Hazards of pesticides to bees - 12 th International Symposium of the ICP-PR Bee Protection Group, Ghent (Belgium), September 15-17, 2014 236 Julius-Kühn-Archiv, 450, 2015 4.20 Reduced-risk insecticides in Neotropical stingless bee species: impact on survival and activity Hudson Vaner V. Tomé 1 , Wagner F. Barbosa 1,2 , Alberto S. Corrêa 3 , Lessando M. Gontijo 4 , Gustavo F. Martins 5 , Raul Narciso C. Guedes 1 1 Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil 2 Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium 3 Departamento de Entomologia e Acarologia, Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo, Piracicaba, São Paulo, Brazil 4 Instituto de Ciências Agrárias, Universidade Federal de Viçosa, Campus Florestal, Florestal, Minas Gerais, Brazil 5 Departamento de Biologia Geral, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil Corresponding author:Raul Narciso C. Guedes, Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG 36570-900, Brazil, Tel. +55 (31) 3899-4008, E-mail: barbosawf@gmail.com Abstract Background: As honeybees are the main pollinator species subject to an intense research regarding effects of pesticides, other ecologically important native bee pollinators have received little attention in ecotoxicology and risk assessment of pesticides in general, and insecticides in particular, some of which are perceived as reduced-risk compounds. Here the impact of three reduced-risk insecticides – azadirachtin, spinosad, and chlorantraniliprole – was assessed in two species of stingless bees, Partamona helleri and Scaptotrigona xanthotrica, which are important native pollinators in Neotropical America. The neonicotinoid imidacloprid was used as a positive control. Results: Spinosad exhibited high oral and contact toxicities in adult workers of both species at the recommended label rates, with median survival times (LT 50 s) ranging from 1 to 4 h, whereas these estimates were below 15 min for imidacloprid. Azadirachtin and chlorantraniliprole exhibited low toxicity at the recommended label rates, with negligible mortality that did not allow LT 50 estimation. Sublethal behavioral assessments of these two insecticides indicated that neither one of them affected the overall group activity of workers of the two species. However, both azadirachtin and chlorantraniliprole impaired individual flight take-off of P. helleri and S. xanthotrica worker bees, which may compromise foraging activity, potentially leading to reduced colony survival. Conclusion: These findings challenge the common perception of non-target safety of reduced-risk insecticides and bioinsecticides, particularly regarding native pollinator species. Keywords: behavioral impact; biopesticides; colony and individual level effects; native bee pollinators; sublethal effects. 1. IntroductionThe honeybee is perceived as very sensitive to insecticides compared to other arthropod species. 1-3 Therefore this species has for some time been the representative model pollinator because it is widely available globally and inexpensive to use as an environmental bioindicator of pesticide pollution. 3,4 However, a recent meta-analysis study provided support for such use of honeybees, a 10-fold sensitivity ratio correction seems necessary for the extrapolation of insecticide toxicity results from the honeybee to other bee species. 5 Such fact has obscured the importance of stingless bees and only little research has undertaken on this topic. 5-8 Stingless bees species are the primary pollinators of wild and cultivated plants in Neotropical America 9-12 and they may be important even in the presence of the honeybee. 5,8,9 Therefore, stingless bees demand more attention regarding the potential effects of pesticides in this particular geographic region. Furthermore, the reliance on the honeybee for insecticide toxicity assessments may compromise more susceptible pollinator species, such as stingless bees, and thus impair agricultural production and plant diversity in the neotropics. 4,13,14 The general focus on the impact of neonicotinoids on pollinators, particularly honeybees, has led to an expansion and incentives of reduced-risk pesticides and particularly of biopesticides. 15-18 The