scholarly journals The oxidative costs of reproduction are group-size dependent in a wild cooperative breeder

2015 ◽  
Vol 282 (1819) ◽  
pp. 20152031 ◽  
Author(s):  
Dominic L. Cram ◽  
Jonathan D. Blount ◽  
Andrew J. Young
Keyword(s):  
Experimental Evidence ◽  
Body Mass ◽  
Group Size ◽  
Life History Theory ◽  
Reproductive Investment ◽  
Costs Of Reproduction ◽  
Breeding Bird ◽  
Reduced Body ◽  
Cooperatively Breeding ◽  
In The Wild

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 hypothesized 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.

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 Hot droughts compromise interannual survival across all group sizes in a cooperatively breeding bird

2020 ◽  
Author(s):  
Amanda R. Bourne ◽  
Susan J. Cunningham ◽  
Claire N. Spottiswoode ◽  
Amanda R. Ridley
Keyword(s):  
Climate Change ◽  
Group Size ◽  
Climatic Conditions ◽  
Breeding Bird ◽  
Body Mass Change ◽  
Species Vulnerability ◽  
Animal Populations ◽  
Cooperatively Breeding ◽  
Dry Conditions ◽  
The Impact

AbstractIncreasingly harsh and unpredictable climate regimes are affecting animal populations around the world as climate change advances. One relatively unexplored aspect of species vulnerability to climate change is whether and to what extent responses to environmental stressors might be mitigated by variation in group size in social species. We used a 15-year dataset for a cooperatively-breeding bird, the southern pied babbler Turdoides bicolor, to determine the impact of temperature, rainfall, and group size on body mass change and interannual survival in both juveniles and adults. Hot and dry conditions were associated with reduced juvenile growth, mass loss in adults, and compromised survival between years in both juveniles (−86%) and adults (−60%). Individuals across all group sizes experienced similar effects of climatic conditions. Larger group sizes may not buffer individual group members against the impacts of hot and dry conditions, which are expected to increase in frequency and severity in future.

scholarly journals Experimental evidence that chronic outgroup conflict reduces reproductive success in a cooperatively breeding fish

2021 ◽  
Author(s):  
Ines Braga Goncalves ◽  
Andy Radford
Keyword(s):  
Reproductive Success ◽  
Experimental Evidence ◽  
Social Evolution ◽  
Group Living ◽  
Reproductive Investment ◽  
Empirical Literature ◽  
Control Groups ◽  
Cooperatively Breeding ◽  
Consistent Group ◽  
Defence Behaviour

Conflicts with conspecific outsiders are common in group-living species, from ants to primates, and are argued to be an important selective force in social evolution. However, whilst an extensive empirical literature exists on the behaviour exhibited during and immediately after interactions with rivals, only very few observational studies have considered the cumulative fitness consequences of outgroup conflict. Using a cooperatively breeding fish, the daffodil cichlid (Neolamprologus pulcher), we conducted the first experimental test of the effects of chronic outgroup conflict on reproductive investment and output. ‘Intruded’ groups received long-term simulated territorial intrusions by neighbours that generated consistent group-defence behaviour; matched ‘Control’ groups (each the same size and with the same neighbours as an Intruded group) received no intrusions in the same period. Intruded groups had longer inter-clutch intervals and produced eggs with less protein than Control groups. Despite this lower egg investment, Intruded groups provided more parental care, achieving similar hatching success to Control groups. Ultimately, however, Intruded groups had fewer and smaller surviving offspring than Control groups at 1-month post-hatching. We therefore provide experimental evidence that outgroup conflict can decrease fitness via cumulative effects on reproductive success, confirming the selective potential of this empirically neglected aspect of sociality.

scholarly journals Variable fledging age according to group size: trade-offs in a cooperatively breeding bird

2007 ◽  
Vol 3 (6) ◽  
pp. 624-627 ◽  
Author(s):  
N.J Raihani ◽  
A.R Ridley
Keyword(s):  
Group Size ◽  
Group Living ◽  
Breeding Bird ◽  
Communal Roost ◽  
Trade Offs ◽  
Efficient Detection ◽  
Risk Of Predation ◽  
Cooperatively Breeding ◽  
Individual Survival ◽  
Dilution Effects

