scholarly journals Predation risk drives social complexity in cooperative breeders

2016 ◽  
Vol 113 (15) ◽  
pp. 4104-4109 ◽  
Author(s):  
Frank Groenewoud ◽  
Joachim Gerhard Frommen ◽  
Dario Josi ◽  
Hirokazu Tanaka ◽  
Arne Jungwirth ◽  
...  
Keyword(s):  
Social Organization ◽  
Predation Risk ◽  
Social Evolution ◽  
Social Complexity ◽  
Group Structure ◽  
Cichlid Fish ◽  
Group Living ◽  
Ecological Factors ◽  
Habitat Saturation ◽  
Shelter Construction

Predation risk is a major ecological factor selecting for group living. It is largely ignored, however, as an evolutionary driver of social complexity and cooperative breeding, which is attributed mainly to a combination of habitat saturation and enhanced relatedness levels. Social cichlids neither suffer from habitat saturation, nor are their groups composed primarily of relatives. This demands alternative ecological explanations for the evolution of advanced social organization. To address this question, we compared the ecology of eight populations of Neolamprologus pulcher, a cichlid fish arguably representing the pinnacle of social evolution in poikilothermic vertebrates. Results show that variation in social organization and behavior of these fish is primarily explained by predation risk and related ecological factors. Remarkably, ecology affects group structure more strongly than group size, with predation inversely affecting small and large group members. High predation and shelter limitation leads to groups containing few small but many large members, which is an effect enhanced at low population densities. Apparently, enhanced safety from predators by cooperative defense and shelter construction are the primary benefits of sociality. This finding suggests that predation risk can be fundamental for the transition toward complex social organization, which is generally undervalued.

scholarly journals Isotocin neuronal phenotypes differ among social systems in cichlid fishes

2017 ◽  
Vol 4 (5) ◽  
pp. 170350 ◽  
Author(s):  
Adam R. Reddon ◽  
Constance M. O'Connor ◽  
Erin Nesjan ◽  
Jason Cameron ◽  
Jennifer K. Hellmann ◽  
...  
Keyword(s):  
Cooperative Breeding ◽  
Social Evolution ◽  
Social Systems ◽  
Cichlid Fish ◽  
Group Living ◽  
Evolutionary Transition ◽  
Evolution Of Sociality ◽  
Cooperatively Breeding ◽  
Open Question ◽  
Complementary Analysis

Social living has evolved numerous times across a diverse array of animal taxa. An open question is how the transition to a social lifestyle has shaped, and been shaped by, the underlying neurohormonal machinery of social behaviour. The nonapeptide neurohormones, implicated in the regulation of social behaviours, are prime candidates for the neuroendocrine substrates of social evolution. Here, we examined the brains of eight cichlid fish species with divergent social systems, comparing the number and size of preoptic neurons that express the nonapeptides isotocin and vasotocin. While controlling for the influence of phylogeny and body size, we found that the highly social cooperatively breeding species ( n  = 4) had fewer parvocellular isotocin neurons than the less social independently breeding species ( n  = 4), suggesting that the evolutionary transition to group living and cooperative breeding was associated with a reduction in the number of these neurons. In a complementary analysis, we found that the size and number of isotocin neurons significantly differentiated the cooperatively breeding from the independently breeding species. Our results suggest that isotocin is related to sociality in cichlids and may provide a mechanistic substrate for the evolution of sociality.

scholarly journals Social deprivation affects cooperative predator inspection in a cichlid fish

2015 ◽  
Vol 2 (3) ◽  
pp. 140451 ◽  
Author(s):  
Saskia Hesse ◽  
Jaime M. Anaya-Rojas ◽  
Joachim G. Frommen ◽  
Timo Thünken
Keyword(s):  
Social Skills ◽  
Predation Risk ◽  
Social Environment ◽  
Social Deprivation ◽  
Cichlid Fish ◽  
Group Living ◽  
Social Environments ◽  
Complex Behaviour ◽  
Predator Inspection ◽  
The Individual

