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Social genetic and social environment effects on parental and helper care in a cooperatively breeding bird.

Adams MJ, Robinson MR, Mannarelli ME, Hatchwell BJ - Proc. Biol. Sci. (2015)

Bottom Line: Controlling for other effects, individuals were consistent in their provisioning effort at a given nest, but adjusted their effort based on who was in their social group, indicating the presence of social effects.However, these social effects differed between years and social contexts, indicating a current environment effect, rather than indicating a genetic or permanent environment effect.While this study reveals the importance of examining environmental and genetic sources of social effects, the framework we present is entirely general, enabling a greater understanding of potentially important social effects within any ecological population.

View Article: PubMed Central - PubMed

Affiliation: Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK m@differentialist.info.

ABSTRACT
Phenotypes expressed in a social context are not only a function of the individual, but can also be shaped by the phenotypes of social partners. These social effects may play a major role in the evolution of cooperative breeding if social partners differ in the quality of care they provide and if individual carers adjust their effort in relation to that of other carers. When applying social effects models to wild study systems, it is also important to explore sources of individual plasticity that could masquerade as social effects. We studied offspring provisioning rates of parents and helpers in a wild population of long-tailed tits Aegithalos caudatus using a quantitative genetic framework to identify these social effects and partition them into genetic, permanent environment and current environment components. Controlling for other effects, individuals were consistent in their provisioning effort at a given nest, but adjusted their effort based on who was in their social group, indicating the presence of social effects. However, these social effects differed between years and social contexts, indicating a current environment effect, rather than indicating a genetic or permanent environment effect. While this study reveals the importance of examining environmental and genetic sources of social effects, the framework we present is entirely general, enabling a greater understanding of potentially important social effects within any ecological population.

No MeSH data available.


Related in: MedlinePlus

Effect sizes. Variance proportions for fixed and random effects predictors relative to observed phenotypic variance VP. Point estimates are surrounded by 50% (heavy lines) and 80% (thin lines) confidence intervals calculated from parametric bootstrapping. Model 1A fit to parent phenotype; model 2A fit to parent and helper phenotype. Models 1A and 2A include only direct effects; models 1B and 2B add social effect of partner identity; models 1C and 2C split social effect into permanent environment and current environment; models 1D and 2D fit social genetic effects. Variance components: A, additive genetic; CE, current environment; PE, permanent environment; N, shared nest environment; ID, social partner identity. H and S subscripts denote social effects from helpers or all breed group members, respectively. Variance attributable to social effects were obtained by multiplying fitted variances by average number of social partners. ΔAIC gives difference between model fit and that of the best model and w gives the AIC weight.
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RSPB20150689F2: Effect sizes. Variance proportions for fixed and random effects predictors relative to observed phenotypic variance VP. Point estimates are surrounded by 50% (heavy lines) and 80% (thin lines) confidence intervals calculated from parametric bootstrapping. Model 1A fit to parent phenotype; model 2A fit to parent and helper phenotype. Models 1A and 2A include only direct effects; models 1B and 2B add social effect of partner identity; models 1C and 2C split social effect into permanent environment and current environment; models 1D and 2D fit social genetic effects. Variance components: A, additive genetic; CE, current environment; PE, permanent environment; N, shared nest environment; ID, social partner identity. H and S subscripts denote social effects from helpers or all breed group members, respectively. Variance attributable to social effects were obtained by multiplying fitted variances by average number of social partners. ΔAIC gives difference between model fit and that of the best model and w gives the AIC weight.

Mentions: We first estimated the direct environmental and genetic effects on provisioning rate of parents and helpers (table 1). Given that provisioning rate needs to be an extremely plastic trait to respond to changes in brood demand and load sharing with other carers, individuals were moderately consistent in their feeding rate across days at a nest within a particular year (VCST/VP = 0.24, CI = 0.21, 0.27). Most of the consistency in provisioning rates was from differences between nests (VN/VCST = 0.34, CI = 0.25, 0.43), and each bird's current environment effect (VCE/VCST = 0.44, CI = 0.27, 0.61). Permanent environment (VPE/VCST = 0.08, CI = 0.00, 0.29) and additive genetic effects (VA/VCST = 0.12, CI = 0.00, 0.29) together made up less than one-third of the within-year variance ((VA + VPE)/VCST = 0.20, CI = 0.07, 0.37). Variance components as a proportion of the observed phenotypic variance are plotted under model 2A in figure 2. Heritability, as a proportion of a bird's mean feeding rate each year, was higher when considering only the effort of birds when they were parents (VA/VCST = 0.55, CI = 0.40, 0.73; model 1A; figure 2). We did not find any evidence for a sex difference in direct effects (electronic supplementary material).Figure 2.


