scholarly journals No evidence for larger brains in cooperatively breeding cichlid fishes

2016 ◽  
Vol 94 (5) ◽  
pp. 373-378 ◽  
Author(s):  
Adam R. Reddon ◽  
Constance M. O’Connor ◽  
Isaac Y. Ligocki ◽  
Jennifer K. Hellmann ◽  
Susan E. Marsh-Rollo ◽  
...  

The social brain hypothesis posits that frequent social interactions, characteristic of group living species, select for greater socio-cognitive abilities and the requisite neural machinery. An extension of the social brains hypothesis, known as the cooperative breeding brain hypothesis, postulates that cooperatively breeding species, which live in stable social groups and provide allocare, face particularly pronounced cognitive demands because they must recognize, remember, and differentially respond to multiple group members. These socio-cognitive challenges are thought to have selected for increased cognitive capacity, supported by a bigger brain. To test the prediction that cooperative breeders have larger brains, we performed a phylogenetically controlled comparison of the whole brain masses of adult fish from 16 closely related species of cooperatively and independently breeding lamprologine cichlid species from Lake Tanganyika. We collected data on brain mass from males of eight species of lamprologine cichlids and added this to brain mass data from eight more species found in the published literature. Controlling for body size and phylogeny, we found that cooperative breeding species did not have larger brains, and this was true of for both our field-collected data set and the expanded data set including published values. This study adds to a growing body of literature from other taxa that cast doubt on the cooperative breeding brain hypothesis.

Behaviour ◽  
2019 ◽  
Vol 156 (5-8) ◽  
pp. 721-761
Author(s):  
Anastasia Krasheninnikova ◽  
Roberta Berardi ◽  
Mari-Ann Lind ◽  
Laurie O’Neill ◽  
Auguste M.P. von Bayern

AbstractSystematic, broad phylogenetic comparisons of diverse cognitive abilities are essential to understand cognitive evolution. Few studies have examined multiple skills comparatively, using identical tasks across species. Previous research centered on primates, but recent evidence suggests that complex cognition may have evolved in distantly related taxa. We administered the tasks of the primate cognition test battery (PCTB) to 4 parrot species for a first direct comparison with primates. The parrots did not perform significantly worse than the previously tested primates in all but one of the test scales, but remained at chance levels throughout. Chimpanzees outperformed them in the physical but not the social domain. No differences between the domains nor across the parrot species were detected. It remains questionable whether the chance level performance reflects the parrots’ cognitive capacity or results from task constraints, which would limit the suitability of PCTB for phylogenetic comparisons. Possible implications for the field are discussed.


2018 ◽  
Vol 373 (1756) ◽  
pp. 20170288 ◽  
Author(s):  
Benjamin J. Ashton ◽  
Alex Thornton ◽  
Amanda R. Ridley

The prevailing hypotheses for the evolution of cognition focus on either the demands associated with group living (the social intelligence hypothesis (SIH)) or ecological challenges such as finding food. Comparative studies testing these hypotheses have generated highly conflicting results; consequently, our understanding of the drivers of cognitive evolution remains limited. To understand how selection shapes cognition, research must incorporate an intraspecific approach, focusing on the causes and consequences of individual variation in cognition. Here, we review the findings of recent intraspecific cognitive research to investigate the predictions of the SIH. Extensive evidence from our own research on Australian magpies ( Cracticus tibicen dorsalis ), and a number of other taxa, suggests that individuals in larger social groups exhibit elevated cognitive performance and, in some cases, elevated reproductive fitness. Not only do these findings demonstrate how the social environment has the potential to shape cognitive evolution, but crucially, they demonstrate the importance of considering both genetic and developmental factors when attempting to explain the causes of cognitive variation. This article is part of the theme issue ‘Causes and consequences of individual differences in cognitive abilities’.


