scholarly journals Rearing-Group Size Determines Social Competence and Brain Structure in a Cooperatively Breeding Cichlid

2015 ◽  
Vol 186 (1) ◽  
pp. 123-140 ◽  
Author(s):  
Stefan Fischer ◽  
Mathilde Bessert-Nettelbeck ◽  
Alexander Kotrschal ◽  
Barbara Taborsky
Keyword(s):  
Social Competence ◽  
Group Size ◽  
Brain Structure ◽  
Cooperatively Breeding

scholarly journals The relationship between egg size and helper number in cooperative breeders: a meta-analysis across species

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4028 ◽  
Author(s):  
Tanmay Dixit ◽  
Sinead English ◽  
Dieter Lukas
Keyword(s):  
Life History ◽  
Social Environment ◽  
Group Size ◽  
Egg Size ◽  
Reproductive Investment ◽  
Maternal Investment ◽  
Differential Allocation ◽  
The Social ◽  
Cooperatively Breeding ◽  
The Relationship

BackgroundLife history theory predicts that mothers should adjust reproductive investment depending on benefits of current reproduction and costs of reduced future reproductive success. These costs and benefits may in turn depend on the breeding female’s social environment. Cooperative breeders provide an ideal system to test whether changes in maternal investment are associated with the social conditions mothers experience. As alloparental helpers assist in offspring care, larger groups might reduce reproductive costs for mothers or alternatively indicate attractive conditions for reproduction. Thus, mothers may show reduced (load-lightening) or increased (differential allocation) reproductive investment in relation to group size. A growing number of studies have investigated how cooperatively breeding mothers adjust pre-natal investment depending on group size. Our aim was to survey these studies to assess, first, whether mothers consistently reduce or increase pre-natal investment when in larger groups and, second, whether these changes relate to variation in post-natal investment.MethodsWe extracted data on the relationship between helper number and maternal pre-natal investment (egg size) from 12 studies on 10 species of cooperatively breeding vertebrates. We performed meta-analyses to calculate the overall estimated relationship between egg size and helper number, and to quantify variation among species. We also tested whether these relationships are stronger in species in which the addition of helpers is associated with significant changes in maternal and helper post-natal investment.ResultsAcross studies, there is a significant negative relationship between helper number and egg size, suggesting that in most instances mothers show reduced reproductive investment in larger groups, in particular in species in which mothers also show a significant reduction in post-natal investment. However, even in this limited sample, substantial variation exists in the relationship between helper number and egg size, and the overall effect appears to be driven by a few well-studied species.DiscussionOur results, albeit based on a small sample of studies and species, indicate that cooperatively breeding females tend to produce smaller eggs in larger groups. These findings on prenatal investment accord with previous studies showing similar load-lightening reductions in postnatal parental effort (leading to concealed helper effects), but do not provide empirical support for differential allocation. However, the considerable variation in effect size across studies suggests that maternal investment is mitigated by additional factors. Our findings indicate that variation in the social environment may influence life-history strategies and suggest that future studies investigating within-individual changes in maternal investment in cooperative breeders offer a fruitful avenue to study the role of adaptive plasticity.

scholarly journals Natal territory size, group size, and body mass affect lifetime fitness in the cooperatively breeding Florida Scrub-Jay

The Auk ◽  
2015 ◽  
Vol 132 (3) ◽  
pp. 634-646 ◽  
Author(s):  
Ronald L. Mumme ◽  
Reed Bowman ◽  
M. Shane Pruett ◽  
John W. Fitzpatrick
Keyword(s):  
Body Mass ◽  
Group Size ◽  
Size Group ◽  
Territory Size ◽  
Florida Scrub ◽  
Lifetime Fitness ◽  
Cooperatively Breeding

scholarly journals Compensatory and additive helper effects in the cooperatively breeding Seychelles warbler (Acrocephalus sechellensis)

2018 ◽  
Author(s):  
Lotte A. van Boheemen ◽  
Martijn Hammers ◽  
Sjouke A. Kingma ◽  
David S. Richardson ◽  
Terry Burke ◽  
...  
Keyword(s):  
Group Size ◽  
Food Availability ◽  
Dominant Male ◽  
List Type ◽  
Territory Quality ◽  
Trade Offs ◽  
Cooperatively Breeding ◽  
Helping Behaviour ◽  
Seychelles Warbler ◽  
The Impact

