Bee-to-bee contact drives oxalic acid distribution in honey bee colonies

Nine divided hives were constructed to study the distribution of oxalic acid (OA). Experimental colonies were split into two equal, queenright sections with one of three divider types. The first divider allowed trophallaxis to occur between adult bees on each side, but did not allow bee-to-bee contact. The second divider did not allow trophallaxis or bee-to-bee contact. The third divider allowed both bee-to-bee contact and trophallaxis between the two sides. All three dividers allowed gas exchange of volatile materials. The objective was to investigate factors that contribute to the distribution of OA in a hive by monitoring Varroa destructor mortality. Forty mL of a 3.5% OA sugar water solution was trickled on one side of the divider. Sticky boards were used to quantify mite fall before, during, and after OA treatment on both treated and untreated sides. Trophallactic interactions and fumigation did not significantly influence the distribution of OA. Bee-to-bee contact was the primary route for OA distribution.