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Age-related patterns of yolk androgen deposition consistent with adaptive brood reduction in spotless starlings

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  • معلومة اضافية
    • Publisher Information:
      2019
    • نبذة مختصرة :
      Female birds can influence the early development of their offspring by adjusting egg size or by a differential egg resource allocation. Maternal investment can be shaped by natural selection, given the fitness costs related to parental effort. Among egg components, yolk androstenedione (A4) and testosterone (T) play an important role in affecting the behaviour, growth and survival of the offspring. Despite their relevance for nestling development, the factors accounting for within- and between-clutch variations are poorly known. By a cross-sectional sampling, we tested the effect of female age, laying order and laying date on the deposition of yolk A4 and T. We found a lack of differences in overall yolk androgen levels across ages. However, different age females showed specific deposition patterns considering laying order and laying date. Comparing first-year with older females, our results revealed that yolk T levels did not change with female age at the beginning of the breeding season, whereas first-year females transferred lower hormone levels at the end of the breeding season. Within clutches, both androgens increased across the laying sequence, suggesting that late nestlings benefit from an increased allocation that could compensate hatching asynchrony. However, when considering A4 we found that, whereas older females always increased A4 levels across the laying sequence, first-year females did not increase it when environmental conditions became hardest, thus increasing the likelihood of brood reduction. These findings support that yolk androgen variation is particularly important at the within-clutch scale, by providing females with a tool to modify nestling hierarchies.
    • الموضوع:
      póster de congreso
    • Availability:
      Open access content. Open access content
      closedAccess
    • Note:
      English
    • Other Numbers:
      CTK oai:digital.csic.es:10261/217517
      12th European Ornithologists’ Union Congress (2019)
      1286552224
    • Contributing Source:
      CSIC
      From OAIster®, provided by the OCLC Cooperative.
    • الرقم المعرف:
      edsoai.on1286552224
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