Group living can provide individuals with several benefits, including cooperative vigilance and lower predation rates. Individuals in larger groups may be less vulnerable to predation due to dilution effects, efficient detection or greater ability to repel predators. Individuals in smaller groups may consequently employ alternative behavioural tactics to compensate for their greater vulnerability to predators. Here, we describe how pied babbler ( Turdoides bicolor ) fledging age varies with group size and the associated risk of nestling predation. Nestling predation is highest in smaller groups, but there is no effect of group size on fledgling predation. Consequently, small groups fledge young earlier, thereby reducing the risk of predation. However, there is a cost to this behaviour as younger fledglings are less mobile than older fledglings: they move shorter distances and are less likely to successfully reach the communal roost tree. The optimal age to fledge young appears to depend on the trade-off between reduced nestling predation and increased fledgling mobility. We suggest that such trade-offs may be common in species where group size critically affects individual survival and reproductive success.

scholarly journals Group-foraging is not associated with longevity in North American birds

2009 ◽  
Vol 6 (1) ◽  
pp. 42-44 ◽  
Author(s):  
Guy Beauchamp
Keyword(s):  
Body Mass ◽  
Group Size ◽  
North American ◽  
Life History Theory ◽  
Foraging Efficiency ◽  
Passerine Birds ◽  
Group Foraging ◽  
Evolutionary Transitions ◽  
Age At First Reproduction ◽  
First Reproduction

Group-foraging is common in many animal taxa and is thought to offer protection against predators and greater foraging efficiency. Such benefits may have driven evolutionary transitions from solitary to group-foraging. Greater protection against predators and greater access to resources should reduce extrinsic sources of mortality and thus select for higher longevity according to life-history theory. I assessed the association between group-foraging and longevity in a sample of 421 North American birds. Taking into account known correlates of longevity, such as age at first reproduction and body mass, foraging group size was not correlated with maximum longevity, with and without phylogenetic correction. However, longevity increased with body mass in non-passerine birds. The results suggest that the hypothesized changes in predation risk with group size may not correlate with mortality rate in foraging birds.

scholarly journals Contrasting associations between nestling telomere length and pre and postnatal helpers’ presence in a cooperatively breeding bird

Oecologia ◽  
2021 ◽  
Author(s):  
Martin Quque ◽  
Matthieu Paquet ◽  
Sandrine Zahn ◽  
Frank Théron ◽  
Bruno Faivre ◽  
...  
Keyword(s):  
Telomere Length ◽  
Breeding Bird ◽  
Cooperatively Breeding

scholarly journals Group size and aquatic vegetation modulates male preferences for female shoals in wild zebrafish, Danio rerio

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aditya Ghoshal ◽  
Anuradha Bhat
Keyword(s):  
Group Size ◽  
Aquatic Vegetation ◽  
Natural Habitat ◽  
Ecological Factors ◽  
Choice Test ◽  
Female Group ◽  
Aquatic Flora ◽  
In The Wild ◽  
The Individual

AbstractShoaling decisions in the wild are determined by a combination of innate preferences of the individual along with the interplay of multiple ecological factors. In their natural habitat as well as in the laboratory, zebrafish is a shoaling fish. Here, we investigate the role of group size and associated vegetation in shaping shoaling preferences of wild male zebrafish. We studied the association preference of males to groups of female shoals in a multi-choice test design. We found that males made greater proportion of visits to an 8-female group compared to 2 and 4-female groups. However, males spent similar proportions of time across the three female-containing groups. When artificial vegetation was incorporated along with female number as an additional factor, we found that males prefer high and moderately vegetated patches compared to low or no-vegetation groups, irrespective of the number of females in these patches. Based on experiments using a novel multi-choice design, our results show that preference for group size can change due to interaction of two separate factors. This work is a first attempt to understand the role of aquatic flora in determining shoaling preferences in zebrafish, using an experimental paradigm consisting of a gradation in female and vegetation densities.

Female helpers signal their contribution to chick provisioning in a cooperatively breeding bird

2021 ◽  
Vol 172 ◽  
pp. 113-120
Author(s):  
Eva Trapote ◽  
Daniela Canestrari ◽  
Vittorio Baglione
Keyword(s):  
Breeding Bird ◽  
Cooperatively Breeding
Sign in / Sign up

Export Citation Format

Share Document