Cumulative effects of body size and social experience on aggressive behaviour in a subsocial bee

Behaviour ◽  
2016 ◽  
Vol 153 (12) ◽  
pp. 1365-1385 ◽  
Author(s):  
Jacob R. Withee ◽  
Sandra M. Rehan

Dominance hierarchies represent some of nature’s most rudimentary social structures, and aggression is key to their establishment in many animal species. Previous studies have focused on the relative influences of prior experience and physiological traits of individuals in determining social rank through aggression. Here we examine the behavioural potential for dominance hierarchy formation in the subsocial small carpenter bee, Ceratina calcarata. Both physiological traits and social experience were found to play partial roles in predicting future interactive behaviour in this species. Our results suggest that individual size is associated with dominance in initial encounters, while prior experience plays a larger role in predicting dominance in subsequent encounters. Social systems in the early stages of social evolution may well have followed these same predictive factors and these factors are key targets for future studies of social evolution and the behavioural origins of dominance hierarchies.

2019 ◽  
Vol 286 (1906) ◽  
pp. 20190536 ◽  
Author(s):  
Matthew J. Silk ◽  
Michael A. Cant ◽  
Simona Cafazzo ◽  
Eugenia Natoli ◽  
Robbie A. McDonald

Dominance hierarchies are widespread in animal societies and reduce the costs of within-group conflict over resources and reproduction. Variation in stability across a social hierarchy may result in asymmetries in the benefits obtained from hierarchy formation. However, variation in the stability and behavioural costs of dominance interactions with rank remain poorly understood. Previous theoretical models have predicted that the intensity of dominance interactions and aggression should increase with rank, but these models typically assume high reproductive skew, and so their generality remains untested. Here we show in a pack of free-living dogs with a sex–age-graded hierarchy that the central region of the hierarchy was dominated by more unstable social relationships and associated with elevated aggression. Our results reveal unavoidable costs of ascending a dominance hierarchy, run contrary to theoretical predictions for the relationship between aggression and social rank in high-skew societies, and widen our understanding of how heterogeneous benefits of hierarchy formation arise in animal societies.


2021 ◽  
Author(s):  
T Rueger ◽  
SJ Heatwole ◽  
MY Wong

AbstractMany animal groups consist of individuals organised in dominance hierarchies, based on age, size or fighting ability. Lower ranked individuals often do not reproduce themselves but perform cooperative behaviours to help the reproductive output of dominant individuals or the group as a whole. Theoretical models suggest that individuals of higher rank should show increased amounts of aggressive behaviours, such as aggressions towards other group members, but should decrease the amount of cooperative behaviours, such as brood care or territory maintenance. Most empirical tests of these models focus on insect or mammalian systems where kin selection plays a large role, rather than animals that live in groups of unrelated individuals. Here we use two anemonefish species to test hypotheses of variation in cooperation and aggression with respect to social rank and species, for social systems where group members are unrelated. We assessed the behaviours of each rank in 20 groups of Amphiprion percula and 12 groups of A. perideraion in Kimbe Bay, Papua New Guinea. We also performed a removal experiment to test if cooperative and aggressive behaviours are likely adaptive, i.e., if they change as an individual ascends in rank. Our results show differences between the two species, with A. percula showing more cooperative behaviours and A. perideraion showing more aggressive behaviours, despite them being closely related and sharing a very similar ecology. With respect to both cooperation and aggression we found consistent differences between ranks in both species, with higher ranks performing more aggressive as well as more cooperative behaviours. When we experimentally provided lower ranked individuals (rank 4) an opportunity to ascend in the hierarchy, they showed more aggression and more cooperation in line with our observations for rank 3 individuals. Thus, we show that rank specific behavioural patterns are likely adaptive in anemonefishes and that some model predictions do not hold in systems where kin selection benefits are absent. Rather, future fitness benefits through territory inheritance and group augmentation likely motivate cooperative and aggressive behaviours by subordinates in groups of unrelated vertebrates.


2019 ◽  
Author(s):  
Sam G. B. Roberts ◽  
Anna Roberts

Group size in primates is strongly correlated with brain size, but exactly what makes larger groups more ‘socially complex’ than smaller groups is still poorly understood. Chimpanzees (Pan troglodytes) and gorillas (Gorilla gorilla) are among our closest living relatives and are excellent model species to investigate patterns of sociality and social complexity in primates, and to inform models of human social evolution. The aim of this paper is to propose new research frameworks, particularly the use of social network analysis, to examine how social structure differs in small, medium and large groups of chimpanzees and gorillas, to explore what makes larger groups more socially complex than smaller groups. Given a fission-fusion system is likely to have characterised hominins, a comparison of the social complexity involved in fission-fusion and more stable social systems is likely to provide important new insights into human social evolution


2016 ◽  
Vol 8 (5) ◽  
pp. 1401-1410 ◽  
Author(s):  
Sandra M. Rehan ◽  
Karl M. Glastad ◽  
Sarah P. Lawson ◽  
Brendan G. Hunt

Author(s):  
Elizabeth A. Tibbetts ◽  
Juanita Pardo-Sanchez ◽  
Chloe Weise

Animal groups are often organized hierarchically, with dominant individuals gaining priority access to resources and reproduction over subordinate individuals. Initial dominance hierarchy formation may be influenced by multiple interacting factors, including an animal's individual attributes, conventions and self-organizing social dynamics. After establishment, hierarchies are typically maintained over the long-term because individuals save time, energy and reduce the risk of injury by recognizing and abiding by established dominance relationships. A separate set of behaviours are used to maintain dominance relationships within groups, including behaviours that stabilize ranks (punishment, threats, behavioural asymmetry), as well as signals that provide information about dominance rank (individual identity signals, signals of dominance). In this review, we describe the behaviours used to establish and maintain dominance hierarchies across different taxa and types of societies. We also review opportunities for future research including: testing how self-organizing behavioural dynamics interact with other factors to mediate dominance hierarchy formation, measuring the long-term stability of social hierarchies and the factors that disrupt hierarchy stability, incorporating phenotypic plasticity into our understanding of the behavioural dynamics of hierarchies and considering how cognition coevolves with the behaviours used to establish and maintain hierarchies. This article is part of the theme issue ‘The centennial of the pecking order: current state and future prospects for the study of dominance hierarchies’.


