Find research datasets worth reusing

Data from: Alarm calls of a cooperative bird are referential and elicit context-specific antipredator behavior

Although functionally referential signals have been extensively studied, largely in mammals (e.g., nonhuman primates, see Cheney and Seyfarth (1988); mongooses, see Manser et al. (2002); and other ground-dwelling species, see Blumstein and Armitage (1997), other social taxa such as birds would similarly benefit from the use of referential signals. We therefore investigated alarm calling in the cooperative noisy miner (Manorina melanocephala), a species that has been anecdotally recorded producing aerial alarms to flying predators and empirically recorded generating terrestrial alarms to ground-based threats. For these signals to be truly referential however, they must meet 3 criteria. First, calls must be structurally distinct, a requirement that these 2 call types meet. Second, calls must be stimulus-specific and reliably associated with a given stimulus. We tested this on free-living birds by exposing them to a simulated aerial predator that was either in flight or subsequently perched and thus presented one of the first studies on functionally referential alarm systems where both aerial and terrestrial alarm calls have been tested. Miners only produced aerial alarms while the stimulus was in flight, switching to terrestrial alarms once it landed. Third, referential signals must elicit different escape responses that are "appropriate" to the associated threat. Under field conditions, aerial alarm playback alone provoked an almost instantaneous response of fleeing to vegetation cover, whereas terrestrial alarm playback elicited significantly slower responses by receivers and an increase in scanning behavior. During laboratory experiments, aerial alarms stimulated birds to spend more time looking upwards, whereas terrestrial alarm calls stimulated individuals to scan perpendicularly, as expected if these stimuli provided information on likely predator location. Although other avian taxa have been shown to use referential alarm signals, this system provides novel evidence of referential calls based on the behavior rather than the type of predator, providing a highly adaptive means of communicating risk to other members of the social group in this cooperative species.

opencc-zeroDec 2018View details →

Data from: Context-dependent strategies of food allocation among offspring in a facultative cooperative breeder

Natural selection should favor adoption of parental strategies that maximize fitness when allocating investment among offspring. In birds, begging displays often convey information of nestling need and quality, allowing parents to make adaptive food allocation decisions. We investigated how adults utilized cues likely to represent nestling competitive ability (begging position) and need (begging intensity), and a cue independent of nestling control (nestling sex) to distribute food among nestlings in a facultative cooperative breeder, the black-throated tit (Aegithalos concinnus). We found that parents reduced their efforts when helped, suggesting that parents of helped broods would have the potential to satisfy nestling needs more than unhelped parents. This suggestion was supported by the fact that nestling mass increased faster in helped than in unhelped nests. We found no effect of nestling sex on food allocation, but, as predicted, we found that adults responded differently to begging signals in relation to the presence of helpers and brood size. First, helped parents were more responsive to nestling begging intensity than parents without helpers. Second, female parents and helpers had a stronger preference for nestling begging position in large than in small broods. Third, the preference for nestling begging position was greater for unhelped than for helped female parents. These results provide evidence that carers adjust their preference for different offspring begging signals based on availability of food resources.

opencc-zeroDec 2015View details →

Data from: Delayed dispersal and the costs and benefits of different routes to independent breeding in a cooperatively breeding bird

Why sexually mature individuals stay in groups as nonreproductive subordinates is central to the evolution of sociality and cooperative breeding. To understand such delayed dispersal, its costs and benefits need to be compared with those of permanently leaving to float through the population. However, comprehensive comparisons, especially regarding differences in future breeding opportunities, are rare. Moreover, extraterritorial prospecting by philopatric individuals has generally been ignored, even though the factors underlying this route to independent breeding may differ from those of strict philopatry or floating. We use a comprehensive predictive framework to explore how various costs, benefits and intrinsic, environmental and social factors explain philopatry, prospecting, and floating in Seychelles warblers (Acrocephalus sechellensis). Not only floaters more likely obtained an independent breeding position before the next season than strictly philopatric individuals, but also suffered higher mortality. Prospecting yielded similar benefits to floating but lower mortality costs, suggesting that it is overall more beneficial than floating and strict philopatry. While prospecting is probably individual-driven, although limited by resource availability, floating likely results from eviction by unrelated breeders. Such differences in proximate and ultimate factors underlying each route to independent breeding highlight the need for simultaneous consideration when studying the evolution of delayed dispersal.

