Extra-pair parentage and personality in a cooperatively breeding bird

Abstract

Why so much variation in extra-pair parentage occurs within and among populations remains unclear. Often the fitness costs and benefits of extra-pair parentage are hypothesised to explain its occurrence; therefore, linking extra-pair parentage with traits such as personality (behavioural traits that can be heritable and affect reproductive behaviour) may help our understanding. Here, we investigate whether reproductive outcomes and success are associated with exploratory behaviour in a natural population of cooperatively breeding Seychelles warblers (Acrocephalus sechellensis) on Cousin Island. Exploratory behaviour correlates positively with traits such as risk-taking behaviour and activity in other wild bird species and might promote extra-pair mating by increasing the rate at which potential extra-pair partners are encountered. We therefore predicted that fast-exploring individuals would have more extra-pair offspring. There is also a potential trade-off between pursuing extra-pair parentage and mate guarding in males. We therefore also predicted that fast-exploring males would be more likely to pursue extra-pair parentage and that this would increase the propensity of their mate to gain extra-pair parentage. We found that neither the total number of offspring nor the number of extra-pair offspring were associated with a male’s or female’s exploratory behaviour. However, there was a small but significant propensity for females to have extra-pair fertilisations in pairs that were behaviourally disassortative. Overall, we conclude that, due to the small effect size, the association between exploratory behaviour and extra-pair paternity is unlikely to be biologically relevant.Significance statementTrue genetic monogamy is rare, even in socially monogamous systems, and multiple factors, such as behaviour, social structure, morphology and physiology, determined by the biological system can cause variation in extra-pair parentage (EPP). Therefore, investigating the inherent differences in these factors among individuals could be informative. We investigated whether reproductive outcomes/success are associated with differences in the propensity to explore novel environments/objects in a promiscuous, island-dwelling cooperatively breeding bird, the Seychelles warbler. Our results showed that exploratory behaviour was not associated with the number of offspring produced by an individual, and thus the long-term fitness consequences of different exploratory tendencies did not differ. We also found that the propensity to engage in EPP in females was higher in dissimilar behavioural pairs, but due to the small effect size, we hesitate to conclude that there are personality-dependent mating outcomes in the population.Electronic supplementary materialThe online version of this article (10.1007/s00265-018-2448-z) contains supplementary material, which is available to authorized users.

Analysis of within-individual variation in extrapair paternity in blue tits (Cyanistes caeruleus) shows low repeatability and little effect of changes in neighborhood

“…Many studies aimed to determine the underlying causes of the observed individual variation in the expression of EPP ( Schlicht et al 2015a ; Baldassarre et al 2016 ; Johnsen et al 2017 ; Edwards et al 2018 ). However, our understanding of this variation remains limited.…”

Age‐dependent changes in infidelity in Seychelles warblers

“…All caught individuals were blood sampled (~25 µl) using brachial venipuncture and DNA from these samples was used for molecular sexing (following Griffiths, Double, Orr, & Dawson, 1998) and genotyping based on 30 microsatellite loci (see: Richardson et al., 2001; Spurgin et al., 2014). Parentage was assigned to 1,554 offspring (1991–2015) using masterbayes 2.52 and used to build a genetic pedigree (see: Edwards, Dugdale, Richardson, Komdeur, & Burke, 2018; Sparks et al, 2020).…”

“…We gathered previously generated parentage data for 934 Seychelles warblers that were assigned parentage with high confidence (≥80%) and that hatched on Cousin Island during main breeding seasons in the period 1997–2014 (Edwards et al., 2018; Hadfield et al., 2006; Richardson et al., 2001; Sparks et al,2020). We used these data to assess the age‐dependent production of EGO by females and the age‐dependent risk of cuckoldry for their social male partner (the dominant male in the group).…”

The bold and the sperm: positive association between boldness and sperm number in the guppy

“…However, studies so far have yielded mixed results on the association between exploration and reproductive success (e.g. [9]) and the meta-analysis did not support the hypothesis of a link between exploratory behaviour and reproductive success [4].…”