A sublethal dose of thiamethoxam impaired the foraging and discrimination ability of the ant Camponotus japonicas

This project was designed to evaluate the immunotoxicological effects of thiamethoxam (TMX). One-day-old broiler chicks (total of 90) were procured and maintained under standard housing conditions and divided into five groups for 45 days. Group A kept as control. Different doses of TMX were administered through crop tube containing 50, 100, 200, and 400 mg/kg bwt/daily to groups B, C, D, and E, respectively. Immunological parameters including response to sheep red blood cells (SRBCs), avian tuberculin responses and carbon clearance assay were accessed. It was observed that response to SRBCs including IgM and IgG, avian tuberculin and phagocytic responses are adversely affected in a dose-dependent manner with TMX toxicity. Hence it was concluded from the results that TMX is responsible for immunosuppression in broiler chicks even at different sub-lethal doses.

Neonicotinoids harm especially bumblebees and other species in agricultural areas all over the world. The toxic effect of thiamethoxam from the neonicotinoid group has been little studied especially on bees. This research aimed to evaluate the effects of thiamethoxam on the immune system cells of Bombus terrestris workers. Different ratios of 1/1000, 1/100 and 1/10 of the recommended maximum application dose of thiamethoxam formed the experimental groups. Ten foraging workers were used for each dose and control groups. Contamination was ensured by spraying the prepared suspensions at different ratios to the bees for 20s at a pressure of 1atm. The effects of thiamethoxam on the structures of immune system cells of bumblebees and the amount of these cells were investigated after 48h of exposure. In general, anomalies such as vacuolization, cell membrane irregularities and cell shape changes were detected in prohemocyte, plasmatocyte, granulocyte, spherulocyte and oenocytoid in each dose group. Hemocyte area measurements in all groups were examined comparatively between groups. In general, granulocyte and plasmatocyte sizes were decreased, while spherulocyte and oenocytoid were increased. It was also determined that there was a significant decrease in the amount of hemocytes in the 1 mm3 hemolymph as dose increased. The results of the study revealed that sublethal doses of thiamethoxam negatively affected hemocytes and their amounts of B. terrestris workers.

The green peach aphid, Myzus persicae Sulzer, is an important sap-sucking pest of many plants, including Chinese cabbage. The objective of the present study was to determine the effects of sublethal concentrations of two insecticides (flonicamid and thiamethoxam) and the action mechanisms on the feeding behavior of M. persicae. The median lethal concentrations (LC50) of flonicamid and thiamethoxam for adult M. persicae were 2.56 and 4.02 mg/L, respectively. The sublethal concentrations of flonicamid were 0.44 mg/L (LC10) and 1.25 mg/L (LC30), and those of thiamethoxam were 1.19 mg/L (LC10) and 2.45 mg/L (LC30). The developmental period of M. persicae nymphs was 5.9 days at LC10 and 6.1 days at LC30 for both insecticides compared to 5.7 days for the control. Adult longevities at LC10 and LC30 of flonicamid were 13.2 and 13.7 days, respectively. Adult longevity at LC10 of thiamethoxam was 14.7 days. Control adult longevity was 11.6 days. Total fecundity was higher at LC10 (41.8 offspring/female) and LC30 (43.0 offspring/female) of flonicamid, and at LC10 (42.1 offspring/female) of thiamethoxam than that of the control (29.5 offspring/female). Feeding behavior analysis using an electrical penetration graph showed that sublethal doses of flonicamid and thiamethoxam had significant effects on the duration of phloem ingestion. However, higher doses of flonicamid induced starvation by inhibition of phloem ingestion and higher doses of thiamethoxam induced contact toxicity rather than inhibition of feeding behavior. This study provides the basis for a more efficient use of these pesticides in Korea.

Effects of thiamethoxam on brain structure of Bombus terrestris (Hymenoptera: Apidae) workers

OPINION article Front. Physiol., 04 April 2013Sec. Invertebrate Physiology Volume 4 - 2013 | https://doi.org/10.3389/fphys.2013.00062

A sublethal dose of thiamethoxam causes a reduction in xylem feeding by the bird cherry-oat aphid ( Rhopalosiphum padi), which is associated with dehydration and reduced performance

Oral uptake of a glyphosate-based herbicide causes lethal and sublethal effects in two ant species

Bees are the important natural resources, play a crucial role in maintaining diversity and sustaining food security. In the past couple of years, these tiny animals are facing problems due to various factors like climate change, loss of habitat, loss of bee pasturage, reduced immunity, pesticide poisoning, etc. Among these, the insecticides, particularly the ones belonging to the class neonicotinoids have been blamed worldwide. Thiamethoxam is the one among various insecticides in this group. It is a systemic insecticide whose residues have been reported to contaminate the nectar and pollen. Since it has been classified as a highly toxic insecticide to bees, several cases of acute toxicity to adult bees have been reported. Besides this, sub-lethal doses have also been reported to cause negative effects on workers, queen bee, and drones. Some of the negative effects on important physiological or behavioral processes are reduced brood development, altered locomotion, incapability in maintaining thorax temperature, sensitivity to sucrose, effect on olfactory learning and foraging, etc. At the same time, the effects on the reproductive capacity of the colony due to the negative effects on queen bee and drone have also been observed. The work has also been carried out to find the basis, at the molecular level, governing such effects. Since there are several negative effects even due to the sub-lethal doses of thiamethoxam, it becomes imperative to sum up all the generated knowledge on this topic. Hence, the present review has been prepared which will provide critical information to the various stakeholders who may use the information to safeguard the bees/apiaries in a better way.

