Combined Effects of Pesticides and Electromagnetic-Fields on Honeybees: Multi-Stress Exposure

Abstract

Honeybee and general pollinator decline is extensively reported in many countries, adding new concern to the general biodiversity loss. Many studies were addressed to assess the causes of pollinator decline, concluding that in most cases multi-stress effects were the most probable ones. In this research, the combined effects of two possible stress sources for bees, pesticides and electromagnetic fields (multi-stress conditions), were analyzed in the field. Three experimental sites were chosen: a control one far from direct anthropogenic stress sources, a pesticide-stress site and multi-stress one, adding to the same exposure to pesticides the presence of an electromagnetic field, coming from a high-voltage electric line. Experimental apiaries were monitored weekly for one year (from April 2017 to April 2018) by means of colony survival, queen activity, storage and brood amount, parasites and pathogens, and several biomarkers in young workers and pupae. Both exposure and effect biomarkers were analysed: among the first, acetylcholinesterase (AChE), catalase (CAT), glutathione S-transferase (GST) and alkaline phosphatase (ALP) and Reactive Oxygen Species (ROS); and among the last, DNA fragmentation (DNAFRAGM) and lipid peroxidation (LPO). Results showed that bee health conditions were the worst in the multi-stress site with only one colony alive out of the four ones present at the beginning. In this site, a complex picture of adverse effects was observed, such as disease appearance (American foulbrood), higher mortality in the underbaskets (common to pesticide-stress site), behavioral alterations (queen changes, excess of honey storage) and biochemical anomalies (higher ALP activity at the end of the season). The overall results clearly indicate that the multi-stress conditions were able to induce biochemical, physiological and behavioral alterations which severely threatened bee colony survival.

Effects of Artificial Electromagnetic Fields on Bees: A Global Review

“…Keywords clusters "honeybee", "animals", "Apis mellifera", "apoideos" are mostly related to the number of studies that were published in the past 12 years (2010-2022), because there is special interest on preserving bees and because of major efforts to understand the cause of beesʼ behavior 84 .…”

Biological Effects of Electric, Magnetic, and Electromagnetic Fields from 0 to 100 MHz on Fauna and Flora: Workshop Report

“…On the other hand, field investigations (Lupi et al 2020(Lupi et al , 2021 have shown negative effects of electric and magnetic fields from power lines in combination with pesticides on various biomarkers of bee health, separately as well as in combination. The strongest negative effects on vital parameters were observed in combined multistress situations.…”

Colony collapse disorder: A peril to apiculture

“…From the study by Wyszkowska et al (2019), it is evident that upon exposure of honey bees (A. mellifera carnica F.) to 50 Hz ELF-EMF at 1mT and 7mT, induced a negative influence on the foraging and migratory behaviour of the bees. Thus, ELF-EMF can be accounted as a biological stressor affecting their orientation and motor skills, finally reducing the capability of crop pollination (Lupi et al, 2021).…”