Declining honey bee health has been a major concern worldwide and the responses of bees to biotic factors has not been fully understood yet. This thesis is divided into three parts: the first two chapters concern the use of propolis, as an extract or as a raw propolis, in adult bees experimentally treated with the microsporidium Nosema ceranae (first chapter) and the parasitic mite Varroa destructor (second chapter); and the third chapter relates to the impact of the predatory wasp Vespula germanica on bee hives. The aim of this three-year study was to investigate the behavioral responses of Apis mellifera to the parasite and the pathogen in laboratory, and observe the behavior of the wasp in an experimental apiary. Our results showed that the lifespan of bees artificially infected with N. ceranae or parasitized by V. destructor increased when bees were treated with propolis compared to untreated bees. In particular, laboratory experiments evidenced that raw propolis had a narcoleptic effect on V. destructor mites, by contact, and propolis extract caused a decrease in spore load of N. ceranae. In the study on the feeding strategies of V. germanica in apiary, our results showed the major role of the wasp as a scavenger, because we found that its diet is based mostly on bee carrions. In order to improve the protection measures of honey bees, it would be important to conduct further studies focusing on impact and control of biotic stress factors of this species.