Rosalia alpina adults (Linnaeus, 1758) (Insecta, Coleoptera) avoid direct sunlight

Adults of the threatened beetle species Rosalia alpina are usually associated with sun–exposed dead wood. In previous fieldwork, however, we frequently found adult beetles on shaded surfaces of trees. We thus studied whether adults preferred different lightning conditions depending on their behavior on 447 beech trees located in four forests in two distant locations in Europe. From a total of 542 individuals, we observed that 54 % of them occurred in shaded conditions, and 35 % in predominantly shaded conditions. This avoidance of direct sunlight could be widespread in the species because it was independent of the location and behavior.