Apis mellifera L. (Hymenoptera: Apidae) is the best known and most important worldwide pollinator. This insect is able to pollinate almost 80% of plant species, which provide about 35% of the world's food. In recent years, beekeepers have noticed a considerable reduction of managed colonies and honey production. Every year a large percent of colonies die due to the attack of the ectoparasitic mite Varroa destructor as well as for the use of intensive pesticide treatments. Bee populations may drop considerably in the future, if farmers do not reduce the amount of used pesticides and/or new control strategies are found against Varroa destructor. This global perspective is becoming increasingly important also in South Tyrol, where several insecticides with negative effects on bees were banned and the few remaining can not be used on blooming plants. The aim of this thesis is to monitor bee colonies (Apis mellifera carnica ) during the summer period and to compare the development of 15 hives placed in fruit-growing areas of South Tyrol with another 15 colonies placed in Val d'Ega, a valley without intensive fruit growing orchards. The 30 colonies will be placed in six different sites (five colonies per site): three in the fruit-growing area of South Tyrol (two in Merano and one in Laimburg) and the other three apiaries will be set in Val d'Ega. For each colony we will record dead bees found in underbasket traps placed in front of the hives and we will estimate colony strength by the standard method of Liebefeld. The purpose of this experiment is to find if there is a difference between the development of bee colonies and their mortality in the two tested areas. The experiments will be done in collaboration with the Research Center for Agriculture and Forestry of Laimburg.