Neonicotinoid insecticides are associated with a decline in the diversity and distribution of bees and wasps (Hymenoptera: Aculeata). The effects of neonicotinoids on the metamorphosis of aculeates have never been addressed in detail; however, recent evidence suggests that neonicotinoids induce wing abnormalities. We hypothesized that the metamorphosis success of bees and wasps differs in response to contact exposure to field-realistic concentrations of neonicotinoid insecticides or in response to combined exposure to neonicotinoid insecticides and benzimidazole fungicides. We treated prepupae of the model crabronid wasp Pemphredon fabricii with field-realistic concentrations of four neonicotinoids, acetamiprid, imidacloprid, thiacloprid and thiamethoxam, and/or with the benzimidazole fungicide thiabendazole. Treatment with acetamiprid or imidacloprid decreased the pupation rates to only 39% and 32%, respectively. Treatment with thiacloprid or thiamethoxam did not affect the pupation rate when applied alone, but the subsequent treatment of thiacloprid- or thiamethoxam-treated prepupae with thiabendazole led to significant decreases in pupation rates. A high concentration of acetamiprid, which severely affected the pupation rates, had moderate effects on metamorphosis into adults, resulting in 53% metamorphosis success (as opposed to 95% metamorphosis success in the water-treated group). However, imidacloprid or thiamethoxam treatment resulted in only 5%-10% metamorphosis success into adults. Overall survival decreased in response to treatment with any of the neonicotinoids or benzimidazoles or their combinations, with extremely low survival (<2%) following combined treatment with imidacloprid and thiabendazole or thiamethoxam and thiabendazole. In conclusion, neonicotinoids alter insect metamorphosis success, which can be further potentiated by their combination with other agrochemicals, such as benzimidazoles.
Thousands of tons of neonicotinoids are widely used around the world as broad-spectrum systemic insecticides and veterinary drugs. Researchers originally thought that neonicotinoids exhibited low mammalian toxicity. However, following their widespread use, it became increasingly evident that neonicotinoids could have various toxic effects on vertebrates and invertebrates. The primary focus of this review is to summarize the research progress associated with oxidative stress as a plausible mechanism for neonicotinoid-induced toxicity as well as neonicotinoid metabolism. This review summarizes the research conducted over the past decade into the production of reactive oxygen species, reactive nitrogen species, and oxidative stress as aresult of neonicotinoid treatments, along with their correlation with the toxicity and metabolism of neonicotinoids. The metabolism of neonicotinoids and protection of various compounds against neonicotinoid-induced toxicity based on their antioxidative effects is also discussed. This review sheds new light on the critical roles of oxidative stress in neonicotinoid-induced toxicity to nontarget species.
- MeSH
- Antioxidants adverse effects pharmacology MeSH
- Insecticides adverse effects pharmacology MeSH
- Humans MeSH
- Neonicotinoids adverse effects pharmacology MeSH
- Oxidative Stress drug effects MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Review MeSH
The application of pesticides and chemical fertilizers constitutes a potential risk to human and animals due to the presence of their residues in the food. Thiacloprid belongs to a group of neonicotinoid insecticides. It shows a cytotoxic/cytostatic effect in human peripheral blood lymphocytes probably due to DNA damage. The use of thiacloprid is increasingly widespread worldwide, therefore is very important the assessment of its possible genotoxic and cytotoxic effects on a living organism. That is the reason why we studied the thiacloprid influence on the structure and stability of DNA in presented work. We have been studied the thiacloprid interaction with calf thymus DNA. Association constant was determined by fluorescence spectroscopy using equilibrium receptor-ligand binding analysis. The thermal denaturation of DNA was used to identify the mode of interaction. Viscosity changes were recorded to confirm/disconfirm the intercalation mode of interaction. Given the results, we can conclude that neonicotinoid pesticide thiacloprid destabilizes DNA. It changes the structure and stability of DNA through binding into the minor groove by hydrophobic or hydrogen interactions.
Impacts of neonicotinoids on non-target insects, including aquatic species, may significantly influence ecosystem structure and functioning. The present study investigated the sensitivity of Chironomus riparius to imidacloprid exposures during 24-h, 10- and 28-days by assessing larval survival, growth, emergence and oxidative stress-related parameters. C. riparius exhibited high sensitivity compared to other model aquatic species with acute 24-h LC50 being 31.5 μg/L and 10-days LOEC (growth) 0.625 μg/L. A 28-days partial life cycle test demonstrated imidacloprid effects on the emergence of C. riparius. Exposure to sublethal concentrations during 10-days caused an imbalance in the reduced and oxidized glutathione (GSH and GSSG), and slightly induced lipid peroxidation (increased malondialdehyde, MDA). Our results indicate that oxidative stress may be a relevant mechanism in the neonicotinoid toxicity, reflected in the insect development and life cycle parameters.
