The concentration effect of selected acaricides present in beeswax foundation on the survival of Apis mellifera colonies
Sandra K Medici, Adela Castro, Edgardo G Sarlo, Juan M Marioli and Martin J Eguaras
Acaricides used for the control of Varroa destructor are a major source of pollution in a honey bee (Apis mellifera) hive. Because they involve a slow release, they must be present for a period of up to 45 days inside a hive to be effective. The aim of this study was to determine whether the presence of acaricides in beeswax affects the survival of breeding bees, and if this effect is greater at higher concentrations. Three types of recycled beeswax foundation containing paraffin wax in different proportions (0%, 20% and 40%) were used. Brood survival rate was calculated in each treatment (Nº. pupae / Nº. Eggs * 100). Acaricide content in wax sheets was determined by multi-residue analysis by GC-ECD. Survival rate was higher when using beeswax adulterated with paraffin. Recycled beeswax without added paraffin wax (0%) had high levels of coumaphos and fluvalinate contamination, and when paraffin wax was added in different percentages (20%, 40%) the concentration of these components was lower. The presence of acaricides in beeswax adversely affected brood survival. When the pesticide concentration decreased, an improvement in the survival rate was found. Larvae developed in beeswax foundation without paraffin wax, exposed at higher concentration of pollutant residues were more vulnerable to the toxic effects of the acaricides.