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 Understanding primate brain evolution

2007 ◽  
Vol 362 (1480) ◽  
pp. 649-658 ◽  
Author(s):  
R.I.M Dunbar ◽  
Susanne Shultz
Keyword(s):  
Life History ◽  
Path Analysis ◽  
Group Size ◽  
Brain Size ◽  
Brain Evolution ◽  
Primate Brain ◽  
The Social ◽  
Large Brain ◽  
Brain Data ◽  
The Relationship

We present a detailed reanalysis of the comparative brain data for primates, and develop a model using path analysis that seeks to present the coevolution of primate brain (neocortex) and sociality within a broader ecological and life-history framework. We show that body size, basal metabolic rate and life history act as constraints on brain evolution and through this influence the coevolution of neocortex size and group size. However, they do not determine either of these variables, which appear to be locked in a tight coevolutionary system. We show that, within primates, this relationship is specific to the neocortex. Nonetheless, there are important constraints on brain evolution; we use path analysis to show that, in order to evolve a large neocortex, a species must first evolve a large brain to support that neocortex and this in turn requires adjustments in diet (to provide the energy needed) and life history (to allow sufficient time both for brain growth and for ‘software’ programming). We review a wider literature demonstrating a tight coevolutionary relationship between brain size and sociality in a range of mammalian taxa, but emphasize that the social brain hypothesis is not about the relationship between brain/neocortex size and group size per se ; rather, it is about social complexity and we adduce evidence to support this. Finally, we consider the wider issue of how mammalian (and primate) brains evolve in order to localize the social effects.

scholarly journals Social environment influences the relationship between genotype and gene expression in wild baboons

2013 ◽  
Vol 368 (1618) ◽  
pp. 20120345 ◽  
Author(s):  
Daniel E. Runcie ◽  
Ralph T. Wiedmann ◽  
Elizabeth A. Archie ◽  
Jeanne Altmann ◽  
Gregory A. Wray ◽  
...  
Keyword(s):  
Gene Expression ◽  
Individual Differences ◽  
Social Environment ◽  
Group Size ◽  
Early Life ◽  
Social Connectedness ◽  
Dominance Rank ◽  
Social Stressors ◽  
The Social ◽  
Wild Baboons

Variation in the social environment can have profound effects on survival and reproduction in wild social mammals. However, we know little about the degree to which these effects are influenced by genetic differences among individuals, and conversely, the degree to which social environmental variation mediates genetic reaction norms. To better understand these relationships, we investigated the potential for dominance rank, social connectedness and group size to modify the effects of genetic variation on gene expression in the wild baboons of the Amboseli basin. We found evidence for a number of gene–environment interactions (GEIs) associated with variation in the social environment, encompassing social environments experienced in adulthood as well as persistent effects of early life social environment. Social connectedness, maternal dominance rank and group size all interacted with genotype to influence gene expression in at least one sex, and either in early life or in adulthood. These results suggest that social and behavioural variation, akin to other factors such as age and sex, can impact the genotype–phenotype relationship. We conclude that GEIs mediated by the social environment are important in the evolution and maintenance of individual differences in wild social mammals, including individual differences in responses to social stressors.

scholarly journals Experience of adults with cystic fibrosis: a perspective based on social phenomenology

2018 ◽  
Vol 71 (6) ◽  
pp. 2891-2898
Author(s):  
Samara Macedo Cordeiro ◽  
Maria Cristina Pinto de Jesus ◽  
Renata Evangelista Tavares ◽  
Deise Moura de Oliveira ◽  
Miriam Aparecida Barbosa Merighi
Keyword(s):  
Cystic Fibrosis ◽  
Life History ◽  
Qualitative Study ◽  
Health Professionals ◽  
Daily Life ◽  
The Social ◽  
The World ◽  
Social Prejudice ◽  
The Relationship ◽  
Social Phenomenology

ABSTRACT Objective: To understand the experience of adults living with cystic fibrosis. Method: A qualitative study based on the social phenomenology by Alfred Schütz, carried out with 12 adults interviewed in 2016. The statements were analyzed and organized into concrete categories. Results: The following categories were evidenced: “The biopsychosocial impact of the disease on daily life”, “Social prejudice as a generator of embarrassment”, “Coping strategies” and “Fear, uncertainties and the desire to carry out life projects”. Final considerations: The understanding of the experience lived by adults with cystic fibrosis allowed unveiling intersubjective aspects experienced by this public that should be considered by health professionals in the care of this group. It is up to the professionals involved in assisting these people to develop care strategies aimed at completeness, respect for the world of meanings of each individual, their life history, and intersubjectivity that is specially built in the relationship between professionals and people with cystic fibrosis.

scholarly journals Why does offspring size affect performance? Integrating metabolic scaling with life-history theory

2015 ◽  
Vol 282 (1819) ◽  
pp. 20151946 ◽  
Author(s):  
Amanda K. Pettersen ◽  
Craig R. White ◽  
Dustin J. Marshall
Keyword(s):  
Life History ◽  
Life History Theory ◽  
Maternal Investment ◽  
Offspring Size ◽  
Metabolic Efficiency ◽  
Metabolic Scaling ◽  
And Performance ◽  
The Relationship ◽  
General Explanation ◽  
Better Than

Within species, larger offspring typically outperform smaller offspring. While the relationship between offspring size and performance is ubiquitous, the cause of this relationship remains elusive. By linking metabolic and life-history theory, we provide a general explanation for why larger offspring perform better than smaller offspring. Using high-throughput respirometry arrays, we link metabolic rate to offspring size in two species of marine bryozoan. We found that metabolism scales allometrically with offspring size in both species: while larger offspring use absolutely more energy than smaller offspring, larger offspring use proportionally less of their maternally derived energy throughout the dependent, non-feeding phase. The increased metabolic efficiency of larger offspring while dependent on maternal investment may explain offspring size effects—larger offspring reach nutritional independence (feed for themselves) with a higher proportion of energy relative to structure than smaller offspring. These findings offer a potentially universal explanation for why larger offspring tend to perform better than smaller offspring but studies on other taxa are needed.

