Developing a method to rear Varroa destructor in vitro

Authors: JOHNSON, BRYNN - University Of Florida; PROUTY, CODY - University Of Florida; JACK, CAMERON - University Of Florida; Stuhl, Charles; ELLIS, JAMES - University Of Florida

Submitted to: Experimental and Applied Acarology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/2024
Publication Date: 3/14/2024
Citation: Johnson, B.L., Prouty, C., Jack, C.J., Stuhl, C.J., Ellis, J.D. 2024. Developing a method to rear Varroa destructor in vitro. Experimental and Applied Acarology. https://doi.org/10.1007/s10493-024-00905-8.
DOI: https://doi.org/10.1007/s10493-024-00905-8

Interpretive Summary: Varroa destructor is a significant mite pest of the western honey bee. Developing a method to rear and maintain populations of V. destructor in vitro would provide year-round access to the mites, allowing scientists to study their biology, behavior, and control without seasonal interruption. ARS researchers in Gainesville, Florida in collaboration with the University of Florida investigated the impact of various rearing parameters on V. destructor survival and reproduction outside of the hive environment (in vitro). This was done by collecting V. destructor from honey bee colonies, placing them in gelatin capsules containing a honey bee larva, and manipulated rearing conditions experimentally: temperature, colony source of honey bee larva, behavioral/developmental stages of V. destructor and honey bee larva, and mite: bee larva ratio. Our findings indicated that mite survival was significantly impacted by temperature, colony source of larvae, and mite behavioral stage. In addition, V. destructor reproduction was considerably impacted by mite: larva ratio, larval developmental stage, colony source of larva, and temperature. The following conditions optimized mite survival and reproduction in vitro: using a 4:1 mite: larva ratio, beginning the study with late stage uncapped larvae, using mites collected from adult bees, maintaining the rearing temperature at 34.5° C, and screening larval colony source. The impact of this research will allow for scientist’s accessibility to V. destructor for uninterrupted laboratory experimentation due to seasonal availability.

Technical Abstract: Varroa destructor is a significant mite pest of western honey bees (Apis mellifera). Developing a method to rear and maintain populations of V. destructor in vitro would provide year-round access to the mites, allowing scientists to study their biology, behavior, and control more rapidly. In this study, we determined the impact of various rearing parameters on V. destructor survival and reproduction in vitro. This was done by collecting V. destructor from colonies, placing them in gelatin capsules containing a honey bee larva, and manipulating the following conditions experimentally: rearing temperature, colony source of honey bee larva, behavioral/developmental stages of V. destructor and honey bee larva, and mite:bee larva ratio. Varroa destructor survival was significantly impacted by temperature, colony source of larvae and mite behavioral stage. In addition, V. destructor reproduction was significantly impacted by mite: larva ratio, larval developmental stage, colony source of larva, and temperature. The following conditions optimized mite survival and reproduction in vitro: using a 4:1 mite:larva ratio, beginning the study with late stage uncapped larvae, using mites collected from adult bees, maintaining the rearing temperature at 34.5° C, and screening larval colony source. Ultimately, this research can be used to improve V. destructor in vitro rearing programs.