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Ectoparasite presence and brood size manipulation interact to accelerate telomere shortening in nestling jackdaws
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  • Elisa P Badas,
  • Christina Bauch,
  • Jelle Boonekamp,
  • Ellis Mulder,
  • Simon Verhulst
Elisa P Badas
Complutense University of Madrid

Corresponding Author:[email protected]

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Christina Bauch
University of Groningen
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Jelle Boonekamp
University of Glasgow
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Ellis Mulder
University of Groningen
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Simon Verhulst
University of Groningen
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Early-life conditions impact fitness, but whether the combined effect of extrinsic stressors is additive or synergistic is not well known. This is a major knowledge gap, because exposure to multiple stressors is likely to be frequent. Telomere dynamics may be instrumental when testing whether combined stressor effects are additive or synergistic, because many factors affect telomere shortening, and telomere shortening predicts survival. We evaluated the effects of manipulated brood size and natural infestation by the carnid fly Carnus hemapterus on nestling growth and telomere shortening of wild jackdaws (Corvus monedula). Telomere length, measured in blood using TRF, shortened on average by 264 bp. In enlarged broods, nestlings’ telomeres shortened more when parasitized, while in reduced broods there was no effect of infestation on telomere shortening. We conclude that there is a synergistic effect of number of siblings and Carnus infestation on telomere shortening rate: blood-sucking parasites may negatively impact telomeres by increasing cell proliferation and/or physiological stress, and coping with infestation may be less successful in enlarged broods with increased sibling competition and lower per capita feeding rate. Larger nestlings had shorter telomeres independent of age, brood manipulation or infestation. Growth was independent of infestation but in enlarged broods, nestlings were lighter at fledging. Our findings indicate that (i) evaluating consequences of early-life environmental conditions in isolation may not yield a full picture due to synergistic effects, and (ii) effects of environmental conditions may be cryptic, e.g. on telomeres, with fitness consequences expressed beyond the temporal framework of the study.
28 Jul 2023Submitted to Molecular Ecology
31 Jul 2023Submission Checks Completed
31 Jul 2023Assigned to Editor
31 Jul 2023Review(s) Completed, Editorial Evaluation Pending
09 Aug 2023Reviewer(s) Assigned
19 Sep 2023Editorial Decision: Revise Minor
23 Sep 20231st Revision Received
25 Sep 2023Assigned to Editor
25 Sep 2023Submission Checks Completed
25 Sep 2023Review(s) Completed, Editorial Evaluation Pending