A review on the resistance to Varroa mites in honeybee (Apis mellifera)

Diseases of honeybee (Apis mellifera) are one of the major challenges for apiculture industry. Among honeybee diseases, Varroa mite is the most serious and extensive threat for this pollinator insect. In compare to other diseases, Varroa is the most costly to beekeepers. Varroa mite, in addition to weakening its host by consuming body tissues, is considered as carrier for many pathogens and viruses. In total, two main strategies are available for confronting Varroa. One of them is using chemical pesticides to remove it, and the other one is the developing resistant host to Varroa. In the past decades, several chemical pesticides have been used to control Varroa. However, this mite is rapidly evolving resistance to those chemicals. Over time, thus effectiveness and efficiency of these acaricides will be decreased. Therefore, it seems that the most important strategy to deal with Varroa is to increase host resistance. One of the key mechanisms is hygienic behavior. This behavior is carried out by workers as a protective behavior against various diseases such as bacteria and fungi and other pathogens. Now, hygienic behavior is considered as a trait at honeybee breeding programs. Another pathway to parasite resistance at honeybee is the ability of the larvae or pupae to prevent the reproduction of parasites in cells. Selected honeybees for this feature are more resistant to Varroa. Selection for resistant honeybees will be more effective when breeder uses molecular genetic techniques.