Effects of pesticides on sperm quality in honey bee (Apis mellifera L.) drones

In this study, the effects of pesticides, which are extensively used in Turkish agriculture, on drone semen were investigated. Some of the most used pesticides in Turkey; abamectin, cypermethrin, glyphosate, and spinosad were selected. The study consisted of four pesticide groups, the solvent for these pesticides (methyl alcohol), and a control group, a total of six groups. There was a total of 36 colonies used in the experiment, with six colonies in each group. Before beginning the experiment, the colonies were homogenized, and sister queens were admitted in all colonies. When drone eggs began to form, pesticides were applied to the colonies. Sperm was taken 17 days after the drones emerged reached maturity. Semen volume and sperm count measured by spectrophotometer were recorded, and sperm concentration was calculated based on these two parameters. In addition, sperm length and viability were also assessed. When sperm concentration was examined, the lowest concentration was found in drones collected from abamectin-treated colonies (P < 0.05). The volume of ejaculates collected from bees from colonies treated with abamectin and cypermethrin was found to be lower than that of the other groups (P < 0.05). When the effects of pesticides on sperm length were examined, the sperm length of the abamectin group was the shortest, followed by the control and cypermethrin groups (P < 0.05). The sperm length of the spinosad group was the longest (P < 0.05). Sperm viability in the cypermethrin group was the lowest, followed by the abamectin group (P < 0.05). No differences were found between the control, methyl alcohol, glyphosate, and spinosad groups (P > 0.05). In the study conducted to determine the stress caused by pesticides in the larval period, it was found that abamectin and cypermethrin caused stress at the applied dose in the larval period (P < 0.05).