Plant Phenology and seed predation: interactions between gorses and weevils in Brittany (France). - Université de Rennes Accéder directement au contenu
Article Dans Une Revue Entomologia Experimentalis et Applicata Année : 2007

Plant Phenology and seed predation: interactions between gorses and weevils in Brittany (France).

Résumé

Exapion ulicis (Forster) and Exapion lemovicinum (Hoffmann) (Coleoptera: Curculionoidea: Apionidae) are seed predators of the three gorse species occurring in Brittany (France): Ulex europaeus L., Ulex gallii Planch., and Ulex minor Roth. (Fabaceae). Host-plant phenology plays a major role in the relationship between apionid weevils and their gorse species, because larvae develop within gorse pods and adults have to wait for pod dehiscence to be released. We monitored flowering and fruiting phenology of gorse species, weevil reproductive behaviour, and egg-laying patterns in six natural populations in the native area of these gorse species. At each site, U. europaeus, which flowers mainly in spring, was sympatric with one of two autumn flowering gorse species, U. gallii and U. minor. We noticed that E. ulicis laid eggs in spring and was restricted to U. europaeus whereas E. lemovicinum laid eggs in autumn and was restricted to the two autumn-flowering species U. gallii and U. minor. Therefore, host specificity depended on gorse phenology, and not on geographic proximity. In addition, the infested pod content showed that E. ulicis laid several eggs per pod and suggested that females chose pods with the highest numbers of seeds. In contrast, E. lemovicinum laid a single egg per pod and showed no preference for pods with many seeds. Finally, the impact of seed predation by E. ulicis was higher than that of E. lemovicinum.

Dates et versions

hal-00168117 , version 1 (24-08-2007)

Identifiants

Citer

Myriam Barat, Michèle Tarayre, Anne Atlan. Plant Phenology and seed predation: interactions between gorses and weevils in Brittany (France).. Entomologia Experimentalis et Applicata, 2007, 124 (2), pp.167-176. ⟨10.1111/j.1570-7458.2007.00565.x⟩. ⟨hal-00168117⟩
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