Formetanate toxicity and changes in antioxidant enzyme system of Apis mellifera larvae

Abstract

Substantial percentage of world food production depends on pollinating service of honeybees that directly depends on their health status. Among other factors, the success of bee colonies depends on health of developed larvae. The crucial phase of larval development is the first 6 days after hatching when a worker larva grows exponentially and larvae are potentially exposed to xenobiotics via diet. In the present study, we determined the lethal concentration LC (72 h) following single dietary exposure of honeybee larvae to formetanate under laboratory conditions, being also the first report available in scientific literature. Activities of antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) were also measured in the homogenates of in vitro reared honeybee larvae after single formetanate exposure. Decreased specific activity of SOD and increased activities of CAT and GST suggest the induction of oxidative stress. Higher levels of thiobarbituric reactive species in all samples supported this fact. Comparing determined larval toxicity (LC of 206.01 mg a.i./kg diet) with adult toxicity data, we can suppose that the larvae may be less sensitive to formetanate than the adult bees.

Acute toxicity of five pesticides to Apis mellifera larvae reared in vitro

“…This finding is in line with results that larvae were more tolerant to imidacloprid than adult honey bees. 46 Similarly, larvae were more tolerant to thiamethoxam 47 and formetanate 48 compared with adult honey bees. Different sensitivity between larvae and adults can be explained by the presence of the insect fat body which plays major role in intermediary metabolism.…”

“…Different sensitivity between larvae and adults can be explained by the presence of the insect fat body which plays major role in intermediary metabolism. 48 Chlorpyrifos is not used in apiculture, but this highly toxic organophosphate is one of the most ubiquitous chemicals found in hive matrices like honey bee wax, pollen and adult honey bees. 4,49,50 Chlorpyrifos is of high acute toxicity (LD 50 = 0.06-0.11 μg/bee) to honey bee adults.…”

Effect of Sublethal Doses of Imidacloprid on the Biological Performance of Aphid Endoparasitoid Aphidius gifuensis (Hymenoptera: Aphidiidae) and Influence on Its Related Gene Expression

“…In the eastern honey bee Apis cerana cerana , the sigma-class AccGSTS1 was up-regulated by phoxim, cyhalothrin and acaricide and the theta-class GST gene GSTT1 and omega-class GST gene GSTO2 was induced by cyhalothrin, phoxim, pyridaben, and paraquat, indicating that they might be involved in the stress response to pesticides (Yan et al, 2013; Zhang et al, 2013; Liu S. et al, 2016). Furthermore, formetanate increased the activity of GST, whereas IMD and dimethoate had no influence on GST activity in A. mellifera (Li Z. et al, 2017; Staron et al, 2017). However, in this work, only one GST (Cluster-9767.30914) was found to be highly expressed in the IMD treated A. gifuensis compared to the CK treatment, while the rest of the GSTs did not show any response to sublethal doses of IMD treatment.…”

Chronic toxicity of clothianidin, imidacloprid, chlorpyrifos, and dimethoate to Apis mellifera L. larvae reared in vitro

“…To date, only a few studies have been conducted to assess the effect of pesticides on honey bee larvae. [43][44][45][46] Chronic exposure to pesticides impact the survival and development of bee brood. 47 Conceivably, impacts on the larval phase could lead to weakening of the colony structure over time.…”