Within Task 8.3, from May to July, the INHORT (the National Institute of Horticultural Research, Poland) team carried out an experiment involving the controlled infection of the red mason bee (Osmia bicornis) with Chronic Bee Paralysis Virus (CBPV). The aim of this study was to investigate whether this virus, commonly found in the western honey bee (Apis mellifera), can be transmitted to other pollinator species and to evaluate its potential effects.
For the experiment, Osmia cocoons were placed in individual Falcon tubes and incubated for several days in a climatic chamber (see Photo 1). Newly emerged individuals were then subjected to a one-day starvation period. Subsequently, both male and female bees were individually exposed to the virus by directly feeding them a syrup solution containing the viral inoculum at four different concentrations (see Photo 2). Each individual was then placed into a cage equipped with a syringe containing sugar syrup as a food source (see Photo 3). Each group consisted of 40 bees, which together with control group sum up to 400 cages. The cages were kept in a designated room with controlled temperature and humidity following natural day-night cycles (see Photo 4). This setup allowed to maintain stable conditions and to closely monitor the behavior and health status of each bee following infection.
After collecting dead individuals, their intertegular distance will be measured as a proxy for body size, allowing to account for individual size differences in survival analyses. Preliminary observations indicate that males are considerably more susceptible to the virus than females.
Photo 1. Cocoons placed individually in Falcon tubes for emergence
Photo 2. An individual bee fed with syrup containing inoculum of CBPV
Photo 3. A cage with an individual bee
Photo 4. Bees (400 cages) placed in a room with controlled temperature and humidity