The effects of crude propolis, its volatiles andethanolic extracts on the ecto-parasitic mite,Varroa destructorand health of the Africansavannah honey bee,Apis mellifera scutellata

Abstract

Propolis is a hive product composed of biologically active plant resins, and has been shown toenhance individual honey bee (Apis melliferaL.) health. Propolis has also been demonstratedto mitigate, in part, the negative effects caused by the ecto-parasitic miteVarroa destructorand its associated viruses on the health of managed European honey bee colonies.However, its effect on the health status of African honey bees remains largely unknown.Here, we found that the African savannah honey bees,A. m. scutellatain Kenya, depositedapproximately two and half-fold more propolis in their colonies during periods of increasedthan reduced worker brood rearing. This finding suggested thatA. m. scutellatamay use highquantities of propolis prophylactically to protect their young brood; yet, we observed nosignificant correlation between the quantity of propolis and the amount of worker brood ormite-infestation level on adult workers. Furthermore, whereas propolis volatiles or propolisplaced in direct contact with the mites had no effect on mite survival under laboratoryconditions, the ethanolic extract of propolis significantly reduced mite survival whencompared with untreated control. These results suggest the presence of mite deterrentcompounds in the ethanolic extract of the African honey bee propolis