بررسی سمیت استامی‌پرید و دلتامترین در زنبورعسل ایرانی Apis mellifera meda (Hymenoptera: Apidae) در شرایط آزمایشگاهی

Insecticides are one of the most important factors threatening the honey bee population. Forager bees are most likely to come in contact with pesticides and may be exposed to insecticides while collecting nectar and pollen. Therefore, it is necessary to know the toxicity of insecticides and the poising symptoms caused by them. Acetamiprid and Deltamethrin are common insecticides used in agricultural fields. Therefore, an experiment was conducted with the aim of determining the lethal concentration values for 50% of the population (LC50) of these two insecticides by direct spraying and oral administration in laboratory conditions. For this purpose, five different concentrations of each insecticide were evaluated against forager bees as derived from their recommended field concentrations. This experiment was carried out in temperature conditions of 28±2°C, relative humidity of 40±5% and in 10 hours of light and 14 hours of darkness with at least three repetitions and an approximate number of 20 insects per repetition. Forager bees were collected from the entrance of the hive flight hatch and transported to the laboratory. To reduce genetic and environmental diversity, a single beehive was used. In the direct spraying method, the concentrations used for both insecticides were sprayed on forager bees by a potter spray tower. In the oral administration, a sweet paste composed of a mixture of sugar powder and honey was utilized. In this method, bees were starved for two hours and then fed with the sweet paste combined with the desired insecticides. Statistical analyzes were performed using the probit method and SPSS version 27 software. The results showed that the sensitivity of bees was higher in the direct spraying method than in the oral administration. LC50 of acetamiprid and deltamethrin after 24 hours in direct spraying were estimated as 491/409, 6/614 and in oral administration 1456/199 and 163/571 mg ai/L, respectively. Acetamiprid showed no lethal effect at recommended field concentration, while Deltamethrin caused 100% mortality in direct spraying method. The poisoning symptoms in each insecticide were different and included a bent abdomen, shrinking, paralysis of the third pair of legs, extended proboscis, sting in release-out position and vomiting in the oral method. Poisoning symptoms occurred faster in the direct spraying method than in the oral method.