The social environment individuals are exposed to during ontogeny shapes social skills and social competence in group-living animals. Consequently, social deprivation has serious effects on behaviour and development in animals but little is known about its impact on cooperation. In this study, we examined the effect of social environment on cooperative predator inspection. Predator inspection behaviour is a complex behaviour, which is present in a variety of shoaling fish species. Often, two fish leave the safety of the group and inspect a potentially dangerous predator in order to gather information about the current predation risk. As predator inspection is highly risky, it is prone to conflicts and cheating. However, cooperation among individuals may reduce the individual predation risk. We investigated this complex social behaviour in juveniles of the cichlid fish Pelvicachromis taeniatus that were reared in two different social environments throughout development. Fish reared in a group inspected more often than isolation-reared fish and were more likely to cooperate, i.e. they conducted conjoint inspection of a predator. By contrast, isolation-reared fish were more likely to perform a single inspection without a companion. These results suggest an impairment of cooperative behaviour in isolation-reared fish most probably due to lack of social experience and resulting in lowered social skills needed in coordinated behaviour.

New research frameworks in the study of chimpanzee and gorilla sociality and communication

2019 ◽  
Author(s):  
Sam G. B. Roberts ◽  
Anna Roberts
Keyword(s):  
Social Evolution ◽  
Social Complexity ◽  
Brain Size ◽  
Social Systems ◽  
Strongly Correlated ◽  
The Social ◽  
Human Social Evolution ◽  
Research Frameworks ◽  
New Research ◽  
Large Groups

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

Social ethology of the wolverine

2018 ◽  
Author(s):  
Jeffrey P. Copeland ◽  
Arild Landa ◽  
Kimberly Heinemeyer ◽  
Keith B. Aubry ◽  
Jiska van Dijk ◽  
...  
Keyword(s):  
Social Organization ◽  
Social Interactions ◽  
Resource Availability ◽  
Social Behaviour ◽  
Social System ◽  
Group Living ◽  
Field Studies ◽  
Ecological Framework ◽  
The Social ◽  
Living Species

Social behaviour in solitary carnivores has long been an active area of investigation but for many species remains largely founded in conjecture compared to our understanding of sociality in group-living species. The social organization of the wolverine has, until now, received little attention beyond its portrayal as a typical mustelid social system. In this chapter the authors compile observations of social interactions from multiple wolverine field studies, which are integrated into an ecological framework. An ethological model for the wolverine is proposed that reveals an intricate social organization, which is driven by variable resource availability within extremely large territories and supports social behaviour that underpins offspring development.

“The Real Nature and Spirit of Our Lives”

2018 ◽  
Author(s):  
Amanda Porterfield
Keyword(s):  
Economic Growth ◽  
African Americans ◽  
Social Organization ◽  
Labor Unions ◽  
Social Evolution ◽  
Fourteenth Amendment ◽  
The Real ◽  
Real Nature ◽  
Republican Liberty ◽  
The U.S

Proponents of social evolution blurred boundaries between commerce and Christianity after the Civil War, championing Christian work as a means to economic growth, republican liberty, and national prosperity. Meanwhile, workers invoked Christ to condemn patronizing attitudes toward labor, and by organizing labor unions to hold capitalists accountable to Pauline ideals of social membership. Influenced by organic theories of social organization that traced modern corporations to medieval institutions, U.S. courts began recognizing corporations as natural persons protected by rights guaranteed in the Fourteenth Amendment of the U.S. Constitution, which had originally be crafted to protect the rights of African Americans.

