Biology subjects

Araya-Ajoy, Y.

Publications and source records attributed to Araya-Ajoy, Y..

3 recordsLinked to original sources

bioRxiv2026

Fine-scale spatio-temporal variation in natural selection on reproductive traits across two wild bird species

Natural selection drives adaptive evolution and underpins eco-evolutionary processes. However, the causes of variation of selection (strength and direction), and its spatio-temporally scaling, remain poorly understood. Most selection estimates are population-wide, ignoring the variation in fine-scale selection regimes within populations. We quantify variation in selection within sub-populations of a long-term study of great tits (Parus major) and blue tits (Cyanistes caeruleus) in Wytham Woods, UK. Using mixed-effect modelling, we decomposed temporal, spatial and spatio-temporal variation in selection on laying date, clutch size and their correlational selection. Across species, we detected non-linear selection for larger clutch size and earlier laying, and negative correlational selection. Spatio-temporal effects explained most variation in selection across traits and species, suggesting that the causes of selection are controlled by interacting temporal (e.g. climate) and spatial (e.g. habitat) mechanisms. Laying date had strong temporal (among-year) variation for both species, whereas spatial components generally explained little variation. Selection estimates were highly correlated between species for all traits except for correlational selection, with higher agreement when analyzing fledgling versus recruitment numbers. Our results suggest common factors underpinning small-scale spatio-temporal variation in selection in both species and that such analyses can identify the sources causing natural selection.

ecology↗

bioRxiv2024

Towards explaining the fertility gap in farmed Pekin ducks

Maximising reproductive success is crucial to animal production systems, particularly in meeting global demands for animal products and improving commercially important traits. However, while social interactions and mating strategies are known to influence reproductive success in wild populations, their consideration in agricultural systems remains limited. Using an interdisciplinary framework that combines concepts from behavioural ecology and quantitative genetics in an animal breeding context, we investigated the role of sperm limitation and polygynous mating strategies (female polyandry, male monopolisation of females and male polygamy) in limiting female reproductive success in farmed Pekin ducks (Anas platyrthynchos domestica). We assessed the impact of these behaviours on chick production and quantified their genetic and environmental (co)variance. Our results revealed that the number of dam mates positively influenced chick production in female ducks. However, contrary to our expectation, skew in chick paternity (our measure of male monopolisation) was associated with increased female chick production, challenging the hypothesis that male monopolisation limits the sperm available to females and reduces their reproductive success. We found no evidence that male polygamy led to decreased female chick production. Genetic analysis revealed that female mate number and reproductive skew exhibit genetic variance, providing opportunities for targeted selection to enhance chick production. However, there was a negative genetic association between female polyandry and skew in chick paternity, suggesting a trade-off between these traits that would need to be considered in future selection programmes. Our findings highlight how concepts from behavioural ecology can be incorporated into breeding programmes, providing new opportunities to develop effective and sustainable breeding strategies.

evolutionary biology↗

bioRxiv2024

Disentangling the age-dependent causal pathways affecting multiple paternity in house sparrows

The causes of variation in multiple paternity (MP) in socially monogamous birds have received considerable attention. Traits like age and age-dependent morphology have been shown to be important for the distribution of MP. However, most studies fail to separate between the different processes underlying age-effects on MP, such as selective disappearance (that is, higher survival probability for certain phenotypes) versus individually plastic changes in morphology and mating behaviour with age. Using Bayesian multi-level path analysis on a long-term dataset from a house sparrow (Passer domesticus) metapopulation, we disentangle the effects of age on male and female MP, both independently from and through morphological traits. Age was a key determinant of MP for males when accounting for morphological traits, with males having MP more often as they get older (plastic component of age) and not due to disappearance of males unsuccessful to get MP (selective disappearance), challenging good genes explanations for MP. Conversely, selective disappearance explained the higher levels of MP in older females, suggesting that higher quality females have MP more often than lower quality females. We show how an appropriate statistical decomposition of age-components and age-dependent processes provides insights to the biological drivers of MP.

ecology↗