preston EFR
     2. Thompson FJ
     3. Ellis S
     4. Kyambulima S
     5. Croft DP
     6. Cant MA

     (2021) Network-level consequences of outgroup threats in banded mongooses: Grooming and aggression between the sexes

     The Journal of Animal Ecology 90:153–167.

     https://doi.org/10.1111/1365-2656.13323

     • PubMed
     • Google Scholar
125. 1. Pride RE

     (2005) High faecal glucocorticoid levels predict mortality in ring-tailed lemurs (Lemur catta)

     Biology Letters 1:60–63.

     https://doi.org/10.1098/rsbl.2004.0245

     • PubMed
     • Google Scholar
126. 1. Quan N
     2. Avitsur R
     3. Stark JL
     4. He LL
     5. Shah M
     6. Caligiuri M
     7. Padgett DA
     8. Marucha PT
     9. Sheridan JF

     (2001) Social stress increases the susceptibility to endotoxic shock

     Journal of Neuroimmunology 115:36–45.

     https://doi.org/10.1016/S0165-5728(01)00273-9

     • PubMed
     • Google Scholar
127. 1. Radford AN

     (2003) Territorial vocal rallying in the green woodhoopoe: Influence of rival group size and composition

     Animal Behaviour 66:1035–1044.

     https://doi.org/10.1006/anbe.2003.2292

     • Google Scholar
128. 1. Radford AN
     2. du Plessis MA

     (2004) Territorial vocal rallying in the green woodhoopoe: Factors affecting contest length and outcome

     Animal Behaviour 68:803–810.

     https://doi.org/10.1016/j.anbehav.2004.01.010

     • Google Scholar
129. 1. Radford AN

     (2008) Duration and outcome of intergroup conflict influences intragroup affiliative behaviour

     Proceedings of the Royal Society B: Biological Sciences 275:2787–2791.

     https://doi.org/10.1098/rspb.2008.0787

     • PubMed
     • Google Scholar
130. 1. Radford AN

     (2010) Preparing for battle? Potential intergroup conflict promotes current intragroup affiliation

     Biology Letters 7:26–29.

     https://doi.org/10.1098/rsbl.2010.0507

     • PubMed
     • Google Scholar
131. 1. Radford AN
     2. Fawcett TW

     (2014) Conflict between groups promotes later defense of a critical resource in a cooperatively breeding bird

     Current Biology 24:2935–2939.

     https://doi.org/10.1016/j.cub.2014.10.036

     • PubMed
     • Google Scholar
132. 1. Radford AN
     2. Majolo B
     3. Aureli F

     (2016) Within-group behavioural consequences of between-group conflict: A prospective review

     Proceedings of the Royal Society B: Biological Sciences 283:20161567.

     https://doi.org/10.1098/rspb.2016.1567

     • PubMed
     • Google Scholar
133. 1. Ridley AR
     2. Raihani NJ
     3. Nelson-Flower MJ

     (2008) The cost of being alone: The fate of floaters in a population of cooperatively breeding pied babblers Turdoides bicolor

     Journal of Avian Biology 39:389–392.

     https://doi.org/10.1111/j.0908-8857.2008.04479.x

     • Google Scholar
134. 1. Ridley AR

     (2011) Invading together: The benefits of coalition dispersal in a cooperative bird

     Behavioral Ecology and Sociobiology 66:77–83.

     https://doi.org/10.1007/s00265-011-1255-6

     • Google Scholar
135. Book

     1. Ridley AR

     (2016) Southern pied babblers: The dynamics of conflict and cooperation in a group-living society

     In: Koenig WC, Dickinson JL, editors. Cooperative Breeding in Vertebrates: Studies of Ecology, Evolution and Behavior. Cambridge: Cambridge University Press. pp. 115–132.

     https://doi.org/10.1017/CBO9781107338357.008

     • Google Scholar
136. 1. Ridley AR
     2. Nelson-Flower MJ
     3. Wiley EM
     4. Humphries DJ
     5. Kokko H

     (2022) Kidnapping intergroup young: An alternative strategy to maintain group size in the group-living pied babbler (Turdoides bicolor)

     Philosophical Transactions of the Royal Society B: Biological Sciences 377:20210153.

     https://doi.org/10.1098/rstb.2021.0153

     • PubMed
     • Google Scholar
137. 1. Robar N
     2. Burness G
     3. Murray DL

     (2010) Tropics, trophics and taxonomy: the determinants of parasite-associated host mortality

     Oikos 119:1273–1280.

