Effect of Triclosan on the brain of workers of Apis mellifera (Hymenoptera: Apidae)

Abstract

Triclosan (TCS) is a bacteriostatic agent found in the composition of personal care products, cleaning products, cosmetics, and pesticides. TCS is considered an emerging contaminant, being detected in water bodies and presenting toxicity in the organism of some species. However, there are no studies on the effects of TCS on bees, nor studies related to the nervous system of Apis mellifera. In view of the above, we intend to analyze the effects of TCS on the morphology of Kenyon cells of the pedunculated bodies and antennal lobes of A. mellifera workers. The newly emerged workers will be collected from the comb and then kept in an incubator (33ºC, 70% humidity) for 96 hours, separated into entomological containers containing 10 workers per group. The exposure will be carried out by offering ad libitum a solution contaminated with TCS at 0.001 ppb (Experimental Group 1) and 0.5 ppb (Experimental Group 2), while the control groups will be fed with a 50% sucrose solution (Control Group 1) and 50% sucrose solution containing 0.5 ppb of acetone (Control Group 2), in addition to filtered water. After the exposure period, the bees will be cryoanesthetized and dissected for routine morphological analysis and fluorescence histochemical analysis. Finally, morphometric analyzes will be performed using Image J software to measure the area of the nuclei of different types of Kenyon cells between groups (controls and exposed). Additionally, the area of the antennal lobes and the total area of the pedunculated bodies will be measured and compared between groups. It is important to emphasize the novelty of this research since Triclosan is a ubiquitous substance in ecosystems, but very little is studied in the area of terrestrial ecotoxicology.(AU)