Altricial birds often display biased preferences in providing parental care for their dependent offspring,especially during food shortages.During this process,such inflexible rules may result in provisioning errors.To...Altricial birds often display biased preferences in providing parental care for their dependent offspring,especially during food shortages.During this process,such inflexible rules may result in provisioning errors.To demonstrate how parents optimize their provisioning strategies,we proposed a“diagnosis model”of parental care to posit that parents will undergo a diagnosis procedure to test whether selecting against some particular offspring based on phenotype is an optimal strategy.We tested this model in an asynchronous hatching bird,the Azure-winged Magpie Cyanopica cyanus,based on 10 years of data about demography and parental provisioning behaviors.Given their higher daily survival rates,core offspring(those hatched on the first day)merits an investment priority compared with their marginal brood mates(those hatched on later days).However,a marginal offspring also merited a priority if it displayed greater weight gain than the expected value at the early post-hatching days.Parents could detect such a marginal offspring via a diagnosis strategy,in which they provisioned the brood at the diagnosis stage by delivering food to every nestling that begged,then biased food toward high-value nestlings at the subsequent decision stage by making a negative response to the begging of low-value nestlings.In this provisioning strategy,the growth performance of a nestling became a more reliable indicator of its investment value than its hatching order or competitive ability.Our findings provide evidence for this“diagnosis model of parental care”wherein parents use a diagnosis method to optimize their provisioning strategy in brood reduction.展开更多
Early experience can prepare offspring to adapt their behaviors to the environment they are likely to encounter later in life. In several species of ants, colonies show ontogenic changes in the brood-to-worker ratio t...Early experience can prepare offspring to adapt their behaviors to the environment they are likely to encounter later in life. In several species of ants, colonies show ontogenic changes in the brood-to-worker ratio that are known to have an impact on worker morphology. However, little information is available on the influence of fluctuations in the early social context on the expression of behavior in adulthood. Using the ant Lasius niger, we tested whether the brood-to-worker ratio during larval stages influenced the level of behavioral variability at adult stages. We raised batches of 20 or 180 larvae in the presence of 60 workers until adulthood. We then quantified the activity level and wall-following tendency of callow workers on 10 successive trials to test the prediction that larvae reared under a high brood-to-worker ratio should show greater behavioral variations. We found that manipulation of the brood-to-worker ratio influenced the duration of development and the size of individuals at emergence. We detected no influence of early social context on the level of between- or within-individual variation measured for individual activity level or on wall-following behavior. Our study suggests that behavioral traits may be more canalized than morphological traits.展开更多
基金This work was supported by the National Natural Science Foundation of China(grants 31370417,31572271,31772465,32071491).
文摘Altricial birds often display biased preferences in providing parental care for their dependent offspring,especially during food shortages.During this process,such inflexible rules may result in provisioning errors.To demonstrate how parents optimize their provisioning strategies,we proposed a“diagnosis model”of parental care to posit that parents will undergo a diagnosis procedure to test whether selecting against some particular offspring based on phenotype is an optimal strategy.We tested this model in an asynchronous hatching bird,the Azure-winged Magpie Cyanopica cyanus,based on 10 years of data about demography and parental provisioning behaviors.Given their higher daily survival rates,core offspring(those hatched on the first day)merits an investment priority compared with their marginal brood mates(those hatched on later days).However,a marginal offspring also merited a priority if it displayed greater weight gain than the expected value at the early post-hatching days.Parents could detect such a marginal offspring via a diagnosis strategy,in which they provisioned the brood at the diagnosis stage by delivering food to every nestling that begged,then biased food toward high-value nestlings at the subsequent decision stage by making a negative response to the begging of low-value nestlings.In this provisioning strategy,the growth performance of a nestling became a more reliable indicator of its investment value than its hatching order or competitive ability.Our findings provide evidence for this“diagnosis model of parental care”wherein parents use a diagnosis method to optimize their provisioning strategy in brood reduction.
基金Funding was provided by CNRS (www.cnrs.fr) and Université Toulouse III (www.univ-tlse3.fr) to R.J. I.S.-V. was funded by a post-doctoral fellowship of the Galician government (Xunta de Galicia, Axudas de apoio á etapa posdoutoral 2017,ref: ED481B-2017/034). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
文摘Early experience can prepare offspring to adapt their behaviors to the environment they are likely to encounter later in life. In several species of ants, colonies show ontogenic changes in the brood-to-worker ratio that are known to have an impact on worker morphology. However, little information is available on the influence of fluctuations in the early social context on the expression of behavior in adulthood. Using the ant Lasius niger, we tested whether the brood-to-worker ratio during larval stages influenced the level of behavioral variability at adult stages. We raised batches of 20 or 180 larvae in the presence of 60 workers until adulthood. We then quantified the activity level and wall-following tendency of callow workers on 10 successive trials to test the prediction that larvae reared under a high brood-to-worker ratio should show greater behavioral variations. We found that manipulation of the brood-to-worker ratio influenced the duration of development and the size of individuals at emergence. We detected no influence of early social context on the level of between- or within-individual variation measured for individual activity level or on wall-following behavior. Our study suggests that behavioral traits may be more canalized than morphological traits.