     https://doi.org/10.1111/j.1600-0706.2009.18292.x

     • Google Scholar
138. 1. Roberts EK
     2. Lu A
     3. Bergman TJ
     4. Beehner JC

     (2012) A Bruce effect in wild geladas

     Science 335:1222–1225.

     https://doi.org/10.1126/science.1213600

     • PubMed
     • Google Scholar
139. 1. Roche DP
     2. McGhee KE
     3. Bell AM

     (2012) Maternal predator-exposure has lifelong consequences for offspring learning in threespined sticklebacks

     Biology Letters 8:932–935.

     https://doi.org/10.1098/rsbl.2012.0685

     • PubMed
     • Google Scholar
140. 1. Romero LM
     2. Dickens MJ
     3. Cyr NE

     (2009) The reactive scope model - A new model integrating homeostasis, allostasis, and stress

     Hormones and Behavior 55:375–389.

     https://doi.org/10.1016/j.yhbeh.2008.12.009

     • PubMed
     • Google Scholar
141. 1. Romero-Diaz C
     2. Gonzalez-Jimena V
     3. Fitze PS

     (2019) Corticosterone mediated mate choice affects female mating reluctance and reproductive success

     Hormones and Behavior 113:1–12.

     https://doi.org/10.1016/j.yhbeh.2019.04.011

     • PubMed
     • Google Scholar
142. 1. Rosenbaum S
     2. Vecellio V
     3. Stoinski T

     (2016) Observations of severe and lethal coalitionary attacks in wild mountain gorillas

     Scientific Reports 6:37018.

     https://doi.org/10.1038/srep37018

     • PubMed
     • Google Scholar
143. Book

     1. Rowley I
     2. Russell E

     (1990) Splendid Fairy-wrens: Demonstrating the importance of longevity

     In: Stacey PB, Koenig WD, editors. Cooperative Breeding in Birds: Long-Term Studies of Ecology and Behavior. Cambridge: Cambridge University Press. pp. 3–30.

     https://doi.org/10.1017/CBO9780511752452.002

     • Google Scholar
144. 1. Royle NJ
     2. Lindström J
     3. Metcalfe NB

     (2005) A poor start in life negatively affects dominance status in adulthood independent of body size in green swordtails Xiphophorus helleri

     Proceedings of the Royal Society B: Biological Sciences 272:1917–1922.

     https://doi.org/10.1098/rspb.2005.3190

     • PubMed
     • Google Scholar
145. Book

     1. Rubenstein DI
     2. Nuñez CM

     (2009) Sociality and reproductive skew in horses and zebras

     In: Hager R, Jones CB, editors. Reproductive Skew in Vertebrates: Proximate and Ultimate Causes. Cambridge: Cambridge University Press. pp. 196–226.

     https://doi.org/10.1017/CBO9780511641954.010

     • Google Scholar
146. 1. Rudolph KP
     2. McEntee JP

     (2016) Spoils of war and peace: Enemy adoption and queen-right colony fusion follow costly intraspecific conflict in acacia ants

     Behavioral Ecology 27:793–802.

     https://doi.org/10.1093/beheco/arv219

     • Google Scholar
147. 1. Rusch H

     (2014) The evolutionary interplay of intergroup conflict and altruism in humans: A review of parochial altruism theory and prospects for its extension

     Proceedings of the Royal Society B: Biological Sciences 281:20141539.

     https://doi.org/10.1098/rspb.2014.1539

     • PubMed
     • Google Scholar
148. 1. Rusch H
     2. Gavrilets S

     (2020) The logic of animal intergroup conflict: A review

     Journal of Economic Behavior & Organization 178:1014–1030.

     https://doi.org/10.1016/j.jebo.2017.05.004

     • Google Scholar
149. 1. Russell AF
     2. Young AJ
     3. Spong G
     4. Jordan NR
     5. Clutton-Brock TH

     (2007) Helpers increase the reproductive potential of offspring in cooperative meerkats

     Proceedings of the Royal Society B: Biological Sciences 274:513–520.

     https://doi.org/10.1098/rspb.2006.3698

     • PubMed
     • Google Scholar
150. 1. Samuni L
     2. Preis A
     3. Deschner T
     4. Wittig RM
     5. Crockford C

     (2019) Cortisol and oxytocin show independent activity during chimpanzee intergroup conflict

     Psychoneuroendocrinology 104:165–173.

     https://doi.org/10.1016/j.psyneuen.2019.02.007

     • PubMed
     • Google Scholar
151. 1. Samuni L
     2. Mielke A
     3. Preis A
     4. Crockford C
     5. Wittig RM

