clothianidin and Body-Weight

Humans are exposed to pesticide residues through various food products. As these residues can occur in mixtures, there is a need to investigate possible mixture effects on human health. Recent exposure studies revealed the preponderance of imazalil, thiacloprid, and clothianidin in food diets. In this study, we assessed their toxicity alone and in binary mixtures in a 28-day gavage study in female Wistar rats. Five dose levels (up to 350 mg/kg bw/day) ranging from a typical toxicological reference value to a clear effect dose were applied. Data show that the liver was a target organ of all pesticides and their mixtures. Increases in liver weight were observed and histopathological examination revealed centrilobular hepatocellular hypertrophy and cytoplasm degeneration for all treatment conditions. No accumulation of hepatic triglycerides was reported. Tissue residue analysis showed altered pesticide residues in the liver and the kidney when being in mixture as compared to the levels of pesticide residues for the single compound treatment, indicating possible toxicokinetic interactions. Overall, all mixtures appeared to follow the additivity concept, even though quantitative analysis was limited for some endpoints due to the semi-quantitative nature of the data, raising no specific concern for the risk assessment of the examined pesticides.

Topics: Animals; Body Weight; Chemical and Drug Induced Liver Injury; Female; Guanidines; Imidazoles; Kidney; Liver; Neonicotinoids; No-Observed-Adverse-Effect Level; Organ Size; Pesticides; Rats; Rats, Wistar; Risk Assessment; Thiazines; Thiazoles

Maintaining bee-friendly habitats in cities and suburbs can help conserve the vital pollination services of declining bee populations. Despite label precautions not to apply them to blooming plants, neonicotinoids and other residual systemic insecticides may be applied for preventive control of lawn insect pests when spring-flowering weeds are present. Dietary exposure to neonicotinoids adversely affects bees, but the extent of hazard from field usage is controversial. We exposed colonies of the bumble bee Bombus impatiens to turf with blooming white clover that had been treated with clothianidin, a neonicotinoid, or with chlorantraniliprole, the first anthranilic diamide labeled for use on lawns. The sprays were applied at label rate and lightly irrigated. After residues had dried, colonies were confined to forage for six days, and then moved to a non-treated rural site to openly forage and develop. Colonies exposed to clothianidin-treated weedy turf had delayed weight gain and produced no new queens whereas those exposed to chlorantraniliprole-treated plots developed normally compared with controls. Neither bumble bees nor honey bees avoided foraging on treated white clover in open plots. Nectar from clover blooms directly contaminated by spray residues contained 171±44 ppb clothianidin. Notably, neither insecticide adversely impacted bee colonies confined on the treated turf after it had been mown to remove clover blooms present at the time of treatment, and new blooms had formed. Our results validate EPA label precautionary statements not to apply neonicotinoids to blooming nectar-producing plants if bees may visit the treatment area. Whatever systemic hazard through lawn weeds they may pose appears transitory, however, and direct hazard can be mitigated by adhering to label precautions, or if blooms inadvertently are contaminated, by mowing to remove them. Chlorantraniliprole usage on lawns appears non-hazardous to bumble bees.

Topics: Analysis of Variance; Animals; Bees; Body Weight; Feeding Behavior; Guanidines; Insecticides; Kentucky; Medicago; Neonicotinoids; ortho-Aminobenzoates; Plant Nectar; Plant Weeds; Reproduction; Thiazoles

Clothianidin was given in the diet to provide levels of 0% (control), 0.003%, 0.006%, and 0.012% from 5 weeks of age of the F(0) generation to 11 weeks of age of the F(1) generation in mice. Selected reproductive and neurobehavioral parameters were measured. In exploratory behavior in the F(0) generation, average time of movement, number of rearing, and rearing time of adult males increased significantly in a dose-related manner. There was no adverse effect of clothianidin on litter size, litter weight, or sex ratio at birth. The average body weight of male and female offspring was increased significantly in a dose-related manner during the early lactation period. With respect to behavioral developmental parameters, swimming head angle at postnatal day (PND) 7 of male offspring was accelerated significantly in a dose-related manner. Negative geotaxis at PND 7 of female offspring was accelerated significantly in a dose-related manner. For movement activity of exploratory behavior in the F(1) generation, number of rearing of female offspring increased significantly in a dose-related manner. Movement time of adult males increased significantly in a dose-related manner. The dose levels of clothianidin in the present study produced several adverse effects in neurobehavioral parameters in mice. Nevertheless, it would appear that the levels of the actual dietary intake of clothianidin are unlikely to produce adverse effects in humans.

Topics: Animals; Behavior, Animal; Body Weight; Diet; Dose-Response Relationship, Drug; Exploratory Behavior; Female; Guanidines; Lactation; Litter Size; Male; Mice; Motor Activity; Neonicotinoids; Reproduction; Sex Ratio; Thiazoles; Toxicity Tests

Imidacloprid has been a major neonicotinoid insecticide for controlling Aphis gossypii (Glover) (Homoptera: Aphididae) and other piercing-sucking pests. However, the resistance to imidacloprid has been recorded in many target insects. At the same time, cross-resistance of imidacloprid and other insecticides, especially neonicotinoid insecticides, has been detected.. Results showed that the level of cross-resistance was different between imidacloprid and tested neonicotinoid insecticides (no cross-resistance: dinotefuran, thiamethoxam and clothianidin; a 3.68-5.79-fold cross-resistance: acetamiprid, nitenpyram and thiacloprid). In the study of sublethal effects, imidacloprid at LC(20) doses could suppress weight gain and honeydew excretion, but showed no significant effects on longevity and fecundity of the imidacloprid-resistant cotton aphid, A. gossypii. However, other neonicotinoid insecticides showed significant adverse effects on biological characteristics (body weight, honeydew excretion, longevity and fecundity) in the order of dinotefuran > thiamethoxam and clothianidin > nitenpyram > thiacloprid and acetamiprid.. The results indicated that dinotefuran is the most effective insecticide for use against imidacloprid-resistant A. gossypii. To avoid further resistance development, the use of nitenpyram, acetamiprid and thiacloprid should be avoided on imidacloprid-resistant populations of A. gossypii.

Topics: Animals; Aphids; Body Weight; Fertility; Guanidines; Imidazoles; Insecticide Resistance; Longevity; Neonicotinoids; Nitriles; Nitro Compounds; Oxazines; Pyrimidines; Reproduction; Survival Analysis; Thiamethoxam; Thiazoles; Toxicity Tests