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.

Proteomic Profiling Analysis of Male Infertility inSpodoptera LituraLarvae Challenged with Azadirachtin and its Potential‐Regulated Pathways in the Following Stages

“…Azadirachtin was reported to be able to impair development of the reproductive system in several insect species, including Partamona helleri queens, Tuta absoluta , and Drosophila melanogaster . Moreover, azadirachtin‐induced imbalance in the titer of ecdysteroid and juvenile hormone could make great contributions to the abnormal development in reproductive system and have influences on reproduction via impairment of oogenesis and vitellogenesis, reducing mating probability and motility . In this study, the effect of azadirachtin on the reproduction in male S.litura was recorded, and iTRAQ combined with molecular evidence was applied to isolate the azadirachtin‐responsive proteins in male reproductive organ of S.litura to uncover the detailed mechanism.…”

Azadirachtin effects on mating success, gametic abnormalities and progeny survival in Drosophila melanogaster (Diptera)

“…Previously, azadirachtin was reported to impair, with variable effects, the survival of different insect species . Strong variations in insects' susceptibility to azadirachtin were noted depending on insect order, species, formulation, or the method of application . Sensitivity of insects to insecticides varies also with the regulation of plasma membrane receptor and/or ion channels, penetration rate through the cuticle, absorption by insects, transport in tissues of the body and metabolism …”

“…Studies have reported various effects of neem products on non‐target species, such as mites, parasitoids and bees . For example, behaviour and morphological alterations have been highlighted in bees, while Bernades et al . did not detect any effect on worker bee mortality, flight, or respiration rate.…”

“…However, because azadirachtin acts as an insect growth disruptor, negative side effects on beneficial arthropods are expected. Studies have reported various effects of neem products on non‐target species, such as mites, parasitoids and bees . For example, behaviour and morphological alterations have been highlighted in bees, while Bernades et al .…”

L’azadirachtine, un pesticide naturel aux effets multiples

“…L'azadirachtine agit en effet comme un régulateur de croissance, ou perturbateur du développement (comme les agonistes ou antagonistes des ecdystéroïdes et de l'hormone juvénile) [6,7]. Un impact de ce type de produits sur les arthropodes utiles n'est donc pas à écarter [33] et plusieurs études, bien que controversées, ont révélé la toxicité des produits issus du margousier sur des espèces non visées [34][35][36][37]. Ainsi, chez les abeilles, des altérations comportementales et morphologiques ont été observées chez les individus soumis à l'azadirachtine, mais aucun effet sur la viabilité (pour les abeilles ouvrières), le vol ou sur la respiration n'a été mis en évidence [36,37].…”