title: Assessment of thiamethoxam toxicity to Chironomus riparius.
abstract: The insecticide thiamethoxam (TMX) is a systemic neonicotinoid widely used for pest control in several agricultural crops. TMX mimics the action of acetylcholine causing uncontrolled muscular contraction eventually leading to insect death. TMX is being found in freshwater ecosystems at concentrations of up to 225µg/L. Still, chronic toxicity data for freshwater invertebrates is limited. Therefore, the aim of this study was to evaluate the acute and chronic effects (at organismal and biochemical levels) of TMX on the freshwater insect Chironomus riparius. C. riparius life history responses were significantly affected by TMX exposure, namely with a decrease in growth and delay in emergence. Concerning the biochemical responses, after a short exposure (48h) to TMX, our results showed that low concentrations of TMX significantly reduced CAT activity and LPO levels of C. riparius. No effects were observed in AChE, GST and ETS activities. Effects in terms of survival, development rates and biochemical responses of C. riparius exposed to low concentrations of TMX observed in this study suggest potential deleterious effects of this neonicotinoid on aquatic insects inhabiting freshwaters environments near agricultural areas.
authors.affiliation: Departmento de Produção Vegetal, Universidade Federal do Tocantins, Campus Universitário de Gurupi, Rua Badejós, Lote 7, Chácaras 69/72, Zona Rural, PO box 66, CEP: 77402-970 Gurupi, Tocantins, Brazil; Departamento de Biologia & CESAM, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Althiéris S
authors.initials: AS
authors.lastname: Saraiva
authors.affiliation: Departmento de Produção Vegetal, Universidade Federal do Tocantins, Campus Universitário de Gurupi, Rua Badejós, Lote 7, Chácaras 69/72, Zona Rural, PO box 66, CEP: 77402-970 Gurupi, Tocantins, Brazil; Departamento de Biologia & CESAM, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Renato A
authors.initials: RA
authors.lastname: Sarmento
authors.affiliation: Departamento de Biologia & CESAM, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Andreia C M
authors.initials: AC
authors.lastname: Rodrigues
authors.affiliation: Departamento de Biologia & CESAM, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Diana
authors.initials: D
authors.lastname: Campos
authors.affiliation: University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Hydrocenoses, Zatisi 728/II, 389 25 Vodnany, Czechia.
authors.forename: Ganna
authors.initials: G
authors.lastname: Fedorova
authors.affiliation: University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Hydrocenoses, Zatisi 728/II, 389 25 Vodnany, Czechia.
authors.forename: Vladimír
authors.initials: V
authors.lastname: Žlábek
authors.affiliation: Departamento de Biologia & CESAM, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Carlos
authors.initials: C
authors.lastname: Gravato
authors.affiliation: Departmento de Produção Vegetal, Universidade Federal do Tocantins, Campus Universitário de Gurupi, Rua Badejós, Lote 7, Chácaras 69/72, Zona Rural, PO box 66, CEP: 77402-970 Gurupi, Tocantins, Brazil; Departamento de Biologia & CESAM, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal. Electronic address: jpestana@ua.pt.
authors.forename: João L T
authors.initials: JL
authors.lastname: Pestana
authors.affiliation: Departmento de Produção Vegetal, Universidade Federal do Tocantins, Campus Universitário de Gurupi, Rua Badejós, Lote 7, Chácaras 69/72, Zona Rural, PO box 66, CEP: 77402-970 Gurupi, Tocantins, Brazil; Departamento de Biologia & CESAM, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Amadeu M V M
authors.initials: AM
authors.lastname: Soares
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002683:Chironomidae / Q000187:drug effects* / Q000254:growth & development; D005618:Fresh Water / Q000032:analysis; D007313:Insecta / Q000187:drug effects; D007306:Insecticides / Q000633:toxicity*; D007448:Invertebrates / Q000187:drug effects; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D008018:Life Cycle Stages / Q000187:drug effects; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000633:toxicity*; D010078:Oxazines / Q000633:toxicity*; D000077922:Thiamethoxam; D013844:Thiazoles / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010078:Oxazines; D013844:Thiazoles; D014874:Water Pollutants, Chemical; D000077922:Thiamethoxam
keywords: Biochemical responses; Freshwater insects; Life-history traits; Neonicotinoids