2003 ◽  
Vol 81 (7) ◽  
pp. 1269-1281 ◽  
Author(s):  
Francesca Gherardi ◽  
William H Daniels

In the eastern white river crayfish, Procambarus acutus acutus, the processes that act during hierarchy formation were explored by analyzing the behavior of 23 symmetric pairs of form I males. The experimental design comprised three subsequent phases: isolation, familiarization, and experimental phases. In the latter, pairs were formed of (i) unfamiliar opponents having different status, (ii, iii) unfamiliar opponents having the same status, either two alphas or two betas, and (iv) familiar opponents. The first result was that P. a. acutus is capable of establishing stable dominance hierarchies. Secondly, behavioral differences between the winners and the losers, a fast assessment of status, and self-reinforcing effects of recent experience were demonstrated. Thirdly, P. a. acutus was found to recognize the status of its rival but not its individual identity. In fact, even if paired with unfamiliar opponents, previous winners and losers behaved as in the preceding days. Conversely, both frequency and intensity of fighting increased when individuals of the same rank were opposed. These phenomena might be a consequence of "winning and losing effects". However, the increased readiness of former betas to attack contradicts the loser effect and validates the hypothesis of status recognition.


Behaviour ◽  
2017 ◽  
Vol 154 (6) ◽  
pp. 651-675
Author(s):  
K.P. Little ◽  
L. Al-Shaer ◽  
M. Itzkowitz

For species in which individuals spend at least some time in groups, dominance relationships and various social cues are often important for mate assessment and choice. For pair bonding species, social experiences may affect reproductive decisions in both sexes. We tested whether prior experience in a mixed-sex group and having a higher dominance status coincides with faster pair formation or spawning in a monogamous fish. Individuals having prior experience in mixed-sex groups paired with a novel fish more frequently than fish from same-sex groups. Fish in mixed-sex groups performed more bites and lateral displays. Although spawning occurred infrequently across pairs, dominant fish from mixed-sex groups spawned more than dominant fish from same-sex groups. Otherwise, there were no clear behavioural relationships between treatment group and subsequent pair formation or spawning, nor were behaviours of the paired fishes related to their prior treatment group. We do not know how mixed-sex social experience may have affected the physiology of those individuals, although our results support a reproductive priming effect.


Behaviour ◽  
2014 ◽  
Vol 151 (1) ◽  
pp. 47-71 ◽  
Author(s):  
Kristina Hick ◽  
Adam R. Reddon ◽  
Constance M. O’Connor ◽  
Sigal Balshine

The costs and benefits of engaging in a contest will differ depending on the social situation of the individuals involved. Therefore, understanding contest behaviour can help to elucidate the trade-offs of living in differing social systems and shed light on the evolution of social behaviour. In the current study, we compared contest behaviour in two closely related species of Lamprologine cichlid fish. Neolamprologus pulcher and Telmatochromis temporalis are both pair-breeding cichlids, but N. pulcher are highly social, group-living fish, while T. temporalis display no grouping behaviour. To examine how competition varies by species, sex and familiarity, we staged same-sex conspecific contests over a shelter, a resource that is highly valued by both species, where contestants were either familiar or unfamiliar to one another. When we examined tactical and strategic components of these contests, we found that the highly social species had shorter contests and engaged in fewer costly aggressive acts than did the non-social species. Individuals of the highly social species were also more likely to resolve conflicts through the use of submissive displays, while individuals of the non-social species were more likely to flee from conflict. Familiarity increased the use of submissive displays in the highly social species but not in the less social species. Our findings suggest that conflict resolution behaviour and dominance hierarchy formation are fundamentally linked to the evolution of complex social systems.


2021 ◽  
Author(s):  
Olof Leimar ◽  
Redouan Bshary

Social hierarchies can increase reproductive skew in group-living animals. Using game theory we investigate how the opportunity for differently ranked individuals to acquire resources influences reproductive skew, costs of hierarchy formation, and winner and loser effects. Individuals adjust their aggressive and submissive behaviour through reinforcement learning. The learning is based on perceived rewards and penalties, which depend on relative fighting ability. From individual-based simulations we determine evolutionary equilibria of traits that control an individual's learning. We examine situations that differ in the extent of monopolisation of contested resources by dominants and in the amounts of uncontested resources that are distributed independently of rank. With costly fighting, we find that stable dominance hierarchies form, such that reproductive skew mirrors the distribution of resources over ranks. Individuals pay substantial costs of interacting, in particular in high-skew situations, with the highest costs paid by intermediately ranked individuals. For cases where dominants monopolise contested resources there are notable winner and loser effects, with winner effects for high ranks and very pronounced loser effects for lower ranks. The effects are instead weak when acquired resources increase linearly with rank. We compare our results on contest costs and winner-loser effects with field and experimental observations.


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