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.
Large-scale pesticide application poses a major threat to bee biodiversity by causing a decline in bee populations that, in turn, compromises ecosystem maintenance and agricultural productivity. Biopesticides are considered an alternative to synthetic pesticides with a focus on reducing potential detrimental effects to beneficial organisms such as bees. The production of healthy queen stingless bees is essential for the survival and reproduction of hives, although it remains unknown whether biopesticides influence stingless bee reproduction. In the present study, we investigated the effects of the biopesticide azadirachtin on the survival, behavior, morphology, development, and reproduction of queens of the stingless bee Partamona helleri (Friese, 1900). The neonicotinoid imidacloprid was used as a toxic reference standard. Queens were orally exposed in vitro to a contaminated diet (containing azadirachtin and imidacloprid) during development. Azadirachtin resulted in reduced survival, similarly to imidacloprid, altered development time, caused deformations, and reduced the size of the queens' reproductive organs. All of these factors could potentially compromise colony survival. Results from the present study showed azadirachtin posed a toxicological hazard to P. helleri queens.
The lack of consensus regarding pollinator decline in various parts of the planet has generated intense debates in different spheres. Consequently, much research has attempted to identify the leading causes of this decline, and a multifactorial synergism (i.e., different stressors acting together and mutually potentiating the harmful effects) seems to be the emerging consensus explaining this phenomenon. The emphasis on some stressor groups such as agrochemicals, and pollinators such as the honey bee Apis mellifera, can hide the real risk of anthropogenic stressors on pollinating insects. In the present study, we conducted a systematic review of the literature to identify general and temporal trends in publications, considering the different groups of pollinators and their exposure to agrochemicals over the last 76 years. Through an artificial intelligence (AI)-aided meta-analysis, we quantitatively assessed trends in publications on bee groups and agrochemicals. Using AI tools through machine learning enabled efficient evaluation of a large volume of published articles. Toxicological assessment of the impact of agrochemicals on insect pollinators is dominated by the order Hymenoptera, which includes honey bees. Although honey bees are well-explored, there is a lack of published articles exploring the toxicological assessment of agrochemicals for bumble bees, solitary bees, and stingless bees. The data gathered provide insights into the current scenario of the risk of pollinator decline imposed by agrochemicals and serve to guide further research in this area.Systematic Review Registrationhttps://asreview.nl/.
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.
Características epidemiol ógicas e clínicas de pessoas com úlcera venosa atendidas em unidades municipais de saúde Epidemiological and clinical characteristics of people with venous ulcers attended at municipal health units Características epidemiológicas y clínicas de personas con úlcera venosa atendidas en unidades municipales de salud
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