Ectoparasite presence and brood size manipulation interact to accelerate telomere shortening in nestling jackdaws

Badás, E. P., Bauch, C., Boonekamp, J. J. , Mulder, E. and Verhulst, S. (2023) Ectoparasite presence and brood size manipulation interact to accelerate telomere shortening in nestling jackdaws. Molecular Ecology, 32(24), pp. 6913-6923. (doi: 10.1111/mec.17177) (PMID:37864481)

Abstract

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 frequent. Telomere dynamics may be instrumental when testing how stressors interact because many factors affect telomere shortening, and telomere shortening predicts survival. We evaluated the effect 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, and on average, Carnus infection induced more telomere shortening. Further analyses showed that in enlarged broods, nestlings' telomeres shortened more when parasitized, while in reduced broods there was no effect of infection on telomere shortening. We conclude that there is a synergistic effect of number of siblings and Carnus infection on telomere shortening rate: blood‐sucking parasites may negatively impact telomeres by increasing cell proliferation and/or physiological stress, and coping with infection may be less successful in enlarged broods with increased sibling competition. Larger nestlings had shorter telomeres independent of age, brood manipulation or infection. 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, for example, on telomeres, with fitness consequences expressed beyond the temporal framework of the study.

• Item Type: Articles
• Additional Information: EPB was supported by funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 8444403. CB was supported by a DFG fellowship BA 5422/1-1. JJB was supported by NWO grant 823.01.006 awarded to Franjo Weissing and by NWO grant 823.01.009 awarded to SV, which also covered fieldwork and analyses costs.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Boonekamp, Dr Jelle
• Authors: Badás, E. P., Bauch, C., Boonekamp, J. J., Mulder, E., and Verhulst, S.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Molecular Ecology
• Publisher: Wiley
• ISSN: 0962-1083
• ISSN (Online): 1365-294X
• Published Online: 21 October 2023
• Copyright Holders: Copyright © 2023 The Authors
• First Published: First published in Molecular Ecology 32(24):6913-6923
• Publisher Policy: Reproduced under a Creative Commons License