Biology subjects

Chaine, A.

Publications and source records attributed to Chaine, A..

4 recordsLinked to original sources

bioRxiv2025

Dynamic membership drives long-term persistence of sparrow winter social communities

Social groups range from highly stable to highly dynamic over extended periods. Demographic factors like individual lifespans and rates of births, deaths, immigration, and emigration in a population can strongly impact group stability and persistence over time. Highly stable long-term groups are often driven by long-lived core individuals that maintain relationships, kin-structure, or high philopatry. In opposition, fluid groups of individuals that associate repeatedly, called social communities, can persist in populations that have high turnover, lack kin structure, and exhibit high fission-fusion dynamics. However, we lack an understanding of how animal social communities persist amidst highly dynamic membership. We investigated the drivers of persistence of social communities in a winter population of migratory golden-crowned sparrows over 12 years. Sparrows frequently flock with the same individuals over the entire winter, forming social communities that are identified from discrete clusters within a social network. Long-term community membership was highly dynamic due to high annual turnover and the relatively short lifespans of individuals. However, the social fidelity of returning members and recruitment of new members between consecutive years resulted in communities that persisted for multiple years, even when there was a complete turnover of members over time. Our results indicate that groups can persist with consistent short-term membership, overlapping generations, and turnover with balanced rates of recruitment and loss. This dynamic stability of individual membership may be a universal feature of large, long-term groups found in many social systems, from animal societies with fission-fusion dynamics to networks of human collaboration.

animal behavior and cognition↗

bioRxiv2022

Evidence of attack deflection suggests adaptive evolution of wing tails in butterflies

Predation is a powerful selective force shaping many behavioural and morphological traits in prey species. The deflection of predator attacks from vital parts of the prey usually involves the coordinated evolution of prey body shape and colour. Here, we test the deflection effect of hindwing tails in the swallowtail butterfly Iphiclides podalirius. In this species, hindwings display long tails associated with a conspicuous colour pattern. By surveying the wings within a wild population of I. podalirius, we observed that wing damage was much more frequent on the tails. We then used a standardised behavioural assay employing dummy butterflies with real I. podalirius wings to study the location of attacks by great tits Parus major. Wing tails and conspicuous coloration of the hindwings were struck more often than the rest of the body by birds. Finally, we characterised the mechanical properties of fresh wings and found that the tail vein was more fragile than the others, suggesting facilitated escape ability of butterflies attacked at this location. Our results clearly support the deflective effect of hindwing tails and suggest that predation is an important selective driver of the evolution of wing tails and colour pattern in butterflies.

evolutionary biology↗

bioRxiv2020

Children cooperate more successfully with non-kin than with siblings.

Cooperation plays a key role in advanced societies with human cooperation among kin being more prominent than cooperation among non-kin. However, little is known about the developmental roots of kin and non-kin cooperation in humans. Here, we show for the first time that children cooperated less successfully with siblings than with non-kin children, whether or not non-kin partners were friends. Furthermore, children with larger social networks cooperated better and the perception of friendship among non-friends improved after cooperating. These results indicate that non-kin cooperation in humans has deep developmental foundations which might serve to forge and extend non-kin social relationships during middle childhood and create opportunities for future collaboration beyond kin. Our results provide a new framework for future studies focusing on how and why cooperation with different classes of partners may change during development in humans as well as other long-lived organisms.

evolutionary biology↗

bioRxiv2017

Bottom-up and top-down control of dispersal across major organismal groups: a coordinated distributed experiment

Organisms rarely experience a homogeneous environment. Rather, ecological and evolutionary dynamics unfold in spatially structured and fragmented landscapes, with dispersal as the central process linking these dynamics across spatial scales. Because dispersal is a multi-causal and highly plastic life-history trait, finding general drivers that are of importance across species is challenging but highly relevant for ecological forecasting.\n\nWe here tested whether two fundamental ecological forces and main determinants of local population dynamics, top-down and bottom-up control, generally explain dispersal in spatially structured communities. In a coordinated distributed experiment spanning a wide range of actively dispersing organisms, from protozoa to vertebrates, we show that bottom-up control, that is resource limitation, consistently increased dispersal. While top-down control, that is predation risk, was an equally important dispersal driver as bottom-up control, its effect depended on prey and predator space use and whether dispersal occurred on land, in water or in the air: species that routinely use more space than their predators showed increased dispersal in response to predation, specifically in aquatic environments. After establishing these general causes of dispersal, we used a metacommunity model to show that bottom-up and top-down control of dispersal has important consequences for local population fluctuations as well as cascading effects on regional metacommunity dynamics. Context-dependent dispersal reduced local population fluctuations and desynchronized dynamics between communities, two effects that increase population and community stability.\n\nOur study provides unprecedented insights into the generality of the positive resource dependency of dispersal as well as a robust experimental test of current theory predicting that predator-induced dispersal is modulated by prey and predator space use. Our experimental and theoretical work highlights the critical importance of the multi-causal nature of dispersal as well as its cascading effects on regional community dynamics, which are specifically relevant to ecological forecasting.

ecology↗