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Résumé :

Understanding how groups of animals disperse in space, and how individual behaviours and interactions at small scale determine large-scale patterns of population spread and dispersal, is a long standing goal of ecology. Using a novel experimental set-up and image analysis techniques, I could track the spatial propagation of groups of tiny insects (<0.5 mm) over large temporal and spatial scales (several hours, several metres), that are relevant to population dynamics and biocontrol. Results show that spatial propagation is positively density-dependent, but that this effect is only transient: this produces a “Tortoise-Hare effect” whereby slow diffusers eventually catch-up with the quick starters. The presence of hosts is shown to suppress this transiency of density dependence. Despite our groups being homogeneous phenotypically and genetically, I show that individuals adopt two types of movement strategies (resident and explorer), and switch between them over the course of spatial propagation. This has several consequences for the spatial distribution of individuals and the dispersal kernel. I suggest a simple mathematical model of heterogeneous diffusion with two behavioural modes and switching provides a very good description of the observed patterns.​

Ce séminaire se déroulera en salle A010.

Il sera également possible de suivre la présentation en visio-conférence.
Détails de connexion :
Sujet : Séminaire ISA
Heure : 21 octobre 2022 11:00 AM Paris
Participer à la réunion Zoom
https://inrae-fr.zoom.us/j/5774848300
ID de réunion : 577 484 8300