Effects of Sublethal Dose of Fipronil on Neuron Metabolic Activity of Africanized Honeybees

• Published in: Archives of environmental contamination and toxicology 2013-04, Vol.64 (3), p.456-466
• Main Authors: Roat, Thaisa Cristina, Carvalho, Stephan M., Nocelli, Roberta C. F., Silva-Zacarin, Elaine C. M., Palma, Mario Sérgio, Malaspina, Osmar
• Format: Article
• Language: English
• Subjects: Aging - metabolism; Animal diseases; Animal, plant and microbial ecology; Animals; Apis mellifera; Applied ecology; Bees; Bees - drug effects; Bees - enzymology; Biological and medical sciences; Brain; Brain - drug effects; Brain - enzymology; Brain - metabolism; Chemical contaminants; Cytochrome; Dose-Response Relationship, Drug; Earth and Environmental Science; Ecotoxicology; Ecotoxicology, biological effects of pollution; Electron Transport Complex IV - metabolism; Environment; Environmental Chemistry; Environmental Health; Environmental monitoring; Environmental Pollutants - toxicity; Enzymes; Fipronil; Fundamental and applied biological sciences. Psychology; General aspects; Humidity; Insecticides; Lethal Dose 50; Metabolism; Monitoring/Environmental Analysis; Mushroom Bodies - drug effects; Mushroom Bodies - enzymology; Mushroom Bodies - metabolism; Nervous system; Neurons - drug effects; Neurons - enzymology; Neurons - metabolism; Pesticides; Plant reproduction; Pollutants; Pollution; Pyrazoles - toxicity; Respiration; Soil Science & Conservation; Statistical analysis; Studies; Toxicity; Toxicity Tests, Acute
• ISSN: 0090-4341; 1432-0703
• DOI: 10.1007/s00244-012-9849-1

Fipronil is a neurotoxic insecticide that inhibits the gamma-aminobutyric acid receptor and can affect gustative perception, olfactory learning, and motor activity of the honeybee Apis mellifera . This study determined the lethal dose (LD 50 ) and the lethal concentration (LC 50 ) for Africanized honeybee and evaluated the toxicity of a sublethal dose of fipronil on neuron metabolic activity by way of histochemical analysis using cytochrome oxidase detection in brains from worker bees of different ages. In addition, the present study investigated the recovery mechanism by discontinuing the oral exposure to fipronil. The results showed that mushroom bodies of aged Africanized honeybees are affected by fipronil, which causes changes in metabolism by increasing the respiratory activity of mitochondria. In antennal lobes, the sublethal dose of fipronil did not cause an increase in metabolic activity. The recovery experiments showed that discontinued exposure to a diet contaminated with fipronil did not lead to recovery of neural activity. Our results show that even at very low concentrations, fipronil is harmful to honeybees and can induce several types of injuries to honeybee physiology.