Egg size and taxon: their influence on survival and development of chrysopid hatchlings after food and water deprivation

1991 ◽  
Vol 69 (10) ◽  
pp. 2644-2650 ◽  
Author(s):  
Catherine A. Tauber ◽  
Maurice J. Tauber ◽  
Michael J. Tauber
Keyword(s):  
Life History ◽  
Water Deprivation ◽  
Egg Size ◽  
Maternal Investment ◽  
Developmental Rate ◽  
Life History Variation ◽  
Larval Size ◽  
First Instar ◽  
Survival And Development ◽  
Phylogenetic Lineages

Genus- and species-level differences characterize the pattern of life-history variation in two distinct phylogenetic lineages of chrysopids, Chrysopa and Chrysoperla. Species in the genus Chrysopa exhibit significant variation in egg size, and this variation is positively correlated with the ability of hatchlings to withstand periods of food and water deprivation prior to their initial feeding. The variation is also significantly correlated with larval size, as measured by the tibial length of first-instar larvae. Although the six Chrysopa species differ in several other life-history traits (i.e, the incubation period and rate of first-instar larval development), the variation is unrelated to egg size. It appears that maternal allocation of resources to eggs largely serves to enhance embryonic growth and the survival of hatchlings during searching. That is, within the Chrysopa lineage egg size varies; larger eggs yield larger, more robust hatchlings. These hatchlings may or may not develop faster than congeners from small eggs. In comparison with Chrysopa, the genus Chrysoperla has less variability in egg size and developmental rate. Furthermore, although Chrysoperla eggs are relatively small, the ability of hatchlings to endure periods of food or water deprivation is at least as great as it is in the Chrysopa species with large eggs. We conclude that maternal investment in larval fitness has different ontogenetic pathways, ecological roles, and phylogenetic histories in the two genera.

scholarly journals Effect of mate size on maternal reproductive effort in the convict cichlid Amatitlania siquia

2012 ◽  
Vol 58 (1) ◽  
pp. 66-72 ◽  
Author(s):  
Ashley R. Robart
Keyword(s):  
Parental Care ◽  
Standard Length ◽  
Reproductive Investment ◽  
Differential Allocation ◽  
Mate Quality ◽  
Convict Cichlids ◽  
Male Care ◽  
Female Investment ◽  
The Relationship ◽  
Amatitlania Siquia

Abstract The differential allocation hypothesis predicts individuals will increase their reproductive investment when mated to a high quality partner. In many species of fish with biparental care females prefer large males due to the males’ greater ability to raise more offspring to independence. I examined the relationship between mate quality, parental care and number of offspring in a natural population of convict cichlids Amatitlania siquia. The frequency of frontal displays by females was positively correlated with male standard length. Additionally, as males increased in length relative to their mate, females increased the frequency of chases towards predators, while males decreased the number of displays towards brood predators. This trade-off in parental effort within a pair due to mate quality is a key prediction of differential allocation. The number of offspring was correlated with male, but not female, standard length. These results support the differential allocation hypothesis in that females offered more parental care to offspring of a larger male, while their mates decreased the amount of care they provided. Additionally, females benefited in terms of number of offspring by pairing with higher quality mates. Increased female investment may provide an incentive to ensure male care and maintain pair bonding, which could lead to greater reproductive success through increased offspring survival.

scholarly journals TRADISI NGAJAHUL: Fikih Pemakaman dan Kohesi Sosial Pada Masyarakat Muslim Priangan

2019 ◽  
Vol 14 (1) ◽  
pp. 27
Author(s):  
Yayan Suryana
Keyword(s):  
Social Interaction ◽  
Social Environment ◽  
Social Relations ◽  
Social Cohesion ◽  
Social Life ◽  
Sociological Perspective ◽  
Death Rituals ◽  
The Social ◽  
The Family ◽  
The Relationship

This paper presents an analysis of the death rituals carried out by Muslims in the Priangan region known as ngajahul. Ngajahul is done on the sixth or seventh day after death. Analysis of the ritual of death illustrates that the ritual of death is not only a spiritual-fiqhiyyah aspect, but also has a role in describing social relations. The graveyard that lay in the cemetery, not only shows the grave, but also describes the relationship between the deceased, the family and the social environment. This research in a sociological perspective produces the concept that the rituals of death and society, especially Muslim societies in various aspects are referred to as containing social cohesion. This concept illustrates that death rituals are not as depicted in recitation forums that see death rituals as a tradition laden with rituals that are spiritually nuanced. Ngajahul is a tradition that produces social interaction and involvement in social life that is produced simultaneously. Key Words : Ngajahul, Ritual, Social cohesion, fiqhiyyah

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