Biology subjects

Fargevieille, A.

Publications and source records attributed to Fargevieille, A..

2 recordsLinked to original sources

bioRxiv2025

Disentangling urbanisation, climate effects and their interaction on ornamental colourations

Urbanisation and climate change can both affect phenotype expression across taxa. Most evidence collected so far has focused on exploring these two phenomena on isolation. Currently, the combined effects of climate change and urbanisation remain underexplored, despite being among the greatest challenges faced by biodiversity. Here, we use a decade-long, individual-based study of urban and forest great tits (Parus major) to analyse urbanisation, climate and their interactive effects on yellow breast colouration, a carotenoid-based trait. We find that urban birds exhibit duller colourations than forest counterparts, being 10-20% less chromatic, with first-year birds and males being more negatively impacted by cities. Additionally, birds in the city are more sexually dichromatic than in the forest. Over the decade, colouration differences between habitats remain stable, following a similar quadratic temporal pattern. Finally, while climate has a weak effect on colouration, urban birds appear more sensitive to its influence than forest birds. Our results indicate urbanisation has a stronger impact than last decade climatic variation on great tit colouration, though both factors may interact. The heightened sensitivity of first-year birds and increased sexual dichromatism in cities may alter the strength of natural and sexual selection on this trait in urban environments.

ecology↗

bioRxiv2024

The city and forest bird flock together in a common garden: genetic and environmental effects drive urban phenotypic divergence

Urban phenotypic divergences are documented across diverse taxa, but the underlying genetic and environmental drivers behind these phenotypic changes are unknown in most wild urban systems. We conduct a common garden experiment using great tit (Parus major) eggs collected along an urbanization gradient to: 1) determine whether documented morphological, physiological, and behavioural shifts in wild urban great tits are maintained in birds from urban and forest origins reared in a common garden (N = 73) and 2) evaluate how different sources of genetic, early maternal investment, and later environmental variation contributed to trait variation in the experiment. In line with the phenotypic divergence in the wild, common garden birds from urban origins had faster breath rates (i.e., higher stress response) and were smaller than birds from forest origins, while wild differences in aggression and exploration were not maintained in the experiment. Differences between individuals (genetic and environmentally induced) explained the most trait variation, while variation among foster nests and captive social groups was limited. Our results provide trait-specific evidence of evolution in an urban species where genetic change likely underlies urban differences in morphology and stress physiology, but that urban behavioural divergences are more strongly driven by plasticity.

evolutionary biology↗