Toxicological and immunohistochemical testing of honeybees after oxalic acid and rotenone treatmentsAles Gregorc and Maja Ivana Smodis Skerl
Agricultural Institute of Slovenia, Hacquetova 17, 1001 Ljubljana, Slovenia
(Received 10 April 2006 - Revised 14 November 2006 - Accepted 20 December 2006 - Published online 14 June 2007)
Abstract - Bees removed capped brood and young larvae from combs at a greater rate after a rotenone treatment than after an oxalic acid (OA)/sucrose treatment. Rotenone (1%) caused 75.2% of capped brood to be removed, OA (3%) 18.7% and a control treatment, 13.3%. Caged worker bees treated with a 1% rotenone powder, a 3% OA or with a control solution had mortality rates of 10.9%, 5.1% and 1.9% respectively. Rotenone (1%) significantly affected the mortality of brood and adult bees whereas OA (3%), did not. Solutions of 3% OA/32% sucrose, 3.4% OA/47.6% sucrose, 3.7% OA/27.1% sucrose (w/w) and a 32% sugar solution applied to adult bees resulted in death rates of 11%, 14%, 11.2% and 6.5% respectively. Individually treated bees consumed more of a 3% OA solution than solutions with higher OA concentrations. A TUNEL assay detected necrotic cell death in 69% of bee midgut cells 24 h after an OA treatment. Normal cell turnover is approximately 8%.
Key words: Treatment / Apis mellifera / acaricide / TUNEL / cell death / mortality
Corresponding author: Ales.Gregorc@kis.si
© INRA, DIB-AGIB, EDP Sciences 2007