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.

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 .…”

“…Studies have reported various effects of neem products on non-target species, such as mites, parasitoids and bees. [24][25][26][27][28][29] For example, behaviour and morphological alterations have been highlighted in bees, 29 while Bernades et al 27 did not detect any effect on worker bee mortality, flight, or respiration rate. The large panel of potentially affected functions and apparent contradictory conclusions are caused by the level of action of azadirachtin.…”

Larvicidal activities of limonoids from Turraea abyssinica (Meliaceae) on Tuta absoluta (Meyrick)

“…Limonoids and especially azadirachtin have been found to have subtle growth-disrupting effects on diverse insect pests (Abdelgaleil & Nakatani, 2003;Bilker et al, 2002;Ndung'u et al, 2004;Gonçalves-Gervásio & Vendramim) but non-toxic to mammal cells (Arona et al, 2004). However, the currently most used limonoid-based insecticide, azadirachtin, can compromise the fertility of insect natural enemies of pests, such as those attacking T. absoluta (Biondi, Desneux, Siscaro, & Zappalà, 2012;Biondi et al, 2013), and affect the behaviour of pollinators (Barbosa, De Meyer, Guedes, & Smagghe, 2014;Bernardes, Tomé, Barbosa, Guedes, & Lima, 2017). Therefore, before proposing the use of these new chemicals in Integrated pest Management Programs, comprehensive analyses of the potential non-target effects on beneficial organisms should be carried out.…”