Exposure to a sublethal concentration of imidacloprid and the side effects on target and nontarget organs of Apis mellifera (Hymenoptera, Apidae)

Author(s)

Catae, Aline Fernanda ^[1] ; Roat, Thaisa Cristina ^[1] ; Pratavieira, Marcel ^[1] ; da Silva Menegasso, Anally Ribeiro ^[1] ; Palma, Mario Sergio ^[1] ; Malaspina, Osmar ^[1]

Affiliation

^[1] UNESP Univ Estadual Paulista, Dept Biol, Ctr Estudos Insetos Sociais, Inst Biociencias, Campus Rio Claro, Rio Claro, SP - Brazil

• Document type: Journal article
• Source: ECOTOXICOLOGY; v. 27, n. 2, p. 109-121, MAR 2018.
• Web of Science Citations: 14

Abstract

The use of insecticides has become increasingly frequent, and studies indicate that these compounds are involved in the intoxication of bees. Imidacloprid is a widely used neonicotinoid; thus, we have highlighted the importance of assessing its oral toxicity to Africanized bees and used transmission electron microscopy to investigate the sublethal effects in the brain, the target organ, and the midgut, responsible for the digestion/absorption of food. In addition, the distribution of proteins involved in important biological processes in the brain were evaluated on the 1st day of exposure by MALDI-imaging analysis. Bioassays were performed to determine the Median Lethal Concentration (LC50) of imidacloprid to bees, and the value obtained was 1.4651 ng imidacloprid/mu L diet. Based on this result, the sublethal concentration to be administered at 1, 4 and 8 days was established as a hundredth (1/100) of the LC50. The results obtained from the ultrastructural analysis showed alterations in the midgut cells of bees as nuclear and mitochondrial damage and an increase of vacuoles. The insecticide caused spacing among the Kenyon cells in the mushroom bodies, chromatin condensation and loss of mitochondrial cristae. The MALDI-imaging analysis showed an increase in the expression of such proteins as vascular endothelial growth factor receptor, amyloid protein precursor and protein kinase C, which are related to oxygen supply, neuronal degeneration and memory/learning, and a decrease in the expression of the nicotinic acetylcholine receptor alpha 1, which is fundamental to the synapses. These alterations demonstrated that imidacloprid could compromise the viability of the midgut epithelium, as well as inhibiting important cognitive processes in individuals, and may be reflected in losses of the colony. (AU)

• FAPESP's process: 14/14070-3 - Effects of imidacloprid on proteins distribution in the brain of Melipona scutellaris Latreille, 1811 (Hymenoptera, Apidae, Meliponini)
• Grantee: Aline Fernanda Catae
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 12/13370-8 - How is the reaction of the Apis mellifera brain to a sublethal dose of thiamethoxam?
• Grantee: Thaisa Cristina Roat
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 12/50197-2 - Action of products used in cultivation of sugar cane on non-target organisms
• Grantee: Carmem Silvia Fontanetti Christofoletti
• Support Opportunities: Program for Research on Bioenergy (BIOEN) - Thematic Grants