Behaviour ◽  
2015 ◽  
Vol 152 (12-13) ◽  
pp. 1821-1839 ◽  
Author(s):  
Isaac Y. Ligocki ◽  
Adam R. Reddon ◽  
Jennifer K. Hellmann ◽  
Constance M. O’Connor ◽  
Susan Marsh-Rollo ◽  
...  

In group living animals, individuals may visit other groups. The costs and benefits of such visits for the members of a group will depend on the attributes and intentions of the visitor, and the social status of responding group members. Using wild groups of the cooperatively breeding cichlid fish (Neolamprologus pulcher), we compared group member responses to unfamiliar ‘visiting’ conspecifics in control groups and in experimentally manipulated groups from which a subordinate the same size and sex as the visitor was removed. High-ranking fish were less aggressive towards visitors in removal groups than in control groups; low-ranking subordinates were more aggressive in the removal treatment. High-ranking females and subordinates the same size and sex as the visitor responded most aggressively toward the visitor in control groups. These results suggest that visitors are perceived as potential group joiners, and that such visits impose different costs and benefits on current group members.


2018 ◽  
Vol 285 (1882) ◽  
pp. 20181017 ◽  
Author(s):  
Michael A. Pardo ◽  
Emilee A. Sparks ◽  
Tejal S. Kuray ◽  
Natasha D. Hagemeyer ◽  
Eric L. Walters ◽  
...  

According to the social intelligence hypothesis, understanding the cognitive demands of the social environment is key to understanding the evolution of intelligence. Many important socio-cognitive abilities, however, have primarily been studied in a narrow subset of the social environment—within-group social interactions—despite the fact that between-group social interactions often have a substantial effect on fitness. In particular, triadic awareness (knowledge about the relationships and associations between others) is critical for navigating many types of complex social interactions, yet no existing study has investigated whether wild animals can track associations between members of other social groups. We investigated inter-group triadic awareness in wild acorn woodpeckers ( Melanerpes formicivorus ), a socially complex group-living bird. We presented woodpeckers with socially incongruous playbacks that simulated two outsiders from different groups calling together, and socially congruous playbacks that simulated two outsiders from the same group calling together. Subjects responded more quickly to the incongruous playbacks, suggesting that they were aware that the callers belonged to two different groups. This study provides the first demonstration that animals can recognize associations between members of other groups under natural circumstances, and highlights the importance of considering how inter-group social selection pressures may influence the evolution of cognition.


Behaviour ◽  
2019 ◽  
Vol 156 (5-8) ◽  
pp. 721-761 ◽  
Author(s):  
Anastasia Krasheninnikova ◽  
Roberta Berardi ◽  
Mari-Ann Lind ◽  
Laurie O’Neill ◽  
Auguste M.P. von Bayern

Abstract Systematic, broad phylogenetic comparisons of diverse cognitive abilities are essential to understand cognitive evolution. Few studies have examined multiple skills comparatively, using identical tasks across species. Previous research centered on primates, but recent evidence suggests that complex cognition may have evolved in distantly related taxa. We administered the tasks of the primate cognition test battery (PCTB) to 4 parrot species for a first direct comparison with primates. The parrots did not perform significantly worse than the previously tested primates in all but one of the test scales, but remained at chance levels throughout. Chimpanzees outperformed them in the physical but not the social domain. No differences between the domains nor across the parrot species were detected. It remains questionable whether the chance level performance reflects the parrots’ cognitive capacity or results from task constraints, which would limit the suitability of PCTB for phylogenetic comparisons. Possible implications for the field are discussed.


2017 ◽  
Vol 4 (5) ◽  
pp. 170350 ◽  
Author(s):  
Adam R. Reddon ◽  
Constance M. O'Connor ◽  
Erin Nesjan ◽  
Jason Cameron ◽  
Jennifer K. Hellmann ◽  
...  

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.