     (2020) Intergroup competition enhances chimpanzee (Pan troglodytes verus) in-group cohesion

     International Journal of Primatology 41:342–362.

     https://doi.org/10.1007/s10764-019-00112-y

     • Google Scholar
152. 1. Schindler S
     2. Radford AN

     (2018) Factors influencing within-group conflict over defence against conspecific outsiders seeking breeding positions

     Proceedings of the Royal Society B: Biological Sciences 285:20181669.

     https://doi.org/10.1098/rspb.2018.1669

     • PubMed
     • Google Scholar
153. 1. Schneider-Crease I
     2. Chiou KL
     3. Snyder-Mackler N
     4. Bergman TJ
     5. Beehner JC
     6. Lu A

     (2020) Beyond infant death: the hidden costs of male immigration in geladas

     Animal Behaviour 159:89–95.

     https://doi.org/10.1016/j.anbehav.2019.11.010

     • Google Scholar
154. 1. Schoof VAM
     2. Jack KM

     (2013) The association of intergroup encounters, dominance status, and fecal androgen and glucocorticoid profiles in wild male white-faced capuchins (Cebus capucinus)

     American Journal of Primatology 75:107–115.

     https://doi.org/10.1002/ajp.22089

     • PubMed
     • Google Scholar
155. 1. Schreck CB

     (2010) Stress and fish reproduction: The roles of allostasis and hormesis

     General and Comparative Endocrinology 165:549–556.

     https://doi.org/10.1016/j.ygcen.2009.07.004

     • PubMed
     • Google Scholar
156. 1. Scott ME

     (1988) The impact of infection and disease on animal populations: Implications for conservation biology

     Conservation Biology 2:40–56.

     https://doi.org/10.1111/j.1523-1739.1988.tb00334.x

     • Google Scholar
157. 1. Seiler N
     2. Boesch C
     3. Mundry R
     4. Stephens C
     5. Robbins MM

     (2017) Space partitioning in wild, non-territorial mountain gorillas: The impact of food and neighbours

     Royal Society Open Science 4:170720.

     https://doi.org/10.1098/rsos.170720

     • PubMed
     • Google Scholar
158. 1. Sicotte P
     2. Teichroeb JA
     3. Vayro JV
     4. Fox SA
     5. Bădescu I
     6. Wikberg EC

     (2017) The influence of male takeovers on female dispersal in Colobus vellerosus

     American Journal of Primatology 79:e22436.

     https://doi.org/10.1002/ajp.22436

     • PubMed
     • Google Scholar
159. 1. Spong GF
     2. Hodge SJ
     3. Young AJ
     4. Clutton-Brock TH

     (2008) Factors affecting the reproductive success of dominant male meerkats

     Molecular Ecology 17:2287–2299.

     https://doi.org/10.1111/j.1365-294X.2008.03734.x

     • PubMed
     • Google Scholar
160. 1. Stallcup JA
     2. Woolfenden GE

     (1978) Family status and contributions to breeding by Florida scrub jays

     Animal Behaviour 26:1144–1156.

     https://doi.org/10.1016/0003-3472(78)90104-5

     • Google Scholar
161. 1. Stein LR
     2. Bell AM

     (2012) Consistent individual differences in fathering in threespined stickleback Gasterosteus aculeatus

     Current Zoology 58:45–52.

     https://doi.org/10.1093/czoolo/58.1.45

     • PubMed
     • Google Scholar
162. 1. Strong MJ
     2. Sherman BL
     3. Riehl C

     (2018) Home field advantage, not group size, predicts outcomes of intergroup conflicts in a social bird

     Animal Behaviour 143:205–213.

     https://doi.org/10.1016/j.anbehav.2017.07.006

     • Google Scholar
163. 1. Taborsky M
     2. Brouwer L
     3. Heg D
     4. Bachar Z

     (2005) Large group size yields group stability in the cooperatively breeding cichlid Neolamprologus pulcher

     Behaviour 142:1615–1641.

     https://doi.org/10.1163/156853905774831891

     • Google Scholar
164. 1. Taborsky B
     2. Skubic E
     3. Bruintjes R

     (2007) Mothers adjust egg size to helper number in a cooperatively breeding cichlid

     Behavioral Ecology 18:652–657.

     https://doi.org/10.1093/beheco/arm026

     • Google Scholar
165. 1. Thompson ME
     2. Kahlenberg SM
     3. Gilby IC
     4. Wrangham RW

     (2007) Core area quality is associated with variance in reproductive success among female chimpanzees at Kibale National Park

