Genetics, Synergists, and Age Affect Insecticide Sensitivity of the Honey Bee, Apis mellifera

Abstract

The number of honey bee colonies in the United States has declined to half of its peak level in the 1940s, and colonies lost over the winter have reached levels that are becoming economically unstable. While the causes of these losses are numerous and the interaction between them is very complex, the role of insecticides has garnered much attention. As a result, there is a need to better understand the risk of insecticides to bees, leading to more studies on both toxicity and exposure. While much research has been conducted on insecticides and bees, there have been very limited studies to elucidate the role that bee genotype and age has on the toxicity of these insecticides. The goal of this study was to determine if there are differences in insecticide sensitivity between honey bees of different genetic backgrounds (Carniolan, Italian, and Russian stocks) and assess if insecticide sensitivity varies with age. We found that Italian bees were the most sensitive of these stocks to insecticides, but variation was largely dependent on the class of insecticide tested. There were almost no differences in organophosphate bioassays between honey bee stocks (<1-fold), moderate differences in pyrethroid bioassays (1.5 to 3-fold), and dramatic differences in neonicotinoid bioassays (3.4 to 33.3-fold). Synergism bioassays with piperonyl butoxide, amitraz, and coumaphos showed increased phenothrin sensitivity in all stocks and also demonstrated further physiological differences between stocks. In addition, as bees aged, the sensitivity to phenothrin significantly decreased, but the sensitivity to naled significantly increased. These results demonstrate the variation arising from the genetic background and physiological transitions in honey bees as they age. This information can be used to determine risk assessment, as well as establishing baseline data for future comparisons to explain the variation in toxicity differences for honey bees reported in the literature.

Influence of Varroa Mite (Varroa destructor) Management Practices on Insecticide Sensitivity in the Honey Bee (Apis mellifera)

“…Decreased miticide sensitivity leads to over application of these miticides, resulting in high concentrations of these chemicals found in honey bee colonies [15]. Synergistic interactions between miticides and insecticides have been demonstrated [16,17], so their impact on colony health is of concern. Alternatively, Integrated Pest Management (IPM) strategies for Varroa mite can be implemented, which may include screened bottom boards [18], drone brood trapping [19], and grooming stimulation via powdered sugar application [20].…”

Extending standard testing period in honeybees to predict lifespan impacts of pesticides and heavy metals using dynamic energy budget modelling

“…used a commercial clothianidin formulation, whilst the active ingredient alone was used in this study29. It is also possible that colony specific differences in detoxification capacity influence these observed differences as well as other within-colony or inter-(sub) species variations in sensitivity1241. Indeed, a high sensitivity of A. mellifera spp.…”

Modulation of pesticide response in honeybees

“…One would thus expect that bees from different patrilines differ in their pesticide sensitivity or detoxification capacities, but this remains to be investigated. However, several studies indicate that the genetic background might influence the response to pesticides, given that the toxicity of a chemical varies between bees originating from different subspecies (Ladas 1972;Suchail et al 2000;Laurino et al 2013;Sandrock et al 2014;Rinkevich et al 2015) or colonies from the same strain (Tahori et al 1969;Smirle and Winston 1987). Indeed, one CYP450 gene was found to vary in expression between colonies originating from a hybrid population (A. m. mellifera /carnica ) (Derecka et al 2013).…”

“…It is therefore not surprising to observe age-dependent response to toxicants. For example, young bees were found to be more sensitive to some toxicants but less to others as compared to older bees (Mayland and Burkardt 1970;Ladas 1972;Bendahou et al 1997;Rinkevich et al 2015). Wahl and Ulm (1983) found an agerelated increase in sensitivity to an herbicide and fungicide, as well as a higher level of Nosema spore loads in old bees.…”