Thiamethoxam: Long-term effects following honey bee colony-level exposure and implications for risk assessment

Thompson, Helen; Overmyer, Jay P.; Feken, Max; Ruddle, Natalie; Vaughan, Sarah; Scorgie, Emily; Bocksch, Sigrun; Hill, Marcus

doi:10.1016/j.scitotenv.2018.11.003

Cited by 31 publications

(31 citation statements)

References 28 publications

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“…Colony overwinter survival and cluster size was significantly decreased by exposure to 100 ng/g of THI (Figures 2a and 3a). Our results agree with the colony-level feeding studies of Thompson et al (2019) [5] and Overmeyer et al (2018) [20], who found that colonies fed 100 ng/g of THI during six weeks in summer had significant (50%) reductions in number of adult bees relative to controls prior to overwintering and a significant, two times increase in overwinter mortality, but colonies fed lower doses of THI (12.5-50 ng/g THI) had no long-lasting colony effects.…”

Section: Effects Of Thiamethoxam On Overwintering Colonies Of Apis Mesupporting

confidence: 92%

“…As is typical of most colony-level studies, sample size was the greatest weakness of our field trial. While the number of colonies per treatment in F1 (twenty colonies) was larger than some overwinter studies [5], we still had inadequate statistical power to detect an effect at 20 ng/g of THI.…”

Section: Effects Of Thiamethoxam On Overwintering Colonies Of Apis Mementioning

confidence: 84%

“…A strength of our study design is that neonicotinoid exposure in our study occurred immediately prior to overwintering rather than during summer, as in other studies [5,20].…”

Section: Effects Of Thiamethoxam On Overwintering Colonies Of Apis Mementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Previous chronic colony-feeding studies [5], laboratory studies [6,7], and field trials [8] have examined the effects of THI or CLO exposure on overwinter survival of honey bees. A chronic, summer colony-feeding study [5] found significant decreases in overwinter survival with 100 ng/g THI exposure, and no significant effect of 12.5-50 ng/g THI exposure on overwintering. Interestingly, winter workers were more sensitive to chronic neonicotinoid exposure under laboratory conditions, with doses of 20 and 50 ng/g of CLO significantly reducing survival of winter adult workers and no effect of 1-10 ng/g of CLO on laboratory survival [6].…”

Section: Introductionmentioning

confidence: 99%

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Chronic High-Dose Neonicotinoid Exposure Decreases Overwinter Survival of Apis mellifera L.

Wood

Kozii

Mattos

et al. 2019

Insects

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Overwinter colony mortality is an ongoing challenge for North American beekeepers. During winter, honey bee colonies rely on stored honey and beebread, which is frequently contaminated with the neonicotinoid insecticides clothianidin and thiamethoxam. To determine whether neonicotinoid exposure affects overwinter survival of Apis mellifera L., we chronically exposed overwintering field colonies and winter workers in the laboratory to thiamethoxam or clothianidin at different concentrations and monitored survival and feed consumption. We also investigated the sublethal effects of chronic thiamethoxam exposure on colony pathogen load, queen quality, and colony temperature regulation. Under field conditions, high doses of thiamethoxam significantly increased overwinter mortality compared to controls, with field-realistic doses of thiamethoxam showing no significant effect on colony overwinter survival. Under laboratory conditions, chronic neonicotinoid exposure significantly decreased survival of winter workers relative to negative control at all doses tested. Chronic high-dose thiamethoxam exposure was not shown to impact pathogen load or queen quality, and field-realistic concentrations of thiamethoxam did not affect colony temperature homeostasis. Taken together, these results demonstrate that chronic environmental neonicotinoid exposure significantly decreases survival of winter workers in the laboratory, but only chronic high-dose thiamethoxam significantly decreases overwinter survival of colonies in the field.