opencc-zeroDec 2011View details →

Data from: Bacterial quorum sensing and metabolic incentives to cooperate

The opportunistic pathogen Pseudomonas aeruginosa uses a cell-cell communication system termed "quorum sensing" to control production of public goods, extracellular products that can be used by any community member. Not all individuals respond to quorum-sensing signals and synthesize public goods. Such social cheaters enjoy the benefits of the products secreted by cooperators. There are some P. aeruginosa cellular enzymes controlled by quorum sensing, and we show that quorum sensing–controlled expression of such private goods can put a metabolic constraint on social cheating and prevent a tragedy of the commons. Metabolic constraint of social cheating provides an explanation for private-goods regulation by a cooperative system and has general implications for population biology, infection control, and stabilization of quorum-sensing circuits in synthetic biology.

opencc-zeroJul 2019View details →

Data from: Reproductive conflict resolution in cooperative breeders

Female infanticide is common in animal societies where groups comprise multiple co-breeding females. To reduce the risk that their offspring are killed, mothers can synchronize breeding and pool offspring, making it hard for females to avoid killing their own young. However, female reproductive conflict does not invariably result in reproductive synchrony, and we lack a general hypothesis explaining the variation in conflict resolution strategies seen across species. Here, we investigate the fitness consequences of birth timing relative to other females and the prevalence of birth synchrony in cooperatively breeding Kalahari meerkats (Suricata suricatta). We show that, although there would be substantial benefits to females in synchronizing births and reducing their risk of infanticide, birth synchrony is rare. Since precise breeding synchrony has evolved in a related species with similar infanticidal female reproductive conflict, its absence in meerkats requires an evolutionary explanation. We therefore explore the costs and benefits of synchronizing breeding in two theoretical models, each of which contrasts synchrony with an alternative reproductive strategy: (i) breeding opportunistically and accepting fitness losses to infanticide or (ii) suppressing the reproduction of others to prevent infanticide. Our models show that the costs of synchrony constrain its development if subordinates breed infrequently, and that selection instead favours the suppression of subordinate reproduction by the dominant and opportunistic reproduction by subordinates. Together, our results suggest that the resolution of reproductive conflict in animal societies is shaped by differential breeding propensities among female group members, leading to divergent conflict resolution strategies even in closely-related species.

Data from: Social learning and the demise of costly cooperation in humans

Humans have a sophisticated ability to learn from others, termed social learning, which has allowed us to spread over the planet, construct complex societies, and travel to the moon. It has been hypothesized that social learning has played a pivotal role in making human societies cooperative, by favouring cooperation even when it is not favoured by genetical selection. However, this hypothesis lacks direct experimental testing, and the opposite prediction has also been made, that social learning disfavours cooperation. We experimentally tested how different aspects of social learning affect the level of cooperation in public-goods games. We found that: (i) social information never increased cooperation and usually led to decreased cooperation; (ii) cooperation was lowest when individuals could observe how successful individuals behaved; and (iii) cooperation declined because individuals preferred to copy successful individuals, who cooperated less, rather than copy common behaviours. Overall, these results suggest that individuals use social information to try and improve their own success, and that this can lead to lower levels of cooperation.

Data from: Rearing group size determines social competence and brain structure in a cooperatively breeding cichlid

Social animals can greatly benefit from well-developed social skills. Because the frequency and diversity of social interactions often increase with the size of social groups, the benefits of advanced social skills can be expected to increase with group size. Variation in social skills often arises during ontogeny, depending on early social experience. Whether variation of social-group sizes affects development of social skills and related changes in brain structures remains unexplored. We investigated whether, in a cooperatively breeding cichlid, early group size (1) shapes social behavior and social skills and (2) induces lasting plastic changes in gross brain structures and (3) whether the development of social skills is confined to a sensitive ontogenetic period. Rearing-group size and the time juveniles spent in these groups interactively influenced the development of social skills and the relative sizes of four main brain regions. We did not detect a sensitive developmental period for the shaping of social behavior within the 2-month experience phase. Instead, our results suggest continuous plastic behavioral changes over time. We discuss how developmental effects on social behavior and brain architecture may adaptively tune phenotypes to their current or future environments.

opencc-zeroDec 2015View details →

Data from: Effectiveness of diagnostic screening tests in mass screening for COPD using a cooperative regional system in a region with heavy air pollution: a cross-sectional study

