Field recommended concentrations of pyraclostrobin exposure disturb the development and immune response of worker bees (Apis mellifera L.) larvae and pupae

Abstract

The strobilurin fungicide pyraclostrobin is widely used to prevent and control the fungal diseases of various nectar and pollen plants. Honeybees also directly or indirectly contact this fungicide with a long-term exposure period. However, the effects of pyraclostrobin on the development and physiology of Apis mellifera larvae and pupae during continuous exposure have been rarely known. To investigate the effects of field-realistic concentrations of pyraclostrobin on honeybee survival and development, the 2-day-old larvae were continuously fed with different pyraclostrobin solutions (100 mg/L and 83.3 mg/L), and the expression of development-, nutrient-, and immune-related genes in larvae and pupae were examined. The results showed that two field-realistic concentrations of pyraclostrobin (100 and 83.3 mg/L) significantly decreased the survival and capped rate of larvae, the weight of pupae and newly emerged adults, and such decrease was a positive correlation to the treatment concentrations. qPCR results showed that pyraclostrobin could induce the expression of Usp, ILP2, Vg, Defensin1, and Hymenoptaecin, decrease the expression of Hex100, Apidaecin, and Abaecin in larvae, could increase the expression of Ecr, Usp, Hex70b, Vg, Apidaecin, and Hymenoptaecin, and decreased the expression of ILP1, Hex100 and Defensin1in pupae. These results reflect pyraclostrobin could decrease nutrient metabolism, immune competence and seriously affect the development of honeybees. It should be used cautiously in agricultural practices, especially in the process of bee pollination.

Glycolytic oscillations under periodic drivings

“…As long as the glucose is injected in a time-varying (periodic) manner over a proper range of frequency and amplitude, the system can be entrained into the Arnold tongues, still sustaining its oscillatory dynamics around its natural frequency. Although the role of glycolytic oscillations in physiology is not fully elucidated, glycolytic oscillations have been suggested as a pacemaker of other physiological oscillations [41][42][43]. Specifically, an oscillation of NADH, a product of glycolysis and the precursor of Kreb/electron transfer cycle, drives the oscillation of mitochondrial membrane potential [44].…”

“…1B), an increased glucose injection rate beyond ν 0 ≈ 0.01 mM/s (k = 0.05 s −1 ), which could potentially be associated with the hyperglycemia, would abolish the glycolytic oscillation. Although the role of glycolytic oscillations in physiology is not fully elucidated, glycolytic oscillations have been suggested as a pacemaker of other physiological oscillations [38][39][40]. Specifically, an oscillation of NADH, a product of glycolysis and the precursor of Kreb/electron transfer cycle, drives the oscillation of mitochondrial membrane potential [41].…”

Biodiversity and Challenges of Honey Bee Population in Pakistan

“…Wang et al [112] reported that the gut microbiota depletion using tetracycline aggravated MPs toxicity in the A. mellifera L. This antibiotic has also been reported to cause a reduction in the digestion of pollens in honey bees [121] and elevated mortality [122]. The antimicrobials also cause gut microbiota changes and other health effects in the larvae and pupae [120,123].…”

Ternary Mixture of Azoxystrobin, Boscalid and Pyraclostrobin Disrupts the Gut Microbiota and Metabolic Balance of Honeybees (Apis cerana cerana)

“…Pyraclostrobin-contaminated beebread could induce cytotoxicity in the cells of the midgut [ 19 ]. Chronic exposure to pyraclostrobin not only altered the midgut morphology and reduced polysaccharide labeling in foragers [ 20 ], it also impaired the development, nutrient metabolism and immunity of larvae and pupae [ 21 ]. In addition, the majority of fungicides are provided as formulations, such as the commercial fungicide Pristine ® , which consists of 25.2% boscalid and 12.8% pyraclostrobin and is produced by the BASF Corporation [ 22 ].…”