Does the dose make the poison? Neurotoxic insecticides impair predator orientation and reproduction even at low concentrations

Abstract

BACKGROUND Pesticides can be noxious to non‐target beneficial arthropods and their negative effects have been recently recognized even at low doses. The predator Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae) plays an important role in controlling insect pests in solanaceous crops, but its concurrent herbivory often poses relevant concerns for tomato production. Although insecticide side effects on N. tenuis have been previously studied, little is known on the potential implications of neurotoxic chemicals at low concentrations. We assessed the baseline toxicity of three neurotoxic insecticides (lambda‐cyhalothrin, spinosad and chlorpyrifos) on N. tenuis by topical contact exposure. The behavioral and reproduction capacity of the predator was then investigated upon exposure to three estimated low‐lethal concentrations (LC1, LC10 and LC30). RESULTS Predator survival varied among insecticides and concentrations, with LC30/label rate ratios ranging from 8.45% to 65.40% for spinosad and lambda‐cyhalothrin, respectively. All insecticides reduced the fertility of N. tenuis females at all estimated low‐lethal concentrations. Chlorpyrifos seriously compromised predator orientation towards a host plant even at LC1, while the same effect was observed for lambda‐cyhalothrin and spinosad solely at LC30. Lambda‐cyhalothrin (at all concentrations) and chlorpyrifos (at LC10 and LC30) also affected the time taken by N. tenuis females to make a choice. CONCLUSION The results indicate that all three insecticides can be detrimental to N. tenuis and should be avoided when presence of the predator is desirable. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Sublethal effects of plant essential oils toward the zoophytophagous mirid Nesidiocoris tenuis

“…Healthy insects can detect fragrant and chemosensoryactive compounds such as plant volatile compounds through odorant binding proteins and chemosensory proteins, located on the periphery of sensory receptors, with the function to capture and transport molecular stimuli (Picimbon 2005). In our experiment, we were able to observe untreated N. tenuis females highly attracted to sesame plants, as previously reported (Biondi et al 2016;Passos et al 2022). After treatment with the EOs, even at very low concentrations, the orientation of N. tenuis toward a host plant was compromised.…”

“…The N. tenuis individuals used in the bioassays were obtained in the laboratory rearing according to the methodology described by Passos et al (2022). Adults of N. tenuis (~ 150 individuals) were kept in entomological cages (32 × 40 × 70 cm) covered by fine net mesh.…”

“…Thereafter, each N. tenuis male and female was placed into a ventilated arena (400 mL) containing 1 g of E. kuehniella eggs as food supply and a green bean pod (Phaseolus vulgaris L., cv. "Garrafal enana") as oviposition substrate (Passos et al 2022). Nesidiocoris tenuis couples were kept into experimental arenas to mate successfully and allow females to oviposit into green bean pods.…”

Spinosad‐associated modulation of select cytochrome P450s and glutathione S‐transferases in the Colorado potato beetle, Leptinotarsa decemlineata

“…Regarding the latter, the use of spinosad, a natural insecticide produced from Saccharopolyspora spinosa (Mertz & Yao, 1990), has been mentioned as an effective approach to control a variety of insects including L. decemlineata (Dively et al, 2020). Differing effects have been reported following treatment with varying dose of this insecticide in insects such as the mirid bug Nesidiocoris tenuis (Passos et al, 2022) and the fruit fly Drosophila melanogaster (Nguyen et al, 2021). Nevertheless, reports have shown resistance to spinosad in L. decemlineata even though the exact molecular mechanisms underlying this resistance remain to be clarified (Klein et al, 2021; Mota‐Sanchez et al, 2006; Schnaars‐Uvino & Baker, 2021).…”

Characterization of the sublethal toxicity and transcriptome‐wide biological changes induced by λ‐cyhalothrin in Bombyx mori

“…19 Recent studies have reported that sublethal λ-cyh at LC 1 , LC 10 , or LC 30 could seriously compromise the predatory ability, and also reduce the fertility of the predators, including Nesidiocoris tenuis and Chrysoperla sinica. 20,21 Moreover, our previous study showed that λcyh was extremely toxic to B. mori, and continuous exposure to trace λ-cyh (4.5 μg/L, 1/100 LC 50 ) could lead to mild poisoning symptoms to silkworms and cell injuries were occurred in fat body tissues. 22 Due to the serious consequences caused by low pesticide dosages, researches on the sublethal effects may offer new insights for mitigating their detrimental impacts on silkworms.…”