- MeSH
- Chironomidae drug effects MeSH
- Nitro Compounds toxicity MeSH
- Insecta MeSH
- Neonicotinoids toxicity MeSH
- Oxidative Stress MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
Agroecosystems are subject to regular disturbances that cause extinction or migration of much of their fauna, followed by recolonization from surrounding refuges. In small-sized aeronaut spiders, such recolonization is potentiated by their ability to rappel and balloon. These are complex behaviors that we hypothesized to be affected by neurotoxins, namely, neonicotinoids. We tested this hypothesis using two common farmland spider species, Oedothorax apicatus (Linyphiidae) and Phylloneta impressa (Theridiidae). The spiders were topically exposed by dorsal wet application or tarsal dry exposure to commercial neonicotinoid formulations Actara 25 WG, Biscaya 240 OD, Mospilan 20 SP and Confidor 200 OD at concentrations that are recommended for application in agriculture. Contact exposure to neonicotinoids suppressed the ability of spiders to produce the major ampullate fiber and anchor it to the substratum by piriform fibrils. Contact exposure to neonicotinoids also suppressed the ballooning behavior that was manifested by climbing to elevated places, adopting a tiptoe position and producing silk gossamer in the wind. Impaired ability of affected common farmland spiders to quickly recolonize disturbed agroecosystems by silk-mediated dispersal may explain their decline in multiple farmland ecosystems, in which neonicotinoids are applied.
- MeSH
- Ecosystem * MeSH
- Farms * MeSH
- Silk metabolism MeSH
- Insecticides pharmacology MeSH
- Neonicotinoids pharmacology MeSH
- Spiders metabolism MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Determining the side effects of pesticides on pollinators is an important topic due to the increasing loss of pollinators. We aimed to determine the effects of chronic sublethal exposure of the neonicotinoid pesticide imidacloprid on the bumblebee Bombus terrestris under laboratory conditions. The analytical standard of imidacloprid in sugar solution was used for the treatment. Verification of pesticides using UHPLC-QqQ-MS/MS in the experimental bumblebees showed the presence of only two compounds, imidacloprid and imidacloprid-olefin, which were found in quantities of 0.57 ± 0.22 and 1.95 ± 0.43 ng/g, respectively. Thus, the level of the dangerous metabolite imidacloprid-olefin was 3.4-fold higher than that of imidacloprid. Label-free nanoLC-MS/MS quantitative proteomics of bumblebee heads enabled quantitative comparison of 2883 proteins, and 206 proteins were significantly influenced by the imidacloprid treatment. The next analysis revealed that the highly downregulated markers are members of the terpenoid backbone biosynthesis pathway (KEGG: bter00900) and that imidacloprid treatment suppressed the entire mevalonate pathway, fatty acid synthesis and associated markers. The proteomics results indicate that the consequences of imidacloprid treatment are complex, and the marker changes are associated with metabolic and neurological diseases and olfaction disruption. This study provides important markers and can help to explain the widely held assumptions from biological observations. SIGNIFICANCE: The major finding is that all markers of the mevalonate pathway were substantially downregulated due to the chronic imidacloprid exposure. The disbalance of mevalonate pathway has many important consequences. We suggest the mechanism associated with the novel toxicogenic effect of imidacloprid. The results are helpful to explain that imidacloprid impairs the cognitive functions and possesses the delayed and time cumulative effect.
Honeybee losses have been attributed to multiple stressors and factors including the neonicotinoid insecticides (NIs). Much of the study of hive contamination has been focused upon temperate regions such as Europe, Canada and the United States. This study looks for the first time at honey, pollen and bees collected from across the Nile Delta in Egypt in both the spring and summer planting season of 2013. There is limited information upon the frequency of use of NIs in Egypt but the ratio of positive identification and concentrations of NIs are comparable to other regions. Metabolites of NIs were also monitored but given the low detection frequency, no link between matrices was possible in the study. Using a simple hazard assessment based upon published LD50values for individual neonicotinoids upon the foraging and brood workers it was found that there was a potential risk to brood workers if the lowest reported LD50was compared to the sum of the maximum NI concentrations. For non-lethal exposure there was significant risk at the worst case to brood bees but actual exposure effects are dependant upon the genetics and conditions of the Egyptian honeybee subspecies that remain to be determined.
