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

Abstract

Overview

Honeybee and general pollinator decline is widely recognized across the globe, raising serious concerns about biodiversity loss. Numerous studies have been conducted to identify the reasons behind this decline, with multi-stress factors frequently cited as the most likely culprits.

Research Focus

This study specifically investigates the combined impacts of two stress factors on bees: pesticides and electromagnetic fields. The research was conducted over a one-year period from April 2017 to April 2018 using three experimental sites: a control site, a pesticide-stressed site, and a site exposed to both pesticides and electromagnetic fields from a nearby high-voltage electric line.

• Weekly observations included colony survival, queen activity, storage and brood volumes, as well as parasite and pathogen levels.
• Biomarkers in young workers and pupae were analyzed, including acetylcholinesterase, catalase, glutathione S-transferase, alkaline phosphatase, and Reactive Oxygen Species.
• DNA fragmentation and lipid peroxidation were examined as effect biomarkers.

Findings

The multi-stress site showed a significant degradation in bee health, with only one colony remaining alive out of the initial four. Detailed observations revealed:

• The appearance of diseases such as American foulbrood.
• Increase in mortality rates compared to the pesticide-only site.
• Behavioral changes like frequent queen replacements and excessive honey storage.
• Elevated levels of alkaline phosphatase by season's end indicating severe physiological stress.

Conclusion

The study’s results clearly demonstrate that exposure to both pesticides and electromagnetic fields greatly exacerbates the threats to bee colonies, leading to significant biochemical, physiological, and behavioral changes that imperil their survival.