ABSTRACTIn cooperatively breeding species, helper aid may affect dominant breeders’ investment trade-offs between current and future reproduction. By compensating for the care provided by helpers, breeders can reduce the costs of reproduction and improve chances of survival. Also, helper care can be additive to that of dominants, resulting in higher success of the current brood.However, the influence of helpers on offspring care itself may be the by-product of group size and territory quality. Therefore to make conclusive inferences about causation of additive and compensatory care as a result of helpper serequires disentangling the impact of helping from other factors determining parental investment.In this study, we use 20 years of offspring provisioning data to investigate the effect of helping on breeder and overall offspring provisioning rates in the facultative cooperatively breeding Seychelles warbler (Acrocephalus sechellensis). Our extensive dataset allowed us to effectively control for the effects of living in a larger group and in territories with higher food availability.We show compensatory and additive care in response to helper aid. Helpers lightened the provisioning load of the dominant male and female and increased the total provisioning to the nestlings. This was irrespective of group size or territory quality (food availability).Our results illustrate how multiple benefits of helping behaviour can simultaneously be fundamental to the evolutionary maintenance of cooperative behaviour.

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

Behaviour ◽  
2005 ◽  
Vol 142 (11-12) ◽  
pp. 1615-1641 ◽  
Author(s):  
Michael Taborsky ◽  
Lyanne Brouwer ◽  
Dik Heg ◽  
Zina Bachar
Keyword(s):  
Group Size ◽  
The Body ◽  
Female Size ◽  
Neolamprologus Pulcher ◽  
Large Group ◽  
Cooperatively Breeding ◽  
Group Members ◽  
One Year ◽  
Large Groups

AbstractGroup size has been shown to positively influence survival of group members in many cooperatively breeding vertebrates, including the Lake Tanganyika cichlid Neolamprologus pulcher, suggesting Allee effects. However, long-term data are scarce to test how these survival differences translate into changes in group extinction risk, group size and composition. We show in a field study of 117 groups from six different colonies (three from two populations each), that group size critically influences these parameters between years. Within one year, 34% of the groups went extinct. Group size correlated positively between years and large groups did not go extinct. The latter were more likely to contain small helpers the subsequent year, which is a cumulative measure of the previous months' reproductive success. Finally, there was a tendency that large groups were more likely to contain a breeding male and female still a year after the first check. The breeder male size, breeder female size, and largest helper size did not influence these parameters, and also did not correlate with the sizes of these categories of fish after one year. This suggests that group size, and not the body size or fighting ability of group members, was the critical variable determining the success of groups. In total, seven groups had fused with other groups between years. To our knowledge, this is the first study showing long-term benefits of large group size in a cooperatively breeding fish. We discuss the importance of differential survival and dispersal of group members for the demonstrated group size effects.

scholarly journals Group-size-dependent punishment of idle subordinates in a cooperative breeder where helpers pay to stay

2014 ◽  
Vol 281 (1789) ◽  
pp. 20140184 ◽  
Author(s):  
Stefan Fischer ◽  
Markus Zöttl ◽  
Frank Groenewoud ◽  
Barbara Taborsky
Keyword(s):  
Group Size ◽  
Small Groups ◽  
Cooperative Breeding ◽  
Breeding Systems ◽  
Idle Period ◽  
Cognitive Constraints ◽  
Size Dependent ◽  
Cooperatively Breeding ◽  
Group Members ◽  
Large Groups

In cooperative breeding systems, dominant breeders sometimes tolerate unrelated individuals even if they inflict costs on the dominants. According to the ‘pay-to-stay’ hypothesis, (i) subordinates can outweigh these costs by providing help and (ii) dominants should be able to enforce help by punishing subordinates that provide insufficient help. This requires that dominants can monitor helping and can recognize group members individually. In a field experiment, we tested whether cooperatively breeding cichlid Neolamprologus pulcher subordinates increase their help after a forced ‘idle’ period, how other group members respond to a previously idle helper, and how helper behaviour and group responses depend on group size. Previously idle helpers increased their submissiveness and received more aggression than control helpers, suggesting that punishment occurred to enforce help. Subordinates in small groups increased their help more than those in large groups, despite receiving less aggression. When subordinates were temporarily removed, dominants in small groups were more likely to evict returning subordinates. Our results suggest that only in small groups do helpers face a latent threat of punishment by breeders as predicted by the pay-to-stay hypothesis. In large groups, cognitive constraints may prevent breeders from tracking the behaviour of a large number of helpers.