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Section: Effects Of Thiamethoxam On Overwintering Colonies Of Apis Mesupporting

confidence: 92%

Section: Effects Of Thiamethoxam On Overwintering Colonies Of Apis Mementioning

confidence: 84%

“…A strength of our study design is that neonicotinoid exposure in our study occurred immediately prior to overwintering rather than during summer, as in other studies [5,20].…”

Section: Effects Of Thiamethoxam On Overwintering Colonies Of Apis Mementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Chronic High-Dose Neonicotinoid Exposure Decreases Overwinter Survival of Apis mellifera L.

Wood

Kozii

Mattos

et al. 2019

Insects

View full text Add to dashboard Cite

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Simulating Honey Bee Large‐Scale Colony Feeding Studies Using the BEEHAVE Model—Part I: Model Validation

Schmolke

Abi‐Akar

Roy

et al. 2020

Enviro Toxic and Chemistry

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In pesticide risk assessments, semifield studies, such as large-scale colony feeding studies (LSCFSs), are conducted to assess potential risks at the honey bee colony level. However, such studies are very cost and time intensive, and high overwintering losses of untreated control hives have been observed in some studies. Honey bee colony models such as BEEHAVE may provide tools to systematically assess multiple factors influencing colony outcomes, to inform study design, and to estimate pesticide impacts under varying environmental conditions. Before they can be used reliably, models should be validated to demonstrate they can appropriately reproduce patterns observed in the field. Despite the recognized need for validation, methodologies to be used in the context of applied ecological models are not agreed on. For the parameterization, calibration, and validation of BEEHAVE, we used control data from multiple LSCFSs. We conducted detailed visual and quantitative performance analyses as a demonstration of validation methodologies. The BEEHAVE outputs showed good agreement with apiary-specific validation data sets representing the first year of the studies. However, the simulations of colony dynamics in the spring periods following overwintering were identified as less reliable. The comprehensive validation effort applied provides important insights that can inform the usability of BEEHAVE in applications related to higher tier risk assessments. In addition, the validation methodology applied could be used in a wider context of ecological models.

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Simulating Honey Bee Large‐Scale Colony Feeding Studies Using the BEEHAVE Model—Part II: Analysis of Overwintering Outcomes

Abi‐Akar

Schmolke

Roy

et al. 2020

Enviro Toxic and Chemistry

View full text Add to dashboard Cite

Large-scale colony feeding studies (LSCFSs) aim to assess potential pesticide exposure to and effects on honey bees at the colony level. However, these studies are sometimes affected by high losses of control colonies, indicating that other stressors may impact colonies and confound the analysis of potential pesticide impacts. We assessed the study design and environmental conditions experienced by the untreated control colonies across 7 LSCFSs conducted in North Carolina (USA). Overwintering success differed considerably among the studies, as did their initial colony conditions, amount and timing of sugar feeding, landscape composition, and weather. To assess the effects of these drivers on control colonies' overwintering success, we applied the mechanistic colony model BEEHAVE. Sugar feedings and initial status of the simulated colonies were more important for fall colony condition than were landscape and weather. Colonies that had larger colony sizes and honey stores in the fall were those that began with larger honey stores, were provided more sugar, and had supplemental feedings before the fall. This information can be used to inform the standardization of a study design, which can increase the likelihood of overwintering survival of controls and help ensure that LSCFSs are comparable. Our study demonstrates how a mechanistic model can be used to inform study designs for higher tier effects studies.

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Thiamethoxam: Long-term effects following honey bee colony-level exposure and implications for risk assessment

Cited by 31 publications

References 28 publications

Chronic High-Dose Neonicotinoid Exposure Decreases Overwinter Survival of Apis mellifera L.

Chronic High-Dose Neonicotinoid Exposure Decreases Overwinter Survival of Apis mellifera L.

Simulating Honey Bee Large‐Scale Colony Feeding Studies Using the BEEHAVE Model—Part I: Model Validation

Simulating Honey Bee Large‐Scale Colony Feeding Studies Using the BEEHAVE Model—Part II: Analysis of Overwintering Outcomes

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