Terrestrial adult stages of freshwater insects are sensitive to insecticides (original) (raw)
Environmental Toxicology and Chemistry, 2021
Effects of insecticides on terrestrial adult life stages of otherwise aquatic insects, such as mayflies (Ephemeroptera), stoneflies (Plecoptera), and caddisflies (Trichoptera), are largely unknown. In the present study, a risk model was used to pinpoint the species most likely to experience effects due to spray drift exposure during the adult life stage. Using data from an earlier case study with lambda‐cyhalothrin, 6 species with different life cycle traits were used to explore how life cycle characteristics may influence vulnerability. In addition, we performed a generic calculation of the potential effect on the terrestrial life stages of 53 species (including 47 species with unknown sensitivity). Our approach incorporated temporal and spatial distribution of both the insect and the insecticide, creating different exposure conditions among species due to variation in the relative proportion of the populations present at the time of insecticide spraying. The Ephemeroptera species ...
The Sublethal Effects of Insecticides in Insects
Biological Control of Pest and Vector Insects, 2017
Studies related to the effect of insecticides on insect pests and nontarget organisms, such as natural enemies, are traditionally accessed by the estimative of lethal effects, through mortality data. Due to the limitations of the traditional methods, recent studies in the past three decades are assessing the sublethal effects of insecticides upon several important biological traits of insect pests and natural enemies. Besides mortality, the sublethal dose/concentrations of an insecticide can affect insect biology, physiology, behavior and demographic parameters. In this chapter, many sublethal effects of insecticides were addressed for several chemical groups, such as botanical insecticides, carbamate, diamide, insect growth regulators, neonicotinoid, organochlorides, organophosphates, pyrethroid and others. An accurate assessment of these effects is crucial to acquire knowledge on the overall insecticide efficacy in the management of pest insect populations, as well as on their selectivity toward nontarget organisms.
Environmental Toxicology and Chemistry, 2005
Single-species acute toxicity data and (micro)mesocosm data were collated for 16 insecticides. These data were used to investigate the importance of test-species selection in constructing species sensitivity distributions (SSDs) and the ability of estimated hazardous concentrations (HCs) to protect freshwater aquatic ecosystems. A log-normal model was fitted to a minimum of six data points, and the resulting distribution was used to estimate lower (95% confidence), median (50% confidence), and upper (5% confidence) 5% HC (HC5) values. Species sensitivity distributions for specific taxonomic groups (vertebrates, arthropods, nonarthropod invertebrates), habitats (saltwater, freshwater, lentic, lotic), and geographical regions (Palaearctic, Nearctic, temperate, tropical) were compared. The taxonomic composition of the species assemblage used to construct the SSD does have a significant influence on the assessment of hazard, but the habitat and geographical distribution of the species do not. Moreover, SSDs constructed using species recommended in test guidelines did not differ significantly from those constructed using nonrecommended species. Hazardous concentrations estimated using laboratory-derived acute toxicity data for freshwater arthropods (i.e., the most sensitive taxonomic group) were compared to the response of freshwater ecosystems exposed to insecticides. The sensitivity distributions of freshwater arthropods were similar for both field and laboratory exposure, and the lower HC5 (95% protection with 95% confidence) estimate was protective of adverse ecological effects in freshwater ecosystems. The corresponding median HC5 (95% protection level with 50% confidence) was generally protective of single applications of insecticide but not of continuous or multiple applications. In the latter cases, a safety factor of at least five should be applied to the median HC5.
Bioassay of Insecticides against Three Honey Bee Species in Laboratory Conditions
Cercetari Agronomice in Moldova, 2014
A study was conducted at the Eco-toxicology laboratory in the Department of Agricultural Entomology, University of Agriculture Faisalabad, against three species Apis florea, A. dorsata and A. mellifera of honey bees, to check long-term survival of honeybees when exposed to different insecticides. In this study, we used a modeling approach regarding survival data of caged bees under chronic exposure to seven insecticides (Carbosulfan, Chlorpyrifos, Bifenthrin, Spinosad, Indoxacarb, Emamectin benzoate and Imidacloprid), having three replicates and four concentrations (1000, 500, 250, 125 and 0 ppm). We demonstrate the chronic toxicity induced by these insecticides. Laboratory bioassay of these insecticides showed that carbosulfan and imidacloprid were the most toxic at their high dose (1000 ppm) with LT50of 4 hours in each case for A. mellifera, chlorpyrifos and imidacloprid were the most toxic at their high dose (1000 ppm) with LT50 of 5 hours in each case for A. florea whereas chlorpyrifos was the most toxic at high dose (1000 ppm) with LT50 of 5 hours for A. dorsata. However, LT50 of spinosad was increased up to 18 hrs with decreasing concentrations at 125 ppm against A. mellifera, LT50 of spinosad was increased up to 15 hrs with decreasing concentrations at 125 ppm against A. florea as well as LT50 of spinosad and Emamectin benzoate was increased up to 20 hrs with decreasing concentrations at 125 ppm against A. dorsata. However, LT50 of all controlled species was 91-103 hrs.
