Rademacher Eva, Harz Marika, Schneider Saskia
Institute of Biology/Neurobiology, Freie Universität Berlin, Königin-Luise-Str. 28-30, 14195 Berlin, Germany.
Insects. 2017 Aug 7;8(3):84. doi: 10.3390/insects8030084.
: Oxalic acid dihydrate is used to treat varroosis of . This study investigates lethal and sublethal effects of oxalic acid dihydrate on individually treated honeybees kept in cages under laboratory conditions as well as the distribution in the colony. After oral application, bee mortality occurred at relatively low concentrations (No Observed Adverse Effect Level (NOAEL) 50 µg/bee; Lowest Observed Adverse Effect Level (LOAEL) 75 µg/bee) compared to the dermal treatment (NOAEL 212.5 µg/bee; LOAEL 250 µg/bee). The dosage used in regular treatment via dermal application (circa 175 µg/bee) is below the LOAEL, referring to mortality derived in the laboratory. However, the treatment with oxalic acid dihydrate caused sublethal effects: This could be demonstrated in an increased responsiveness to water, decreased longevity and a reduction in pH-values in the digestive system and the hemolymph. The shift towards stronger acidity after treatment confirms that damage to the epithelial tissue and organs is likely to be caused by hyperacidity. The distribution of oxalic acid dihydrate within a colony was shown by macro-computed tomography; it was rapid and consistent. The increased density of the individual bee was continuous for at least 14 days after the treatment indicating the presence of oxalic acid dihydrate in the hive even long after a treatment.
草酸二水合物用于治疗[对象]的蜂螨病。本研究调查了草酸二水合物对在实验室条件下单独饲养于笼中的蜜蜂的致死和亚致死效应，以及其在蜂群中的分布情况。经口服给药后，与经皮给药相比，蜜蜂在相对较低浓度下出现死亡（无观察到有害作用水平（NOAEL）为50微克/只蜜蜂；最低观察到有害作用水平（LOAEL）为75微克/只蜜蜂）（经皮给药的NOAEL为212.5微克/只蜜蜂；LOAEL为250微克/只蜜蜂）。常规经皮给药所用剂量（约175微克/只蜜蜂）低于实验室得出的LOAEL。然而，草酸二水合物处理会导致亚致死效应：这可表现为对水反应性增加、寿命缩短以及消化系统和血淋巴的pH值降低。处理后向更强酸性的转变证实，上皮组织和器官的损伤可能是由酸度增加引起的。通过宏观计算机断层扫描显示了草酸二水合物在蜂群中的分布情况；其分布迅速且一致。处理后至少14天内，单个蜜蜂的密度增加持续存在，这表明即使在处理后很长时间，蜂箱中仍存在草酸二水合物。
