Exposure of honey bee colonies to simulated RF-EMF: Negative effects on homing ability

Abstract

Exposure of honey bee colonies to simulated RF-EMF: Negative effects on homing ability Treder M, Müller M, Fellner L, Traynor K, Rosenkranz P. Defined exposure of honey bee colonies to simulated radiofrequency electromagnetic fields (RF-EMF): Negative effects on the homing ability, but not on brood development or longevity. Sci Total Environ. 2023 Jun 28:165211. doi: 10.1016/j.scitotenv.2023.165211. Highlights • RF-EMF exposure significantly reduced homing success of honey bees. • These effects on homing behavior were only evident after long-term, not short-term, irradiation • Honey bee brood development and longevity was not affected by RF-EMF. Abstract Urbanization and the increasing use of wireless technologies lead to higher emission rates of radiofrequency electromagnetic fields (RF-EMF) in populated areas. This anthropogenic electromagnetic radiation is a form of environmental pollution and a potential stressor on bees or other flying insects. Cities often have a high density of wireless devices operating on microwave frequencies, which generate electromagnetic frequencies e.g. in the 2.4 and 5.8 GHz bands commonly used by the wireless technologies. To date the effects of nonionizing electromagnetic radiation on the vitality and behavior of insects are poorly understood. In our experiment we used honey bees as model organisms and analyzed the effects of defined exposures to 2.4 and 5.8 GHz on brood development, longevity and homing ability under field conditions. To generate this radiation, we used a high- quality radiation source which generates a consistent, definable and realistic electromagnetic radiation, engineered for this experiment by the Communications Engineering Lab (CEL) at the Karlsruhe Institute of Technology. Our results show significant effects of long-term exposures on the homing ability of foraging honey bees, but no effects on brood development and adult worker longevity. Using this novel and high-quality technical set-up, this interdisciplinary work provides new data on the effects of these widely used frequencies on important fitness parameters of free-flying honey bees. pubmed.ncbi.nlm.nih.gov Excerpts "We investigated the impacts on homing ability by transporting bees 500 meters away from their colonies, then comparing the number of successful return flights of treated and control bees. Long-term RF-EMF exposure had a clear negative impact on the orientation ability of foraging honey bees (GLMM, p = 0.0064). The number of bees that successfully found their way back to their hives differed significantly, with 95.2 % of the bees in the control group returning home successfully compared to only 78.6 % of the bees in the treatment group. The long-term treated bees also required approximately 20 % more time on their return homing flights compared to the controls (median: EMF 9:58 min vs. Control 8:14 min), however these differences were not significant (GLMM, p = 0.4508)." "Conclusion The complex effects of radiofrequency electromagnetic fields (RF-EMF) on insects needs increased attention. Our results suggest that there are no lethal or highly obvious impacts on honey bee health, however RF-EMF acts as a sublethal stressor, reducing the homing success of honey bees and thus generating a loss of foragers. This disorientation only occurs in colonies continuously exposed to the tested and field realistic RF-EMF, a signal commonly used for Wi-Fi. RF-EMF did not impact other important fitness parameters, such as the overall development of healthy brood or longevity. Due to their different nesting habitats and degrees of sociality, wild bees may be more susceptible to negative effects of electromagnetic radiation. These knowledge gaps must be urgently addressed, as many wild bee species are threatened by extinction. In our globalized and interconnected world, few environments are free of electromagnetic radiation. A better understanding of the sublethal effects of electromagnetic radiation exposure on communication, learning, memory, and development of bees and insects are urgently needed."

AI evidence extraction

Main findings

Defined exposure to simulated RF-EMF at 2.4 and 5.8 GHz under field conditions significantly reduced homing success of foraging honey bees after long-term (but not short-term) exposure. Brood development and adult worker longevity were not affected; homing flight time was ~20% longer in exposed bees but not statistically significant.

Outcomes measured

• Homing success (return flights after displacement)
• Homing flight time
• Brood development
• Adult worker longevity

Limitations

• Sample size not reported in provided text
• Exposure metrics such as SAR or field strength not reported in provided text
• Details of exposure duration definitions (short-term vs long-term) not fully specified in provided text

Suggested hubs

• school-wi-fi (0.55)
  Exposure described as a signal commonly used for Wi‑Fi (2.4 and 5.8 GHz).

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        "frequency_mhz": null,
        "sar_wkg": null,
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    "population": "Honey bee colonies / foraging honey bees (field conditions)",
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    "main_findings": "Defined exposure to simulated RF-EMF at 2.4 and 5.8 GHz under field conditions significantly reduced homing success of foraging honey bees after long-term (but not short-term) exposure. Brood development and adult worker longevity were not affected; homing flight time was ~20% longer in exposed bees but not statistically significant.",
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