- MeSH
- Imidazoles MeSH
- Insecticides analysis MeSH
- Environmental Pollutants analysis MeSH
- Environmental Monitoring * MeSH
- Neonicotinoids MeSH
- Pollen chemistry MeSH
- Seasons MeSH
- Bees chemistry MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Egypt MeSH
Pesticides can enter aquatic environments potentially affecting non-target organisms. Unfortunately, the effects of such substances are still poorly understood. This study investigated the effects of the active neonicotinoid substance thiacloprid (TH) and the commercial product Calypso 480 SC (CA) (active compound 40.4% TH) on Mytilus galloprovincialis after short-term exposure to sublethal concentrations. Mussels were tested for seven days to 0, 1, 5 and 10 mg L-1 TH and 0, 10, 50 and 100 mg L-1 CA. For this purpose, several parameters, such as cell viability of haemocytes and digestive cells, biochemical haemolymph features, superoxide dismutase (SOD) and catalase (CAT) enzymatic activity of gills and digestive gland, as well as histology of such tissues were analysed. The sublethal concentrations of both substances lead to abatement or completely stopping the byssal fibres creation. Biochemical analysis of haemolymph showed significant changes (P < 0.01) in electrolytes ions (Cl-, K+, Na+, Ca2+, S-phosphor), lactate dehydrogenase (LDH) enzyme activity and glucose concentration following exposure to both substances. The TH-exposed mussels showed significant imbalance (P < 0.05) in CAT activity in digestive gland and gills. CA caused significant decrease (P < 0.05) in SOD activity in gills and in CAT activity in both tissues. Results of histological analyses showed severe damage in both digestive gland and gills in a time- and concentration-dependent manner. This study provides useful information about the acute toxicity of a neonicotinoid compound and a commercial insecticide on mussels. Nevertheless, considering that neonicotinoids are still widely used and that mussels are very important species for marine environment and human consumption, further researches are needed to better comprehend the potential risk posed by such compounds to aquatic non-target species.
- MeSH
- Water Pollutants, Chemical toxicity MeSH
- Hemocytes drug effects MeSH
- Hemolymph drug effects MeSH
- Insecticides toxicity MeSH
- Catalase metabolism MeSH
- Mytilus drug effects MeSH
- Neonicotinoids toxicity MeSH
- Superoxide Dismutase metabolism MeSH
- Toxicity Tests, Acute MeSH
- Thiazines toxicity MeSH
- Cell Survival MeSH
- Dose-Response Relationship, Drug MeSH
- Gills drug effects enzymology MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
Neonicotinoid insecticides are increasingly recognized for their role as information disruptors by modifying the chemical communication system of insects and therefore decreasing the chances of reproduction in target insects. However, data from spiders are lacking. In the present study, we tested the responses of males of a common agrobiont spider, Pardosa agrestis, to the application of field-realistic concentration of acetamiprid, which was formulated as Mospilan, and trace amounts of thiacloprid, which was formulated as Biscaya. We applied fresh or 24-h-old residues of Mospilan or Biscaya to the males just prior to the experiment or treated only the surface of a tunnel containing female draglines. We evaluated the ability of the males to recognize female cues from female dragline silk in a Y-maze. The field-realistic, sublethal doses of Mospilan altered pheromone-guided behavior. The choice of the tunnel with female draglines by males was hampered by tarsal treatment of the males with 24 h-old residues of Mospilan. The mating dance display was commonly initiated in control males that came into contact with female draglines and was suppressed by the Mospilan treatments in all three experimental settings. Some males only initiated the mating dance but did not manage to complete it; this was particularly true for males that were treated tarsally with fresh Mospilan residues, as none of these males managed to complete the mating dance. All three experimental settings with Mospilan decreased the frequency of males that managed to both select the tunnel with female draglines and complete the mating dance. The responses to the low-dose Biscaya were much milder and the study was not sufficiently powered to confirm the effects of Biscaya; however, the surprisingly observed trends in responses to very low Biscaya concentrations call for further analyses of long-term effects of trace amounts of neonicotinoids on the pheromone-guided behavior of spiders. These are the first conclusive data regarding the effects of commercially available formulations of neonicotinoid insecticides on the intraspecific chemical communication of spiders.
Neonicotinoids are thought to have negligible repellent or anti-feeding effects. Based on our preliminary observations, we hypothesized that the contamination of spider prey with commonly used neonicotinoids has repellent or feeding deterrent effects on spiders. We tested this hypothesis by providing prey treated or not with field-realistic concentrations of neonicotinoids to the spiders and determining the number of (a) killed only and (b) killed and eaten prey. We exposed adult freshly molted and starved Pardosa agrestis, a common agrobiont lycosid species, to flies treated with neonicotinoids (acetamiprid, imidacloprid, thiacloprid and thiamethoxam) at field-realistic concentrations or with distilled water as a control. There were no effects of the exposure of the prey to neonicotinoids on the number of flies captured. However, the spiders consumed less of the prey treated with neonicotinoids compared to the ratio of control prey consumed, which resulted in increased overkilling (i.e., killing without feeding). In female P. agrestis, the overkilling increased from only 2.6% of control flies to 25-45% of neonicotinoid-treated flies. As the spiders avoided consuming the already captured neonicotinoid-treated prey, the sublethal effects of neonicotinoids extend beyond the simple attractivity/deterrence of the prey itself. The present study demonstrated that prey overkilling serves as a physiological response of spiders to the contact with the prey contaminated with agrochemicals. We speculate that primary contact with neonicotinoids during prey capture may play a role in this unexpected behavior.
- MeSH
- Nitro Compounds toxicity MeSH
- Farms MeSH
- Insecticides toxicity MeSH
- Neonicotinoids toxicity MeSH
- Spiders physiology MeSH
- Feeding Behavior drug effects MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