2016 ◽  
Vol 371 (1687) ◽  
pp. 20150097 ◽  
Author(s):  
Joan B. Silk ◽  
Bailey R. House

In this paper, we consider three hypotheses to account for the evolution of the extraordinary capacity for large-scale cooperation and altruistic social preferences within human societies. One hypothesis is that human cooperation is built on the same evolutionary foundations as cooperation in other animal societies, and that fundamental elements of the social preferences that shape our species' cooperative behaviour are also shared with other closely related primates. Another hypothesis is that selective pressures favouring cooperative breeding have shaped the capacity for cooperation and the development of social preferences, and produced a common set of behavioural dispositions and social preferences in cooperatively breeding primates and humans. The third hypothesis is that humans have evolved derived capacities for collaboration, group-level cooperation and altruistic social preferences that are linked to our capacity for culture. We draw on naturalistic data to assess differences in the form, scope and scale of cooperation between humans and other primates, experimental data to evaluate the nature of social preferences across primate species, and comparative analyses to evaluate the evolutionary origins of cooperative breeding and related forms of behaviour.


The Auk ◽  
2003 ◽  
Vol 120 (3) ◽  
pp. 717-729
Author(s):  
Rebecca T. Kimball ◽  
Patricia G. Parker ◽  
James C. Bednarz

Abstract Cooperative breeding, in which more than two individuals live in a group and raise offspring, usually in a single nest, is found in only 3% of avian species. On the basis of a review of the literature, we found reports of groups (usually trios) at nest sites in 42 species of diurnal raptors. At least one example of cooperative breeding was found in 29% of genera and 14% of species, distributed in both Accipitridae and Falconidae. Given the difficulty of obtaining behavioral observations necessary to detect cooperative breeding in most raptor species, combined with the large number of species that have been poorly studied, cooperative breeding in diurnal raptors may be more common than our data indicate. However, when data on the sex of the extra bird(s) or relationships among group members were available, patterns were quite varied. For 7 of 13 species, groups primarily contained multiple adult males, though three of those species also had groups formed from offspring that had delayed dispersal; three species had a low, but regular, occurrence of multiple females (females of groups laid eggs in the same nest); and the remaining three species were characterized by having extra birds that were yearlings or subadults. In over half of species, groups did not appear to be composed of related individuals, contrary to many cooperatively breeding passerine species where groups are primarily composed of offspring that have delayed dispersal. Our review suggests that the evolution of group living in many raptors may be independent of delayed dispersal, and that the factors important in explaining the evolution of that behavior depend upon the benefits of group living.


2020 ◽  
Author(s):  
Claudia A.F. Wascher

AbstractThe social environment strongly affects the physiological stress response in group living animals, which in turn can affect the immune system and increase susceptibility to parasites. Here, I investigate relationships between social behavior and gastrointestinal parasite product excretion in the carrion crow (Corvus corone). Individuals from a population of non-cooperatively breeding carrion crows excreted less samples containing coccidian oocysts when kept in larger groups (8 or 9 individuals) compared to those individuals kept in smaller groups (2 or 3 individuals). Lower-ranking individuals excreted more samples containing parasite oocysts compared to higher-ranking individuals. The strength of affiliative relationships and number of related individuals in the group did not relate to the proportion of droppings containing coccidian oocysts. The present results confirm an association between social environment and parasite excretion patterns in carrion crows, but the patterns described in the present study differ from previously published data derived from a group of cooperatively breeding crows. This illustrates that differences between the social systems of carrion crows might result in different associations between the social environment and parasite product excretion patterns.Significance statementOne major cost of group living is an increase in susceptibility to parasites, however not all group living animals are affected by this in the same way. A better understanding how social behavior is associated with parasite burden can help to better understand evolution of group living. This study attempts to investigate associations between dominance rank, affiliative relationships as well as groups size and gastrointestinal parasite product excretion in a group of captive carrion crows. Lower-ranking individuals excreted more samples containing parasite oocysts compared to higher-ranking individuals, confirming an association between social relationships within the groups (for example dominance rank) and parasite excretion patterns.


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