Imidacloprid-induced pathophysiological damage in the midgut of Locusta migratoria (Orthoptera: Acrididae) in the field

Abstract

Neonicotinoids are modern insecticides widely used in agriculture worldwide. Their impact on target (nervous system) and non-target (midgut) tissues has been well studied in bene cial insects including honeybees. However, their effects on pest insects on the eld are comparably rarely described. Here, we have studied the effects of the neonicotinoid imidacloprid on the midgut of the pest insect Locusta migratoria caught in the eld. We found that in the midgut of imidacloprid-exposed locusts the activity of enzymes involved in reactive oxygen metabolism was perturbed. By contrast, the activity of P450 enzymes that have been shown to be activated in a detoxi cation response and that were also reported to produce reactive oxygen species was elevated. Probably as a consequence, markers of oxidative stress including protein carbonylation and lipid peroxidation accumulated in midgut samples of these locusts. Histological analyses revealed that their midgut epithelium is disorganized and that the brush border of the epithelial cells is markedly reduced. Indeed, microvilli are signi cantly shorter, misshapen and possibly non-functional in imidacloprid-treated locusts. We hypothesize that imidacloprid induces oxidative stress in the locust midgut, thereby changing the shape of midgut epithelial cells and probably in turn compromising their physiological function. Presumably, these effects reduce the survival rate of imidacloprid-treated locusts and the damage they cause in the eld. BackgroundBecause of its devastating impact on agriculture, the locust Locusta migratoria migratorioides is considered the most economic important pest in Assuit governorate in Upper Egypt. The existing control methods against these pest rely on chemical insecticides such as imidacloprid, chlorpyriphos, malathion and others (El-Saad et al. 2017), which are harmful to the environment and potentially also to humans.Since their introduction in the nineties of the last century, neonicotinoids have become the most widelyused chemical class of insecticide in many countries (Casida &Durkin 2013, Jeschke &Nauen 2008, Jeschke et al. 2011, Tomizawa &Casida 2005. Due to their speci city to insects concomitant with low acute toxicity to non-insects and their versatility in application methods, neonicotinoids constitute an attractive tool in modern agriculture (Elbert et al. 2008, Thompson et al. 2020). However, concerns over neonicotinoids are emerging, and in the European Union, for instance, the use of several neonicotinoids has been widely restricted because of their adverse effects on honeybees (https://ec.europa.eu/food/plants/pesticides/approval-active-substances/renewalapproval/neonicotinoids_en) (Thompson et al. 2020, Wood &Goulson 2017. Hence, for the next future, it is important to assess the impact of neonicotinoids and to understand their effects on the insect at the molecular and cellular levels.Neonicotinoids target primarily at the nervous systems of insects as agonists of postsynaptic acetylcholine receptors by binding especially to the α su...

Feeding deterrence and midgut histomorphological alterations in Spodoptera littoralis larvae treated with separate and combined imidacloprid and spinosad

“…Likewise, we have not come across any direct reference on the histopathological effects of imidacloprid on midgut of 4 th -instar larvae of S. littoralis. However, in our current study, the histological changes induced in the midgut of the 4 th larval instars of S. littoralis treated with imidacloprid was similar to these obtained by [52] for the midgut of Locusta migratoria treated with the same insecticide. Also, the histopathological alterations of imidacloprid and tannic acid on the larvae of Culex pipiens showed that the treated larvae had cytopathological alterations of the midgut epithelium, muscular layers, and epithelial cells [53].…”

Effects and potential resistance induced by imidacloprid and clothianidin insecticides in the German cockroach (Blatella germanica L.)

“…The P450 enzymes conjugate with oxygen molecules and obtain energy from NADPH to penetrate oxygen into the substrate/insecticide. P450 monooxygenase enzyme activity has been linked to insecticide resistance in various studies (Siegfried and Scot 1992;Pridgeon et al 2003; Wolfe and Scharf 2022) and regular prolonged intoxication results in elevated enzyme activity (Hu et al 2020;El-Samad et al 2022). In the current study, continuous long-term exposure to imidacloprid and clothianidin disrupted the P450 system in cockroaches and the insecticide-induced changes in the activities of enzymes involved in metabolism.…”

Entomotherapeutic Role of Periplaneta americana Extract in Alleviating Aluminum Oxide Nanoparticles-Induced Testicular Oxidative Impairment in Migratory Locusts (Locusta migratoria) as an Ecotoxicological Model

“…The study of the harmful effects of metal NPs on the reproductive system using insects as bioindicators has recently come to light in order to evaluate environmental pollution and comprehend critical biological problems [ 12 , 13 ]. Recently, migratory locusts, Locusta migratoria (Linnaeus, 1758), have received a lot of attention for their use in environmental toxicity assessments because they have inherent advantages, such as a short life cycles and non-specific living demands [ 12 , 14 , 15 ]. Significantly, the immune system of L. migratoria comprises humoral-based and cell-mediated immune reactions, including the synergy of hemocytes, fat bodies, and circulating hemolymph peptides for the elimination or deactivation of xenobiotics [ 15 ].…”