Diniz et al. Toxicity and genetic analysis of bees Scaptotrigona bipunctata after contamination with insecticide accephate 8 Scientific Electronic Archives Issue ID: Sci. Elec. Arch. Vol. 13 (8) August 2020 DOI: http://dx.doi.org/10.36560/13820201157 Article link http://sea.ufr.edu.br/index.php?journal=SEA&page=article&o p=view&path%5B%5D=1157&path%5B%5D=pdf Powered by DOAJ, AGRIS, Latindex, Journal TOCs, CORE, Discoursio Open Science, Science Gate, GFAR, CIARDRING, Academic Journals Database and NTHRYS Technologies, Portal de Periódicos CAPES, CrossRef, ICI Journals Master List. Toxicity and genetic analysis of bees Scaptotrigona bipunctata after contamination with insecticide acephate T. O. Diniz¹*, N. C. Pereira¹, W. C. S. Pizzaia¹, A. A. Sinópolis-Giglioli¹, B. G. Silva 2 , Y. M. Borges 3 , T. A. Guedes 4 , M. C. C. Ruvolo-Takasusuki¹ 1 Universidade Estadual de Maringá – Departamento de Biotecnologia, Genética e Biologia Celular 2 Escola Superior de Agricultura "Luiz de Queiroz" / USP – Departamento de Ciências Exatas 3 Instituto Federal do Amazonas 4 Universidade Estadual de Maringá – Departamento de Estatística * Author for correspondence: tamirisd.biologa@gmail.com ______________________________________________________________________________________ Abstract. The meliponines can be found in tropical and subtropical regions and is observed in the majority of Latin America. Scaptotrigona bipunctata are stingless bees that build colonies that possess between 2,000 and 50,000 individuals. This study aimed to estimate the toxicity of the insecticide acephate after oral and contact contamination in S. bipunctata. Results revealed differences between the two types of contamination and indicated that S. bipunctata is tolerant to acephate since the mortality rate was low. The findings indicated that there were expression changes of isoenzyme esterases after contamination with the insecticide, which was able to partially inhibit almost all of the enzymes identified in this study. In addition, morphological changes were identified in the midgut of the bees in the first 24 hours of contamination. However, after 48 hours it was observed the regeneration of the peritrophic membrane and other structures, contributing to the survival of the insects. It is essential to propose measures to minimize the impact of agrochemicals on pollinators and this study provides support for investigations on pesticide toxicity in stingless bees. Keywords: organophosphate, esterases, midgut ______________________________________________________________________________________ Introduction The meliponines, also known as stingless bees, are bees that have atrophied sting, have variable size and belongs to the Apidae family (Silva et al., 2012). Scaptotrigona bipunctata belongs to this class of bees and are found in Bolivia, Paraguay and Peru (Witter & Nunes-Silva, 2014). In Brazil, this species is generally found in the Pampas, Atlantic Forest and Pantanal biomes (Camargo & Pedro, 2013). These species possess interesting biological characteristics and it can be used in managed pollination (Venturieri et al., 2011) in tropical and subtropical regions (Slaa et al., 2006). However, there are few studies showing the susceptibility of S. bipunctata to insecticides (Santos et al., 2016). Although the main function of pesticides is to protect agricultural crops against diseases and pests, the application of these substances can cause contamination of soils, water and food, and have negative effects on non-target organisms, such as bees (Desneux et al., 2007). Organophosphates are one of the major classes of insecticides used in pest control, which, together with carbamates and pyrethroids, corresponds to approximately 40% of the pesticide market. This class of insecticides has a broad spectrum of action, causing severe damages to the nervous system of contaminated individuals (Coutinho et al., 2005). It acts by phosphorylating the enzyme acetylcholinesterase, responsible for inactivating the neurotransmitter acetylcholine, blocking its catalytic activity (Bastos et al., 2015). Acephate belongs to the organophosphates class and is used against pests in several crops, such as cotton, peanuts, potatoes, broccoli, citrus, kale, cauliflower, cloves, chrysanthemum, beans, tobacco, melons, peppers, cabbage, tomatoes and soy (Mapa, 2017). In Brazil, this insecticide is