Differences in the oxidative balance of dispersing and non-dispersing individuals: an experimental approach in a passerine bird.

Charlotte Récapet,Stéphane Blanc,Pierre Bize,Alexandre Zahariev,François Criscuolo,Mathilde Arrivé,Blandine Doligez

doi:10.1186/s12862-016-0697-x

Abstract

BackgroundDispersal is often associated with a suite of phenotypic traits that might reduce dispersal costs, but can be energetically costly themselves outside dispersal. Hence, dispersing and philopatric individuals might differ throughout their life cycle in their management of energy production. Because higher energy expenditure can lead to the production of highly reactive oxidative molecules that are deleterious to the organism if left uncontrolled, dispersing and philopatric individuals might differ in their management of oxidative balance. Here, we experimentally increased flight costs during reproduction via a wing load manipulation in female collared flycatchers (Ficedula albicollis) breeding in a patchy population. We measured the effects of the manipulation on plasmatic markers of oxidative balance and reproductive success in dispersing and philopatric females.ResultsThe impact of the wing load manipulation on the oxidative balance differed according to dispersal status. The concentration of reactive oxygen metabolites (ROMs), a marker of pro-oxidant status, was higher in philopatric than dispersing females in the manipulated group only. Differences between dispersing and philopatric individuals also depended on habitat quality, as measured by local breeding density. In low quality habitats, ROMs as well as nestling body mass were higher in philopatric females compared to dispersing ones. Independently of the manipulation or of habitat quality, plasma antioxidant capacity differed according to dispersal status: philopatric females showed higher antioxidant capacity than dispersing ones. Nestlings raised by philopatric females also had a higher fledging success.ConclusionsOur results suggest that dispersing individuals maintain a stable oxidative balance when facing challenging environmental conditions, at the cost of lower reproductive success. Conversely, philopatric individuals increase their effort, and thus oxidative costs, in challenging conditions thereby maintaining their reproductive success. Our study sheds light on energetics and oxidative balance as possible processes underlying phenotypic differences between dispersing and philopatric individuals.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-016-0697-x) contains supplementary material, which is available to authorized users.

Highlights

Dispersal is often associated with a suite of phenotypic traits that might reduce dispersal costs, but can be energetically costly themselves outside dispersal
Female body mass and body composition Female body mass did not differ according to dispersal status (F1,165 = 2.43, P = 0.12), wing load manipulation (F1,152 = 1.09, P = 0.30) or plot density (F1,12 = 2.02, P = 0.18); all interactions between these variables were nonsignificant
We experimentally investigated whether dispersing and philopatric individual differ in metabolic markers during reproduction depending on the energetic demand

Summary

Introduction

Dispersal is often associated with a suite of phenotypic traits that might reduce dispersal costs, but can be energetically costly themselves outside dispersal. Individual dispersal propensity often covaries with other behavioural, morphological and physiological traits [6,7,8], a covariation which can have a genetic as well as environmental basis [9, 10] These associations of traits are thought to have evolved because they reduce time and energy costs during the movement phase and/or exploration and competition costs during settlement in the new habitat [11]. Dispersing individuals can show morphological adaptations to movement, such as larger wings or fat store [12, 13] They show behavioural and physiological adaptations to competitive encounters, such as higher aggressiveness [14], and to the exploration of a new habitat, such as higher exploratory behaviour [10, 15, 16], lower xenophobia [12] or higher immune response [12, 17]

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