Apalus bimaculatus (Coleoptera, Meloidae) in the provinces of Sodermanland and southern Uppland - a matter of timing.

摘要

In Sweden, A. bimaculatus has mainly been reported from the area around lake Malaren in southeastern Sweden. To assess its current status in the area, a survey in the provinces of Sodermanland and southern Uppland was conducted. The preferred habitat of the host species Colletes cunicularius consists of areas with sand, mostly south-facing slopes, with Salix in the vicinity. During the spring of 2003 and 2004, suitable sites were visited during the short time when the adults were visible above the ground. A. bimaculatus was spotted in 30 sites situated in twenty-three 5x5 km2 along the eskers in the area. It is crucial to be out early in the season (March to early April), preferably in a sunny weather when the temperature is more than 0 degrees C to detect the species. The largest population consisted of more than 300 individuals. A future decline can be anticipated when sites are shaded out as old gravel pits are reforested, and the trend is currently towards fewer and larger pits, which often lack suitable habitats.