Anthophilous insects' seasonal variation in Corsican thermo-Mediterranean shrubland maquis.

Abstract

Background: In any ecosystems, seasonality is a key factor conditioning the temporal variation on an annual scale in combination with differences in the organism phenology. This seasonality is marked in the Mediterranean Region with four contrasting seasons: a hot, dry summer, a mild winter and sometimes a very rainy spring and autumn. With a large surface area and its large range of habitats from seaside to alpine biotopes, Corsica Island represents a biodiversity hotspot with a high rate of endemism. Amongst diverse groups, insects, notably the main orders of pollinators composed of Coleoptera, Hymenoptera, Diptera and Lepidoptera, represent a large proportion of the insular richness.

New information: Our sampling effort focused on the insects from these four orders visiting flowers in a characteristic thermo-Mediterranean vegetation. Our database is an insight into the Corsican anthophilous insects biodiversity from three sites separated by a few kilometres in the region of Ajaccio (SW Corsica) during nine consecutive months in 2023, completing our database for the year 2022 published in this journal. In total, 3714 specimens were sampled in 2023 and 311 species or morpho-species identified from 154 genera and 50 families. Coleoptera were by far the most abundant order representing about 54% of the sampled specimens. The most diverse order was the Hymenoptera representing 44% of the species. Our continuous survey has shown that these orders vary between seasons both in terms of abundance and diversity, resulting in changing communities.