     Animal Behaviour 73:501–512.

     https://doi.org/10.1016/j.anbehav.2006.09.007

     • Google Scholar
166. 1. Thompson FJ
     2. Marshall HH
     3. Vitikainen EIK
     4. Cant MA

     (2017) Causes and consequences of intergroup conflict in cooperative banded mongooses

     Animal Behaviour 126:31–40.

     https://doi.org/10.1016/j.anbehav.2017.01.017

     • Google Scholar
167. 1. Thompson FJ
     2. Hunt KL
     3. Wright K
     4. Rosengaus RB
     5. Cole EL
     6. Birch G
     7. Maune AL
     8. Cant MA

     (2020) Who goes there? Social surveillance as a response to intergroup conflict in a primitive termite

     Biology Letters 16:20200131.

     https://doi.org/10.1098/rsbl.2020.0131

     • Google Scholar
168. 1. Thorne BL
     2. Breisch NL
     3. Muscedere ML

     (2003) Evolution of eusociality and the soldier caste in termites: influence of intraspecific competition and accelerated inheritance

     PNAS 100:12808–12813.

     https://doi.org/10.1073/pnas.2133530100

     • PubMed
     • Google Scholar
169. 1. Tschinkel WR
     2. Howard DF

     (1983) Colony founding by pleometrosis in the fire ant, Solenopsis invicta

     Behavioral Ecology and Sociobiology 12:103–113.

     https://doi.org/10.1007/BF00343200

     • Google Scholar
170. 1. Van Belle S
     2. Grueter CC
     3. Furuichi T

     (2020) Dynamics of intergroup relationships in primates: Introduction to the special issue

     International Journal of Primatology 41:163–170.

     https://doi.org/10.1007/s10764-020-00159-2

     • Google Scholar
171. 1. Verdolin JL

     (2006) Meta-analysis of foraging and predation risk trade-offs in terrestrial systems

     Behavioral Ecology and Sociobiology 60:457–464.

     https://doi.org/10.1007/s00265-006-0172-6

     • Google Scholar
172. 1. Vitousek MN
     2. Jenkins BR
     3. Safran RJ

     (2014) Stress and success: Iindividual differences in the glucocorticoid stress response predict behavior and reproductive success under high predation risk

     Hormones and Behavior 66:812–819.

     https://doi.org/10.1016/j.yhbeh.2014.11.004

     • PubMed
     • Google Scholar
173. 1. Vitousek MN
     2. Taff CC
     3. Ardia DR
     4. Stedman JM
     5. Zimmer C
     6. Salzman TC
     7. Winkler DW

     (2018) The lingering impact of stress: Brief acute glucocorticoid exposure has sustained, dose-dependent effects on reproduction

     Proceedings of the Royal Society B: Biological Sciences 285:20180722.

     https://doi.org/10.1098/rspb.2018.0722

     • PubMed
     • Google Scholar
174. 1. Vuarin P
     2. Pillay N
     3. Schradin C

     (2019) Elevated basal corticosterone levels increase disappearance risk of light but not heavy individuals in a long-term monitored rodent population

     Hormones and Behavior 113:95–102.

     https://doi.org/10.1016/j.yhbeh.2019.05.001

     • PubMed
     • Google Scholar
175. 1. Walker LA
     2. York JE
     3. Young AJ

     (2016) Sexually selected sentinels? Evidence of a role for intrasexual competition in sentinel behavior

     Behavioral Ecology 27:1461–1470.

     https://doi.org/10.1093/beheco/arw064

     • PubMed
     • Google Scholar
176. 1. Wey TW
     2. Lin L
     3. Patton ML
     4. Blumstein DT

     (2014) Stress hormone metabolites predict overwinter survival in yellow-bellied marmots

     Acta Ethologica 18:181–185.

     https://doi.org/10.1007/s10211-014-0204-6

     • Google Scholar
177. 1. Wiley EM
     2. Ridley AR

     (2018) The benefits of pair bond tenure in the cooperatively breeding pied babbler (Turdoides bicolor)

     Ecology and Evolution 8:7178–7185.

     https://doi.org/10.1002/ece3.4243

     • PubMed
     • Google Scholar
178. 1. Wilson BS

     (1992) Tail injuries increase the risk of mortality in free-living lizards (Uta stansburiana

     Oecologia 92:145–152.