Objective: This research aimed to evaluate the effectiveness of a cooperative health care model for early detection and diagnosis of chronic obstructive pulmonary disease (COPD), in Omuta Japan. Methods: This was a cross-sectional observational study. We performed diagnosis of COPD at four public health centres in Omuta, Japan from March 2015 to March 2016, by adding screening for COPD at the time of routine medical evaluations. All patients over 50 years were eligible to participate. Of a total of 397 eligible patients, 293 agreed to take part in the study. Results: The estimated prevalence of COPD in Omuta was 10% among subjects over 40 years and was 17% among smokers. Out of those who were screened, over half had questionnaire scores over the cut-off of 17 points and decreased FEV1/FVC%, indicating COPD (p>0.05). Thirty subjects with suspected COPD were given a referral for further investigation at a local central hospital, but only six underwent further medical examinations. Conclusion: The combination of COPD questionnaire and medical exam was effective as a COPD screening tool. Future research should investigate behavioural interventions for smoking cessation that can be offered in a cooperative model, as well as for improving participation in COPD screening and for encouraging early presentation for treatment in those suspected of having COPD.

opencc-zeroDec 2013View details →

Data from: Interspecific signalling between mutualists: food-thieving drongos use a cooperative sentinel call to manipulate foraging partners

Interspecific communication is common in nature, particularly between mutualists. However, whether signals evolved for communication with other species, or are in fact conspecific signals eavesdropped upon by partners, is often unclear. Fork-tailed drongos (Dicrurus adsimilis) associate with mixed-species groups and often produce true alarms at predators, whereupon associating species flee to cover, but also false alarms to steal associating species' food (kleptoparasitism). Despite such deception, associating species respond to drongo non-alarm calls by increasing their foraging and decreasing vigilance. Yet, whether these calls represent interspecific sentinel signals remains unknown. We show that drongos produced a specific sentinel call when foraging with a common associate, the sociable weaver (Philetairus socius), but not when alone. Weavers increased their foraging and decreased vigilance when naturally associating with drongos, and in response to sentinel call playback. Further, drongos sentinel-called more often when weavers were moving, and weavers approached sentinel calls, suggesting a recruitment function. Finally, drongos sentinel-called when weavers fled following false alarms, thereby reducing disruption to weaver foraging time. Results therefore provide evidence of an 'all clear' signal that mitigates the cost of inaccurate communication. Our results suggest that drongos enhance exploitation of a foraging mutualist through coevolution of interspecific sentinel signals.

Data from: The oxidative costs of reproduction are group-size dependent in a wild cooperative breeder

Life-history theory assumes that reproduction entails a cost, and research on cooperatively breeding societies suggests that the cooperative sharing of workloads can reduce this cost. However, the physiological mechanisms that underpin both the costs of reproduction and the benefits of cooperation remain poorly understood. It has been hypothesised that reproductive costs may arise in part from oxidative stress, as reproductive investment may elevate exposure to reactive oxygen species, compromising survival and future reproduction and accelerating senescence. However, experimental evidence of oxidative costs of reproduction in the wild remains scarce. Here, we use a clutch-removal experiment to investigate the oxidative costs of reproduction in a wild cooperatively breeding bird, the white-browed sparrow weaver, Plocepasser mahali. Our results reveal costs of reproduction that are dependent on group size: relative to individuals in groups whose eggs were experimentally removed, individuals in groups that raised offspring experienced an associated cost (elevated oxidative damage and reduced body mass), but only if they were in small groups containing fewer or no helpers. Furthermore, during nestling provisioning, individuals that provisioned at higher rates showed greater within-individual declines in body mass and antioxidant protection. Our results provide rare experimental evidence that reproduction can negatively impact both oxidative status and body mass in the wild, and suggest that these costs can be mitigated in cooperative societies by the presence of additional helpers. These findings have implications for our understanding of the energetic and oxidative costs of reproduction, and the benefits of cooperation in animal societies.

Data from: Negative association between parental care and sibling cooperation in earwigs: a new perspective on the early evolution of family life?