Social genetic and social environment effects on parental and helper care in a cooperatively breeding bird.

Adams MJ, Robinson MR, Mannarelli ME, Hatchwell BJ - Proc. Biol. Sci. (2015)

Effect sizes. Variance proportions for fixed and random effects predictors relative to observed phenotypic variance VP. Point estimates are surrounded by 50% (heavy lines) and 80% (thin lines) confidence intervals calculated from parametric bootstrapping. Model 1A fit to parent phenotype; model 2A fit to parent and helper phenotype. Models 1A and 2A include only direct effects; models 1B and 2B add social effect of partner identity; models 1C and 2C split social effect into permanent environment and current environment; models 1D and 2D fit social genetic effects. Variance components: A, additive genetic; CE, current environment; PE, permanent environment; N, shared nest environment; ID, social partner identity. H and S subscripts denote social effects from helpers or all breed group members, respectively. Variance attributable to social effects were obtained by multiplying fitted variances by average number of social partners. ΔAIC gives difference between model fit and that of the best model and w gives the AIC weight.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4590478&req=5

RSPB20150689F2: Effect sizes. Variance proportions for fixed and random effects predictors relative to observed phenotypic variance VP. Point estimates are surrounded by 50% (heavy lines) and 80% (thin lines) confidence intervals calculated from parametric bootstrapping. Model 1A fit to parent phenotype; model 2A fit to parent and helper phenotype. Models 1A and 2A include only direct effects; models 1B and 2B add social effect of partner identity; models 1C and 2C split social effect into permanent environment and current environment; models 1D and 2D fit social genetic effects. Variance components: A, additive genetic; CE, current environment; PE, permanent environment; N, shared nest environment; ID, social partner identity. H and S subscripts denote social effects from helpers or all breed group members, respectively. Variance attributable to social effects were obtained by multiplying fitted variances by average number of social partners. ΔAIC gives difference between model fit and that of the best model and w gives the AIC weight.
Mentions: We first estimated the direct environmental and genetic effects on provisioning rate of parents and helpers (table 1). Given that provisioning rate needs to be an extremely plastic trait to respond to changes in brood demand and load sharing with other carers, individuals were moderately consistent in their feeding rate across days at a nest within a particular year (VCST/VP = 0.24, CI = 0.21, 0.27). Most of the consistency in provisioning rates was from differences between nests (VN/VCST = 0.34, CI = 0.25, 0.43), and each bird's current environment effect (VCE/VCST = 0.44, CI = 0.27, 0.61). Permanent environment (VPE/VCST = 0.08, CI = 0.00, 0.29) and additive genetic effects (VA/VCST = 0.12, CI = 0.00, 0.29) together made up less than one-third of the within-year variance ((VA + VPE)/VCST = 0.20, CI = 0.07, 0.37). Variance components as a proportion of the observed phenotypic variance are plotted under model 2A in figure 2. Heritability, as a proportion of a bird's mean feeding rate each year, was higher when considering only the effort of birds when they were parents (VA/VCST = 0.55, CI = 0.40, 0.73; model 1A; figure 2). We did not find any evidence for a sex difference in direct effects (electronic supplementary material).Figure 2.

Bottom Line: Controlling for other effects, individuals were consistent in their provisioning effort at a given nest, but adjusted their effort based on who was in their social group, indicating the presence of social effects.However, these social effects differed between years and social contexts, indicating a current environment effect, rather than indicating a genetic or permanent environment effect.While this study reveals the importance of examining environmental and genetic sources of social effects, the framework we present is entirely general, enabling a greater understanding of potentially important social effects within any ecological population.

View Article: PubMed Central - PubMed

Affiliation: Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK m@differentialist.info.

ABSTRACT
Phenotypes expressed in a social context are not only a function of the individual, but can also be shaped by the phenotypes of social partners. These social effects may play a major role in the evolution of cooperative breeding if social partners differ in the quality of care they provide and if individual carers adjust their effort in relation to that of other carers. When applying social effects models to wild study systems, it is also important to explore sources of individual plasticity that could masquerade as social effects. We studied offspring provisioning rates of parents and helpers in a wild population of long-tailed tits Aegithalos caudatus using a quantitative genetic framework to identify these social effects and partition them into genetic, permanent environment and current environment components. Controlling for other effects, individuals were consistent in their provisioning effort at a given nest, but adjusted their effort based on who was in their social group, indicating the presence of social effects. However, these social effects differed between years and social contexts, indicating a current environment effect, rather than indicating a genetic or permanent environment effect. While this study reveals the importance of examining environmental and genetic sources of social effects, the framework we present is entirely general, enabling a greater understanding of potentially important social effects within any ecological population.

No MeSH data available.


Related in: MedlinePlus