     https://doi.org/10.1007/BF00317275

     • PubMed
     • Google Scholar
179. 1. Wilson ML
     2. Boesch C
     3. Fruth B
     4. Furuichi T
     5. Gilby IC
     6. Hashimoto C
     7. Hobaiter CL
     8. Hohmann G
     9. Itoh N
     10. Koops K
     11. Lloyd JN
     12. Matsuzawa T
     13. Mitani JC
     14. Mjungu DC
     15. Morgan D
     16. Muller MN
     17. Mundry R
     18. Nakamura M
     19. Pruetz J
     20. Pusey AE
     21. Riedel J
     22. Sanz C
     23. Schel AM
     24. Simmons N
     25. Waller M
     26. Watts DP
     27. White F
     28. Wittig RM
     29. Zuberbühler K
     30. Wrangham RW

     (2014) Lethal aggression in Pan is better explained by adaptive strategies than human impacts

     Nature 513:414–417.

     https://doi.org/10.1038/nature13727

     • PubMed
     • Google Scholar
180. 1. Wong M
     2. Balshine S

     (2011) The evolution of cooperative breeding in the African cichlid fish, Neolamprologus pulcher

     Biological Reviews 86:511–530.

     https://doi.org/10.1111/j.1469-185X.2010.00158.x

     • PubMed
     • Google Scholar
181. 1. Wrangham RW
     2. Wilson ML
     3. Muller MN

     (2006) Comparative rates of violence in chimpanzees and humans

     Primates 47:14–26.

     https://doi.org/10.1007/s10329-005-0140-1

     • PubMed
     • Google Scholar
182. 1. Young AJ
     2. Spong G
     3. Clutton-Brock T

     (2007) Subordinate male meerkats prospect for extra-group paternity: Alternative reproductive tactics in a cooperative mammal

     Proceedings of the Royal Society B: Biological Sciences 274:1603–1609.

     https://doi.org/10.1098/rspb.2007.0316

     • PubMed
     • Google Scholar
183. Book

     1. Zahavi A

     (1990) Arabian babblers: The quest for social status in a cooperative breeder

     In: Stacey PB, Koenig WD, editors. Cooperative Breeding in Birds: Long-Term Studies of Ecology and Behavior. Cambridge: Cambridge University Press. pp. 105–130.

     https://doi.org/10.1017/CBO9780511752452.005

     • Google Scholar
184. 1. Zanette LY
     2. White AF
     3. Allen MC
     4. Clinchy M

     (2011) Perceived predation risk reduces the number of offspring songbirds produce per year

     Science 334:1398–1401.

     https://doi.org/10.1126/science.1210908

     • PubMed
     • Google Scholar
185. 1. Zipple MN
     2. Grady JH
     3. Gordon JB
     4. Chow LD
     5. Archie EA
     6. Altmann J
     7. Alberts SC

     (2017) Conditional fetal and infant killing by male baboons

     Proceedings of the Royal Society B: Biological Sciences 284:20162561.

     https://doi.org/10.1098/rspb.2016.2561

     • PubMed
     • Google Scholar

Author details

1. Ines Braga Goncalves

   School of Biological Sciences, University of Bristol, Bristol, United Kingdom

   Contribution

   Conceptualization, Visualization, Writing – original draft, Writing – review and editing

   Contributed equally with

   Amy Morris-Drake, Patrick Kennedy and Andrew N Radford

   Competing interests

   No competing interests declared

   "This ORCID iD identifies the author of this article:" 0000-0003-0659-9029

2. Amy Morris-Drake

   School of Biological Sciences, University of Bristol, Bristol, United Kingdom

   Contribution

   Conceptualization, Visualization, Writing – original draft, Writing – review and editing

   Contributed equally with

   Ines Braga Goncalves, Patrick Kennedy and Andrew N Radford

   Competing interests

   No competing interests declared

   "This ORCID iD identifies the author of this article:" 0000-0003-4243-4651

3. Patrick Kennedy

   School of Biological Sciences, University of Bristol, Bristol, United Kingdom

   Contribution

   Conceptualization, Visualization, Writing – original draft, Writing – review and editing

   Contributed equally with

   Ines Braga Goncalves, Amy Morris-Drake and Andrew N Radford

   Competing interests

   No competing interests declared

4. Andrew N Radford

   School of Biological Sciences, University of Bristol, Bristol, United Kingdom

   Contribution

   Conceptualization, Funding acquisition, Visualization, Writing – original draft, Writing – review and editing

   Contributed equally with

   Ines Braga Goncalves, Amy Morris-Drake and Patrick Kennedy

   For correspondence

   andy.radford@bristol.ac.uk

   Competing interests

   No competing interests declared

   "This ORCID iD identifies the author of this article:" 0000-0001-5470-3463

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