Study of insect visitor guild on Calluna vulgaris (L.) Hull in heathlands at mont Lozère

As part of an ongoing research project on the pollination networks in European heathlands, the objective of this study was to assess the insect visitor guild on Calluna vulgaris (L.) Hull (Ericaceae). We focused the study on a region renowned for its largely well-preserved heathlands, the Cévennes National Park, Southern France. In 2013, flower visitors were observed over 3 days per site, in four heathland sites at mont Lozère. Honeybees (Apis mellifera L.) were the main visitors (62–88% of total visitors). The dominance of honeybees is explained by the abundance of hives placed in the heathlands during summer. Besides honeybees, a high diversity of visitors was detected with 57 different species identified (42 Diptera and 15 Hymenoptera). Hoverflies (Syrphidae, Diptera) visitors were abundant and diverse, especially individuals belonging to the genera Eristalis and Episyrphus. Few other hymenoptera species were observed. The diversity of visitors observed confirmed the generalist pollination system of Calluna vulgaris. It was also probably due to the preservation of large heathland areas (1558 ha) at mont Lozère. The impact of artificial and natural afforestation of these heathlands (mainly with Pinus sylvestris) on pollinators has not been demonstrated. However, the forest cover as well as the current changes in grazing practices tend to reduce heather floral density, which could have an impact on pollinators in the next years