Group size and aggression: ‘recruitment incentives’ in a cooperatively breeding primate

1997 ◽  
Vol 54 (1) ◽  
pp. 171-180 ◽  
Author(s):  
COLLEEN M SCHAFFNER ◽  
JEFFREY A FRENCH
Keyword(s):  
Group Size ◽  
Cooperatively Breeding

scholarly journals Sex differences in responsiveness to begging in a cooperative mammal

2008 ◽  
Vol 4 (4) ◽  
pp. 334-337 ◽  
Author(s):  
Sinead English ◽  
Hansjoerg P Kunc ◽  
Joah R Madden ◽  
Tim H Clutton-Brock
Keyword(s):  
Sex Differences ◽  
Parental Care ◽  
Group Size ◽  
Feeding Rate ◽  
Foraging Success ◽  
Sensitive Measure ◽  
Food Items ◽  
Suricata Suricatta ◽  
Cooperatively Breeding ◽  
Consistent Tendency

In species where young are provisioned by both parents, males commonly contribute less to parental care than females, and are less responsive to variation in begging rates. Similar differences in the care of young occur among adults in cooperative breeders, but fewer studies have investigated whether these are associated with differences in responsiveness. Here, we present results from a playback experiment investigating responsiveness to begging in the meerkat ( Suricata suricatta ), a cooperatively breeding mammal. Although increased begging rate raised the feeding rate of adults of both sexes, there was no consistent tendency for females to be more responsive than males. However, when we examined changes in the proportion of food items found that were fed to pups (generosity), we found that females were more responsive than males to increased begging rate. These results can be explained in terms of sex differences in dispersal: in meerkats, females are philopatric and receive considerable benefits from investing in young, both directly, by increasing group size, and indirectly, by recruiting helpers if they inherit the breeding position. In addition, they emphasize that generosity provides a more sensitive measure of responsiveness to begging than feeding rate, as it accounts for variation in foraging success.

Communal roosting, thermoregulatory benefits and breeding group size predictability in cooperatively breeding sociable weavers

2016 ◽  
Vol 47 (6) ◽  
pp. 749-755 ◽  
Author(s):  
Matthieu Paquet ◽  
Claire Doutrelant ◽  
Maxime Loubon ◽  
Franck Theron ◽  
Margaux Rat ◽  
...  
Keyword(s):  
Group Size ◽  
Breeding Group ◽  
Cooperatively Breeding ◽  
Sociable Weavers ◽  
Communal Roosting

Contributions to care vary with age, sex, breeding status and group size in the cooperatively breeding apostlebird

2006 ◽  
Vol 72 (1) ◽  
pp. 63-73 ◽  
Author(s):  
Iain A. Woxvold ◽  
Raoul A. Mulder ◽  
Michael J.L. Magrath
Keyword(s):  
Group Size ◽  
Cooperatively Breeding ◽  
Breeding Status

scholarly journals Reproductive sharing in relation to group and colony-level attributes in a cooperative breeding fish

2015 ◽  
Vol 282 (1811) ◽  
pp. 20150954 ◽  
Author(s):  
Jennifer K. Hellmann ◽  
Isaac Y. Ligocki ◽  
Constance M. O'Connor ◽  
Adam R. Reddon ◽  
Kelly A. Garvy ◽  
...  
Keyword(s):  
Group Size ◽  
Spatial Scales ◽  
Model Species ◽  
Cooperatively Breeding ◽  
Group Members ◽  
Males And Females ◽  
Territory Density ◽  
Large Groups ◽  
Colony Level ◽  
Group Size And Composition

The degree to which group members share reproduction is dictated by both within-group (e.g. group size and composition) and between-group (e.g. density and position of neighbours) characteristics. While many studies have investigated reproductive patterns within social groups, few have simultaneously explored how within-group and between-group social structure influence these patterns. Here, we investigated how group size and composition, along with territory density and location within the colony, influenced parentage in 36 wild groups of a colonial, cooperatively breeding fish Neolamprologus pulcher . Dominant males sired 76% of offspring in their group, whereas dominant females mothered 82% of offspring in their group. Subordinate reproduction was frequent, occurring in 47% of sampled groups. Subordinate males gained more paternity in groups located in high-density areas and in groups with many subordinate males. Dominant males and females in large groups and in groups with many reproductively mature subordinates had higher rates of parentage loss, but only at the colony edge. Our study provides, to our knowledge, the first comprehensive quantification of reproductive sharing among groups of wild N. pulcher , a model species for the study of cooperation and social behaviour. Further, we demonstrate that the frequency of extra-pair parentage differs across small social and spatial scales.

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