Bioassay of Insecticides Against Three Honey Bees, 2014
A study was conducted at the Ecotoxicology laboratory in the Department of Agricultural Entomology, University of Agriculture Faisalabad, against three species Apis florea, A. dorsata and A. mellifera of honey bees, to check long-term survival of honeybees when exposed to different insecticides. In this study, we used a modeling approach regarding survival data of caged bees under chronic exposure to seven insecticides (Carbosulfan, Chlorpyrifos, Bifenthrin, Spinosad, Indoxacarb, Emamectin benzoate and Imidacloprid), having three replicates and four concentrations (1000, 500, 250, 125 and 0 ppm). We demonstrate the chronic toxicity induced by these insecticides. Laboratory bioassay of these insecticides showed that carbosulfan and imidacloprid were the most toxic at their high dose (1000 ppm) with LT 50 of 4 hours in each case for A. mellifera, chlorpyrifos and imidacloprid were the most toxic at their high dose (1000 ppm) with LT 50 of 5 hours in each case for A. florea whereas chlorpyrifos was the most toxic at high dose (1000 ppm) with LT 50 of 5 hours for A. dorsata. However, LT 50 of spinosad was increased up to 18 hrs with decreasing concentrations at 125 ppm against A. mellifera, LT 50 of spinosad was increased up to 15 hrs with decreasing concentrations at 125 ppm against A. florea as well as LT 50 of spinosad and Emamectin benzoate was increased up to 20 hrs with decreasing concentrations at 125 ppm against A. dorsata. However, LT 50 of all controlled species was 91-103 hrs.
The Science of the total environment, 2018
Neonicotinoid insecticides used in agriculture can enter freshwater environments in pulses; that is, a short-term period of a higher concentration, followed by a period of a comparatively lower concentration. Non-target aquatic arthropods are exposed to these fluctuating concentrations of neonicotinoids. The present study investigated the potential latent effects of a single environmentally-relevant 24-h pulse of imidacloprid and thiamethoxam, in separate experiments, on the early life-stages of four aquatic arthropods (Hyalella azteca, Chironomus dilutus, Hexagenia spp., and Neocloeon triangulifer). At least three nominal pulse concentrations were tested for each neonicotinoid-species combination: 2.5, 5, and 10 μg L, which were based on environmental monitoring in Ontario, Canada. After exposure to the pulse, organisms were assessed for survival and immobilization. Surviving organisms were then moved into clean water for a chronic post-treatment period, where endpoints including s...
A study on lethal doses of various pesticides on honeybees ( Apis mellifera L.) – a laboratory trial
Physiological Entomology, 2020
Exposure of honeybee (Apis mellifera L.) to pesticides disturbed normal physiological and behavioral functions required for normal foraging and colony maintenance. The present study was aimed towards establishing the mean lethal concentration (LC 50) of three pesticides viz. carbamate (carbaryl), organophosphate (chlorpyrifos) and neonicotinoid (imidacloprid) in honeybees through feeding bioassay laboratory trial. Deleteriousness was confirmed through mortality rate, number of survival bees, acetylcholinesterase (AChE), total protein (TP) levels, AChE gene transcription level, and gut tissues histological analysis of exposed honeybees. Mean mortality rate was calculated for 96 h interval at three different concentrations of tested pesticides (5, 2.5, and 1.25 mg L −1), and LC 50 values calculated for 48 and 96 h interval. AChE enzyme and TP level are determined by ELIZA and spectrophotometer, respectively. Results revealed that imidacloprid had the lowest LC 50 (0.477 ng/bee) values as compared with carbaryl and chlorpyrifos. High mortality rate was observed at highest dose, being impidacloprid have more lethal effects as compared with other pesticides. Similarly, biochemical analysis revealed that imidiacloprid and chlorpyrifos significantly (P ≤ 0.05) increased AChE and TP levels, whereas carbaryl significantly (P ≤ 0.05) decreased them. Similarly, probe based RT qPCR revealed that imidacloprid and chlorpyrifos treatments significantly (P ≤ 0.05) enhanced the AChE level whereas carbaryl decreased it. Histological analysis showed that the gut tissues of honeybees exposed to pesticide treatment had substantial morphological abnormalities. In a nutshell, imidacloprid, carbaryl and chlorpyrifos have substantial toxic effects on all the study attributes of honeybees with imidacloprid being most toxic.
Effects of the herbicides hexazinone and triclopyr ester on aquatic insects
Ecotoxicology and Environmental Safety, 1992
Experiments were conducted to measure acute lethal response of aquatic insects to hexazinone (Velpar L) and triclopyr ester (Garlon 4) in flow-through laboratory bioasays, and to determine lethal and behavioral effects ofthese herbicides on insects in outdoor stream channels. No signilicant mortality (x2 P > 0.05) occurred in 13 test species exposed to hexazinone in laboratory flowthrough bioassays (I-hr exposure, 4%hr observation) at the maximum test concentration of 80 mg/liter. The survival of insects exposed to 80 mg/liter hexazinone in outdoor stream channels was likewise unaffected. Significant drift (x2 P < 0.001) of Isonychia sp. occurred during a hexazinone treatment of the stream channels, but only at the maximum concentration of 80 mg/ liter, and survival of the displaced Zsonychia sp. was not affected. In flow-through bioassays with triclopyr ester, 10 of 12 test species showed no significant mortality at concentrations greater than 80 mgJliter. Survival of Isogenoides sp. and Dolophilodes distinctus was significantly affected at less than 80 mg/liter. Lethal concentrations were estimated by probit analysis of concentrationresponse data (I-hr exposure, 48-hr observation) for Simulium sp. (LCsO = 303 mg/liter), Isogenoides sp. (LCsO = 61.7 mgjliter), and D. distinctus (LCW = 0.6 mg/liter). Triclopyr ester applications to the stream channels resulted in significant drift and mortality of D. distinctus at 3.2 mglliter (no effects at 0.32 mglliter), isogenoides sp. at 32 mg/liter, and Hydropsyche sp. and Epeorus vitrea at 320 mg/liter. The risk to aquatic insects of these herbicides used in forest vegetation management IS discussed. 0