title: Spinosad in the native stingless bee Melipona quadrifasciata: regrettable non-target toxicity of a bioinsecticide.
abstract: The risks imposed by novel insecticides, mainly bioinsecticides, are largely unknown despite their increased use and their perceived environmental safety, which is based on their natural origin. Furthermore, unlike honeybees, native pollinator species have received little attention. In the present study, the lethal and sublethal effects of the neonicotinoid imidacloprid and the bioinsecticide spinosad were assessed in the stingless bee species Meliponaquadrifasciata, an important native pollinator in the Neotropical region. The adult stingless bee workers exhibited high oral insecticide susceptibility, with LD50s of 23.54 and 12.07 ng a.i./bee for imidacloprid and spinosad, respectively. Imidacloprid also impaired worker respiration and overall group activity and flight, while spinosad significantly impaired only worker flight despite exhibiting higher oral toxicity to adult workers than imidacloprid. These findings indicate the hazardous nature not only of imidacloprid but also the bioinsecticide spinosad to adult workers of the native pollinator M. quadrifasciata. Therefore, bioinsecticides should not be exempted from risk assessment analysis due to their lethal and sublethal components.
authors.affiliation: Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG 36570-900, Brazil.
authors.forename: Hudson Vaner V
authors.initials: HV
authors.lastname: Tomé
authors.affiliation: Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG 36570-900, Brazil.
authors.forename: Wagner F
authors.initials: WF
authors.lastname: Barbosa
authors.affiliation: Departamento de Biologia Geral, Universidade Federal de Viçosa, Viçosa, MG 36570-900, Brazil.
authors.forename: Gustavo F
authors.initials: GF
authors.lastname: Martins
authors.affiliation: Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG 36570-900, Brazil. Electronic address: guedes@ufv.br.
authors.forename: Raul Narciso C
authors.initials: RN
authors.lastname: Guedes
mesh_terms: D000818:Animals; D001516:Bees / Q000187:drug effects*; D001938:Brazil; D004338:Drug Combinations; D005247:Feeding Behavior / Q000187:drug effects; D005426:Flight, Animal / Q000187:drug effects*; D007093:Imidazoles / Q000633:toxicity*; D007306:Insecticides / Q000633:toxicity*; D007928:Lethal Dose 50; D018942:Macrolides / Q000633:toxicity*; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000633:toxicity*; D012119:Respiration / Q000187:drug effects; D012919:Social Behavior
chemical_list: D004338:Drug Combinations; D007093:Imidazoles; D007306:Insecticides; D018942:Macrolides; D000073943:Neonicotinoids; D009574:Nitro Compounds; C082359:imidacloprid; C415329:spinosad
keywords: Behavior; Group activity; Native pollinators; Neonicotinoids; Spinosyns; Sublethal impact