Sessions

Exponential growth of the human population requires increasing demands and interests in food security. Pollinators like Apis mellifera are crucial in maintaining our food abundance and therefore, threats such as those posed by Varroa destructor must be managed successfully.

V. destructor are becoming increasingly resistant to the current chemical acaricides and subsequently new methods must be attained. This study evaluates contact-delivered dsRNA targeting 3 neuro-signalling genes in V. destructor (the RDL1 subunit of the Gamma-aminobutyric acid receptor, acetylcholinesterase-like (AChE) and putative octopamine receptor-like GPCR, Octa2R.) RNA interference may act as species-specific biopesticide and reduce many of the harmful effects of less targeted miticides.

This experiment synthesised gene-specific double-stranded RNA by T7 in vitro transcription. Efficacy was determined by a series of soaking bioassays using phoretic V. destructor. The experiment determined gene knockdown and V. destructor mortality after one hour and after ten hours of immersion at 4 °C followed by an 8-hour period where mites were confined with a host honey bee.

Phenotypic mortality was recorded, and relative transcript abundance was quantified via real-time qPCR (using the 2−ΔΔCt method.) The most significant result from the study was the Octa2R treatment group after ten hours (p=0.0004) Where both target transcript decreased and mortality was proportionately high. This result establishes preliminary evidence in identifying new targets and acts as further proof-of-concept for dsRNA use in topical forms against V. destructor in future integrated Varroa Management programs.