The evolution of family life requires net fitness benefits for offspring, which are commonly assumed to mainly derive from parental care. However, an additional source of benefits for offspring is often overlooked: cooperative interactions among juvenile siblings. In this study, we examined how sibling cooperation and parental care could jointly contribute to the early evolution of family life. Specifically, we tested whether the level of food transferred among siblings (sibling cooperation) in the European earwig Forficula auricularia (1) depends on the level of maternal food provisioning (parental care), and (2) is translated into offspring survival, as well as female investment into future reproduction. We show that higher levels of sibling food transfer were associated with lower levels of maternal food provisioning, possibly reflecting a compensatory relationship between sibling cooperation and maternal care. Furthermore, the level of sibling food transfer did not influence offspring survival, but was associated with negative effects on the production of the second and terminal clutch by the tending mothers. These findings indicate that sibling cooperation could mitigate the detrimental effects on offspring survival that result from being tended by low quality mothers. More generally, they are in line with the hypothesis that sibling cooperation is an ancestral behavior that can be retained to compensate for insufficient levels of parental investment.

Data from: Why hate the good guy? Antisocial punishment of high cooperators is greater when people compete to be chosen

When choosing social partners, people prefer good cooperators (all else equal). Given this preference, anyone wishing to be chosen can either increase their own cooperation to become more desirable, or suppress others' cooperation to make them less desirable. Previous research shows that very cooperative people sometimes get punished ("antisocial punishment") or criticized ("do-gooder derogation") in many cultures. Here we use a public goods game with punishment to test whether antisocial punishment is used as a means of competing to be chosen by suppressing others' cooperation. As predicted, there was more antisocial punishment when participants were competing to be chosen for a subsequent cooperative task (a Trust Game) than without a subsequent task. This difference in antisocial punishment cannot be explained by differences in contributions, moralistic punishment, or confusion. This suggests that antisocial punishment is a social strategy that low cooperators use to avoid looking bad when high cooperators escalate cooperation.

Data from: Out-group threat promotes within-group affiliation in a cooperative fish

In social species, conflict with outsiders is predicted to affect within-group interactions, and thus influence group dynamics and the evolution and maintenance of sociality. While empirical evidence exists for a relationship between out-group conflict and intragroup behaviour in humans, experimental tests in other animals are rare. In a model fish system, we show that simulated out-group intrusions cause post-conflict increases in intragroup affiliation, but no changes in post-conflict intragroup aggression. Post-conflict affiliation was greater following intrusions by neighbouring compared to non-neighbouring individuals; neighbours represent greater threats to the dominance rank and breeding success of residents, and are visible in the aftermath of the intrusion. By providing strong evidence of a link between out-group conflict and post-conflict intragroup behaviour, and demonstrating that intragroup affiliation is affected by the nature of the out-group intrusion, our study shows the importance of considering post-conflict behaviour for our understanding of cooperation and social structure.

opencc-zeroMay 2020View details →

Data from: Evolution of conditional cooperation in public good games

<p class="Standard">It is observed that in a repeated public good game with same individuals, free riding by a few individuals in the initial rounds triggers free riding by others in the subsequent rounds. It is presumed that individuals tend to imitate social behaviour of successful or relatively high payoff individuals, irrespective of how the payoffs were obtained. However, humans are concerned about how the payoffs were obtained, such as whether the payoffs were obtained by cheating or good behaviour. Individuals are willing to incur certain cost in order to improve group benefits and these individuals gain prestige. In human societies individuals tend to imitate social behaviour of high prestige agents. We propose that when agents are aware of other agents' payoffs scores and their prestige, perhaps agents are more likely to imitate social behaviour of high prestige and high payoff agents. We introduce, population level affinity parameters such as affinity towards payoff and affinity towards prestige of role models. We show that, for certain affinity parameters, high levels of cooperation are established in a population consisting of heterogeneous conditional co-operators, when agents imitate social behaviour of high prestige and high payoff agents. The proposed model provides insights into why value-based societies are more successful than competitive societies in establishing cooperation.</p>

Data from: Social setting, intuition and experience in laboratory experiments interact to shape cooperative decision-making

Recent studies suggest that cooperative decision-making in one-shot interactions is a history-dependent dynamic process: promoting intuition versus deliberation typically has a positive effect on cooperation (dynamism) among people living in a cooperative setting and with no previous experience in economic games on cooperation (history dependence). Here, we report on a laboratory experiment exploring how these findings transfer to a non-cooperative setting. We find two major results: (i) promoting intuition versus deliberation has no effect on cooperative behaviour among inexperienced subjects living in a non-cooperative setting; (ii) experienced subjects cooperate more than inexperienced subjects, but only under time pressure. These results suggest that cooperation is a learning process, rather than an instinctive impulse or a self-controlled choice, and that experience operates primarily via the channel of intuition. Our findings shed further light on the cognitive basis of human cooperative decision-making and provide further support for the recently proposed social heuristics hypothesis.