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

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

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

scholarly journals Family feud: permanent group splitting in a highly philopatric mammal, the killer whale (Orcinus orca)

2021 ◽  
Vol 75 (3) ◽  
Author(s):  
Eva H. Stredulinsky ◽  
Chris T. Darimont ◽  
Lance Barrett-Lennard ◽  
Graeme M. Ellis ◽  
John K. B. Ford
Keyword(s):  
Killer Whale ◽  
Group Structure ◽  
Group Living ◽  
Orcinus Orca ◽  
Learning Approaches ◽  
Killer Whales ◽  
Internal Factors ◽  
Individual Fitness ◽  
Leadership Experience

Abstract For animals that tend to remain with their natal group rather than individually disperse, group sizes may become too large to benefit individual fitness. In such cases, group splitting (or fission) allows philopatric animals to form more optimal group sizes without sacrificing all familiar social relationships. Although permanent group splitting is observed in many mammals, it occurs relatively infrequently. Here, we use combined generalized modeling and machine learning approaches to provide a comprehensive examination of group splitting in a population of killer whales (Orcinus orca) that occurred over three decades. Fission occurred both along and across maternal lines, where animals dispersed in parallel with their closest maternal kin. Group splitting was more common: (1) in larger natal groups, (2) when the common maternal ancestor was no longer alive, and (3) among groups with greater substructuring. The death of a matriarch did not appear to immediately trigger splitting. Our data suggest intragroup competition for food, leadership experience and kinship are important factors that influence group splitting in this population. Our approach provides a foundation for future studies to examine the dynamics and consequences of matrilineal fission in killer whales and other taxa. Significance statement Group living among mammals often involves long-term social affiliation, strengthened by kinship and cooperative behaviours. As such, changes in group membership may have significant consequences for individuals’ fitness and a population’s genetic structure. Permanent group splitting is a complex and relatively rare phenomenon that has yet to be examined in detail in killer whales. In the context of a growing population, in which offspring of both sexes remain with their mothers for life, we provide the first in-depth examination of group splitting in killer whales, where splitting occurs both along and across maternal lines. We also undertake the first comprehensive assessment of how killer whale intragroup cohesion is influenced by both external and internal factors, including group structure, population and group demography, and resource abundance.

Plastic territoriality in group-living chestnut-crowned babblers: roles of resource value, holding potential and predation risk

2015 ◽  
Vol 101 ◽  
pp. 155-168 ◽  
Author(s):  
Enrico Sorato ◽  
Philippa R. Gullett ◽  
Matthew J.S. Creasey ◽  
Simon C. Griffith ◽  
Andrew F. Russell
Keyword(s):  
Predation Risk ◽  
Group Living ◽  
Resource Value

scholarly journals A test of male infanticide as a reproductive tactic in a cichlid fish

2017 ◽  
Vol 4 (3) ◽  
pp. 160891 ◽  
Author(s):  
Shagun Jindal ◽  
Aneesh P. H. Bose ◽  
Constance M. O'Connor ◽  
Sigal Balshine
Keyword(s):  
Cichlid Fish ◽  
Group Living ◽  
Laboratory Setting ◽  
Dominant Position ◽  
Egg Cannibalism ◽  
Cooperatively Breeding ◽  
Dominant Individual ◽  
Living Species ◽  
Reproductive Tactic ◽  
Relative Body Size

Infanticide and offspring cannibalism are taxonomically widespread phenomena. In some group-living species, a new dominant individual taking over a group can benefit from infanticide if doing so induces potential mates to become reproductively available sooner. Despite widespread observations of infanticide (i.e. egg cannibalism) among fishes, no study has investigated whether egg cannibalism occurs in fishes as a result of group takeovers, or how this type of cannibalism might be adaptive. Using the cooperatively breeding cichlid, Neolamprologus pulcher , we tested whether new unrelated males entering the dominant position in a social group were more likely to cannibalize eggs, and whether such cannibalism would shorten the interval until the female's next spawning. Females spawned again sooner if their broods were removed than if they were cared for. Egg cannibalism occurred frequently after a group takeover event, and was rarer if the original male remained with the group. While dominant breeder females were initially highly aggressive towards newcomer males that took over the group, the degree of resistance depended on relative body size differences between the new pair and, ultimately, female aggression did not prevent egg cannibalism. Egg cannibalism, however, did not shorten the duration until subsequent spawning, or increase fecundity during subsequent breeding in our laboratory setting. Our results show that infanticide as mediated through group takeovers is a taxonomically widespread behaviour.

Sign in / Sign up

Export Citation Format

Share Document