Abstract
Many environmental stressors are currently implicated in the decline of flying insects in general, and important pollinator species such as the honey bee. Recent studies have shown that extremely low frequency electromagnetic fields (ELF EMFs) affect many aspects of insect behaviour and cognition which raises the potential that ELF EMFs could interact with other environmental stressors such as neonicotinoid insecticides to have even greater impact on the decline of flying insects. Here we analysed the effects of individual and combined exposure of the honey bee to 50 Hz EMFs and sublethal exposure to clothianidin, in a tethered flight assay and an olfactory appetitive learning assay.Clothianidin was significantly toxic to bees and exposure to field-realistic levels (2.00 ng/bee) led to 25% mortality. Exposure to ELF EMFs alone led to a significant increase in wingbeat frequency at levels above 100 µT. Prior exposure to clothianidin attenuated the effects of EMFs on wingbeat frequency. Exposure to EMFs alone reduced learning of a proboscis extension reflex (PER). Prior exposure to low doses of clothianidin attenuated the effects of EMFs on PER.These results indicate no evidence of synergy between clothianidin and ELF EMFs as environmental stressors but suggest the potential for EMFs to affect the same susceptible fraction of the bee population that have been affected by clothianidin. Results lay the foundation to further explore the interactions of ELF EMFs with other environmental stressors and consider the key factors that may make bees susceptible to ELF EMFs.
Highlights
There is an inextricable link between environmental change from anthropogenic activities and adverse effects on ecosystems such as biodiversity loss (Butchart et al, 2010)
The current consensus is that this cocktail of human-derived environmental stressors/pollutants in combination is leading to declines in honey bees and other pollinators (Potts et al, 2010; Ollerton et al, 2014; Goulson et al, 2015a)
To determine the toxicity of clothianidin in bees we calculated dose-response curves for six clothianidin doses (0.25, 0.50, 1.00, 2.00, 4.00 and 10.00 ng/bee) and 24 hr mortality were plotted for each individual hive (Fig. 2A-C), and all hives combined (Fig. 2D)
Summary
There is an inextricable link between environmental change from anthropogenic activities and adverse effects on ecosystems such as biodiversity loss (Butchart et al, 2010). Neonicotinoids are systemic insecticides (Goulson, 2013; Bonmatin et al, 2015) that have a broad range of targets, and are used on a variety of crops (EFSA, 2013; Goulson, 2013) to control various sucking/biting pests (Elbert et al, 1998) Their use increased dramatically in the early 2000’s, with imidacloprid, clothianidin and thiamethoxam becoming the most commonly used neonicotinoids, largely due to their high toxicity (Goulson, 2013). The effects of neonicotinoids have been linked to reduced motor function in bees, leading to various behavioural alterations, including knockdown, poor coordination, increased locomotory activity and tremors (Lambin et al, 2001; Suchail et al, 2001; Medrzycki et al, 2003)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
