Wagner Faria Barbosa

Bio: Wagner Faria Barbosa is an academic researcher from Universidade Federal de Viçosa. The author has contributed to research in topics: Stingless bee & Spinosad. The author has an hindex of 11, co-authored 35 publications receiving 330 citations.

Biopesticide-induced behavioral and morphological alterations in the stingless bee Melipona quadrifasciata

Abstract: Because of their natural origin, biopesticides are assumed to be less harmful to beneficial insects, including bees, and therefore their use has been widely encouraged for crop protection. There is little evidence, however, to support this ingrained notion of biopesticide safety to pollinators. Because larval exposure is still largely unexplored in ecotoxicology and risk assessment on bees, an investigation was performed on the lethal and sublethal effects of a diet treated with 2 bioinsecticides, azadirachtin and spinosad, on the stingless bee, Melipona quadrifasciata, which is one of the most important pollinators in the Neotropics. Survival of stingless bee larvae was significantly compromised at doses above 210 ng a.i./bee for azadirachtin and 114 ng a.i./bee for spinosad. No sublethal effect was observed on larvae developmental time, but doses of both compounds negatively affected pupal body mass. Azadirachtin produced deformed pupae and adults as a result of its insect growth regulator properties, but spinosad was more harmful and produced greater numbers of deformed individuals. Only spinosad compromised walking activity of the adult workers at doses as low as 2.29 ng a.i./bee, which is 1/5000 of the maximum field recommended rate. In conclusion, the results demonstrated that bioinsecticides can pose significant risks to native pollinators with lethal and sublethal effects; future investigations are needed on the likelihood of such effects under field conditions. Environ Toxicol Chem 2015;34:2149–2158. © 2015 SETAC

Azadirachtin-induced antifeeding in Neotropical stingless bees

Abstract: The ongoing debate regarding the role of pesticides in the global decline of bee populations is increasing the demand for use of biopesticides, compounds generally believed to be less harmful to pollinators. However, there is lack of evidence justifying such perceptions, particularly regarding native pollinator species like Neotropical stingless bees. Here, we investigated whether azadirachtin, a neem-based biopesticide, causes significant lethal and sublethal effects on adult workers of the Neotropical stingless bee species Melipona quadrifasciata and Partamona helleri. Susceptibility to azadirachtin varied with several factors, including the route of exposure, the concentration of the biopesticide, and the bee species. We found that although azadirachtin did not affect worker bee mortality, flight, or respiration rate, it did, however, induce a significant antifeeding effect on the stingless bee species.

A restatement of recent advances in the natural science evidence base concerning neonicotinoid insecticides and insect pollinators

Abstract: A summary is provided of recent advances in the natural science evidence base concerning the effects of neonicotinoid insecticides on insect pollinators in a format (a ‘restatement') intended to be accessible to informed but not expert policymakers and stakeholders Important new studies have been published since our recent review of this field (Godfray et al 2014 Proc R Soc B 281, 20140558 (doi:101098/rspb20140558)) and the subject continues to be an area of very active research and high policy relevance

From the Western Palaearctic region to beyond: Tuta absoluta 10 years after invading Europe

Abstract: The South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a devastating pest currently threatening the global tomato industry worldwide. In the last 10 years, it has spread and expanded to most of Europe, Africa and Asia, causing extensive damage to the crop itself and to the international tomato trade. With the aim of providing an overview of the current knowledge on this pest, we have briefly reviewed the available literature relying on its spread, quarantine, modeling and management. Finally, we have underlined the gaps in knowledge and provided several recommendations on how to achieve sustainable control as well as how to prevent further spread into unaffected areas.

Most dominant roles of insect gut bacteria: digestion, detoxification, or essential nutrient provision?

Abstract: The insect gut microbiota has been shown to contribute to the host’s digestion, detoxification, development, pathogen resistance, and physiology. However, there is poor information about the ranking of these roles. Most of these results were obtained with cultivable bacteria, whereas the bacterial physiology may be different between free-living and midgut-colonizing bacteria. In this study, we provided both proteomic and genomic evidence on the ranking of the roles of gut bacteria by investigating the anal droplets from a weevil, Cryptorhynchus lapathi. The gut lumen and the anal droplets showed qualitatively and quantitatively different subsets of bacterial communities. The results of 16S rRNA sequencing showed that the gut lumen is dominated by Proteobacteria and Bacteroidetes, whereas the anal droplets are dominated by Proteobacteria. From the anal droplets, enzymes involved in 31 basic roles that belong to 7 super roles were identified by Q-TOF MS. The cooperation between the weevil and its gut bacteria was determined by reconstructing community pathway maps, which are defined in this study. A score was used to rank the gut bacterial roles. The results from the proteomic data indicate that the most dominant role of gut bacteria is amino acid biosynthesis, followed by protein digestion, energy metabolism, vitamin biosynthesis, lipid digestion, plant secondary metabolite (PSM) degradation, and carbohydrate digestion, while the order from the genomic data is amino acid biosynthesis, vitamin biosynthesis, lipid digestion, energy metabolism, protein digestion, PSM degradation, and carbohydrate digestion. The PCA results showed that the gut bacteria form functional groups from the point of view of either the basic role or super role, and the MFA results showed that there are functional variations among gut bacteria. In addition, the variations between the proteomic and genomic data, analyzed with the HMFA method from the point of view of either the bacterial community or individual bacterial species, are presented. The most dominant role of gut bacteria is essential nutrient provisioning, followed by digestion and detoxification. The weevil plays a pioneering role in diet digestion and mainly digests macromolecules into smaller molecules which are then mainly digested by gut bacteria.