Discrimination behavior is a fundamental feature of social insects, and the discrimination ability allows the individual to be integrated into the colony. To address the brain functions associated with this task, which underlies intraspecific communication, I examined the ability to discriminate queens in young workers of the ant Camponotus japonicus together with a histological analysis of their brains. Workers raised in a foster colony were tested with respect to their ability to discriminate the foster queen from an unfamiliar queen. During the first 3 days after eclosing, some young workers made erroneous decisions whereas after 3–4 days the decisions were always correct. To assess brain maturation, mitotic activity in the brains of workers was individually analyzed using BrdU injection immediately after the behavioral test. Neurogenesis appeared to be complete at eclosion, but in 3 of 8 young workers that showed incorrect behavioral decisions, mitotic activity was observed in the antennal lobe. In contrast, no mitotic activity was observed in the brains of young workers who correctly discriminated their foster queens from alien queens. These results suggest that in newly emerged ant workers the ability to discriminate queens coincides with the completion of cell proliferation in the brain.

Exposure to neonicotinoid pesticides is considered one of the possible causes of honeybee (Apis mellifera) population decline. At sublethal doses, these chemicals have been shown to negatively affect a number of behaviours, including performance of olfactory learning and memory, due to their interference with acetylcholine signalling in the mushroom bodies. Here we provide evidence that neonicotinoids can affect odour coding upstream of the mushroom bodies, in the first odour processing centres of the honeybee brain, i.e. the antennal lobes (ALs). In particular, we investigated the effects of imidacloprid, the most common neonicotinoid, in the AL glomeruli via in vivo two-photon calcium imaging combined with pulsed odour stimulation. Following acute imidacloprid treatment, odour-evoked calcium response amplitude in single glomeruli decreases, and at the network level the representations of different odours are no longer separated. This demonstrates that, under neonicotinoid influence, olfactory information might reach the mushroom bodies in a form that is already incorrect. Thus, some of the impairments in olfactory learning and memory caused by neonicotinoids could, in fact, arise from the disruption in odor coding and olfactory discrimination ability of the honey bees.

RETURN TO ISSUEPREVNewsNEXTBee-Linked Pesticide Under FireCite this: Chem. Eng. News 2012, 90, 24, 9Publication Date (Print):June 11, 2012Publication History Published online29 March 2013Published inissue 11 June 2012https://pubs.acs.org/doi/10.1021/cen-09024-notw9https://doi.org/10.1021/cen-09024-notw9newsACS PublicationsCopyright © 2012 Chemical & Engineering NewsArticle Views16Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access options SUBJECTS:Agriculture,Coating materials,Crops,Redox reactions,Safety Get e-Alerts

Effects of Nosema ceranae and thiametoxam in Apis mellifera: A comparative study in Africanized and Carniolan honey bees.

Effect of Sub-Lethal Doses of Thiamethoxam on the Memory of <i>Apis mellifera</i> Linnaeus

The development of agricultural activities coincides with the increased use of pesticides to control pests, which can also be harmful to nontarget insects such as bees. Thus, the goal of this work was assess the toxic effects of thiamethoxam on newly emerged worker bees of Apis mellifera (africanized honeybee-AHB). Initially, we determined that the lethal concentration 50 (LC50 ) of thiamethoxam was 4.28 ng a.i./μL of diet. To determine the lethal time 50 (LT50 ), a survival assay was conducted using diets containing sublethal doses of thiamethoxam equal to 1/10 and 1/100 of the LC50. The group of bees exposed to 1/10 of the LC50 had a 41.2% reduction of lifespan. When AHB samples were analyzed by morphological technique we found the presence of condensed cells in the mushroom bodies and optical lobes in exposed honeybees. Through Xylidine Ponceau technique, we found cells which stained more intensely in groups exposed to thiamethoxam. The digestive and regenerative cells of the midgut from exposed bees also showed morphological and histochemical alterations, like cytoplasm vacuolization, increased apocrine secretion and increased cell elimination. Thus, intoxication with a sublethal doses of thiamethoxam can cause impairment in the brain and midgut of AHB and contribute to the honeybee lifespan reduction.

This project was designed to observe the hemato-biochemical effects of sub-lethal doses of thiamethoxam (TMX) in broiler chicks. A-day old chicks (n = 90) were procured from the local market and maintained under standard housing conditions and divided into five equal groups (18 birds/group). The experimental trial continued for 45 days. Sub-lethal doses of TMX including 50, 100, 200 and 400 mg/kg B.W. to groups A, B, C and D were administered through crop tube, respectively. Group E served as a control. Blood and serum samples were collected from each group on 10th, 17th, 24th, 31st, 38th and 45th day of the experiment. The data were analyzed through ANOVA by MSTAT-C. All hematological parameters were determined. Serum samples were analyzed for ALT, AST, total proteins and urea. It was concluded from this study that even sub-lethal doses of TMX have toxic effects on hematology and biochemical parameters.