Data from: Evidence for strategic cooperation in humans

Humans may cooperate strategically, cooperating at higher levels than expected from their short-term interests, to try and stimulate others to cooperate. To test this hypothesis, we experimentally manipulated the extent an individual's behaviour is known to others, and hence whether or not strategic cooperation is possible. In contrast with many previous studies, we avoided confounding factors by preventing individuals from learning during the game about either pay-offs or about how other individuals behave. We found clear evidence for strategic cooperators—just telling some individuals that their groupmates would be informed about their behaviour led to them tripling their initial level of cooperation, from 17 to 50%. We also found that many individuals play as if they do not understand the game, and their presence obscures the detection of strategic cooperation. Identifying such players allowed us to detect and study strategic motives for cooperation in novel, more powerful, ways.

opencc-zeroDec 2010View details →

Data from: Cost of cooperation rules selection for cheats in bacterial metapopulations

Bacteria secrete a large variety of beneficial metabolites into the environment, which can be shared as public goods among producing bacteria, but also be exploited by non-producing cheats. Here, we focus on cooperative production of iron-chelating molecules (siderophores) in the bacterium Pseudomonas aeruginosa to study how relevant ecological factors influence selection for cheating. We designed patch-structured metapopulations that allowed us introducing among-patch ecological variation. We found that cheating readily evolved in uniform iron-limited environments. This finding is explained by severe iron limitation demanding high siderophore-production efforts, which results in high metabolic costs accruing to cooperators, and thereby facilitates the spread of cheats. In contrast, we observed a significant reduction or even negation of selection for cheating in metapopulations where we introduced patches with increased iron availability and/or opportunities to recycle siderophores. These findings are compatible with the view that cheats are less likely to invade in environments that allow bacteria to reduce siderphore-production efforts, as this lowers the overall metabolic costs accruing to cooperators. Because we increased iron availability and siderophore recycling opportunities moderately, and only in some patches, our findings demonstrate that already small local variations in ecological conditions as occurring in nature can significantly affect selection for public-good secretion in microbes. In addition, we found that most (84.6%) of the evolved cheats were partially deficient for siderophore production and not loss-of-function mutants. Genetic considerations indicate that mutations leading to partial deficiency occur more frequent than mutations leading to loss of function, but also suggest that partially-deficient mutants might often be the more competitive cheats.

Data from: Defector clustering is linked to cooperation in a pathogenic bacterium

Spatial clustering is thought to favour the evolution of cooperation because it puts cooperators in a position to help each other. However, clustering also increases competition. The fate of cooperation may depend on how much cooperators cluster relative to defectors, but these clustering differences have not been the focus of previous models and experiments. By competing siderophore-producing cooperator and defector strains of the opportunistic pathogen Pseudomonas aeruginosa in experimental microhabitats, we found that at the spatial scale of individual interactions, cooperator clustering lowers cooperation, but defector clustering favours cooperation. A theoretical model and individual-based simulations show these counterintuitive effects can arise when competition and cooperation occur at a single resource-determined scale, with population dynamics crucially allowing cooperators and defectors to cluster differently. The results suggest that cooperation relies on the regulation of sufficient defector clustering relative to cooperator clustering, which may be important in bacteria, social amoeba, and cancer inhibition.

opencc-zeroDec 2017View details →

Data from: Aspiration-based coevolution of link weights promotes cooperation in the spatial prisoner's dilemma game

In this article, we propose an aspiration-based coevolution of link weights, and we explore how this affects the evolution of cooperation in the spatial prisoner's dilemma game. In particular, an individual will increase the weight of its link to its neighbors only if the payoff received via this interaction will exceed a pre-defined aspiration. Conversely, if the received payoff is below this aspiration, the link weight with the corresponding neighbor will be decreased. Our simulation results show that an appropriate aspiration level leads to a high-cooperation plateau, whereas a too high or a too low aspiration will impede the evolution of cooperation. We explain these findings with a comprehensive analysis of transition points and with a systematic analysis of typical configuration patterns. The presented results provide further theoretical insights with regards to the impact of different aspiration levels on cooperation in human societies.