Interaction between flower-visiting insects and aromatic fennel crops (Foeniculum vulgare): influence of local and landscape variables and implications for anethole production ; Interactions entre insectes floricoles et cultures de fenouil aromatique (Foeniculum vulgare) : influences des variables locales et paysagères et implications pour la production d’anéthole

Fennel is an aromatic mass-flowering crop cultivated in Provence (France), characterized by lavender crops, for its essential oil that contains anethole, a compound of food and economical interest for the elaboration of anise drinks. The realization of controlled pollinations (flowers pollinated by insects and flowers not accessible to insects) demonstrated a drop in fruit production of 86% in the absence of flying insects. The use of coloured pan-traps and net captures in fennel field revealed that the landscape configuration and the vicinity of fennel fields to semi-natural habitats (SNH) positively influence the richness of flying insects. This richness influences then positively the amount of essential oil but negatively the amount of anethole. At the field level, bee visitation rate (mainly driven by honey bees) and species richness positively influence the amount of anethole. The nectar production dynamic of lavender and fennel was also explored thanks to simulation model to identify how insect foraging behaviours could change the daily nectar production. We showed that nectar production for both species is insect visitation driven, but the nectar of lavandin flowers is replenished more quickly. However, visits were more frequent on fennel, probably due to the general nature of the flower and its pollen supply. From a management point of view, we suggest maintaining complex landscape configurations of diversified habitats, to sustain both the crop production of fennel and insect biodiversity. ; Le fenouil est une plante aromatique à floraison massive cultivée en Provence (France), caractérisé par la culture de lavandin, pour son huile essentielle (HE) contenant de l’anéthole d’intérêt économique pour la fabrication du pastis. La réalisation de pollinisations contrôlées (fleurs pollinisées par les insectes et fleurs non-accessibles aux insectes) a démontré une chute de la production de fruits de 86% en absence d’insectes floricoles. L’utilisation de pièges colorés et de captures au filet dans les parcelles ...