Journal Article•
Potential routes of exposure as a foundation for a risk assessment scheme: a Conceptual Model
TL;DR: The quantitative pollinator conceptual model (QPCM) describes the flow pathways and potential exposure routes for honeybees and other bee pollinators in sufficient detail to support quantitative exposure modelling and risk assessment and shows the importance of measuring the distribution of pesticide residues in the areas that lead to exposure and in the hive.
Abstract: Background: The global interest in improving the regulatory risk assessment of pesticides in honeybees and other pollinator insects has led to new test requirements and a conceptual model has been published in the US. It is of interest for modellers and risk assessors to have a more detailed conceptual model that describes the movement of deleterious substances from the point of initial exposure to the point of impact on the protection goals, such as colony health, or honey production. Results: The flow of pesticide residues from application to distribution in the hive is described in an integrated conceptual model. The significance of this model for assessing the relative contribution of various potential routes of exposure, guiding test requirements and describing the quantitative distribution of residues among the castes and task groups of honeybees in the colony was described using data from studies with chlorpyrifos and several neonicotinoids. Conclusion: The quantitative pollinator conceptual model (QPCM) describes the flow pathways and potential exposure routes for honeybees and other bee pollinators in sufficient detail to support quantitative exposure modelling and risk assessment and shows the importance of measuring the distribution of pesticide residues in the areas that lead to exposure and in the hive.
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213 citations
TL;DR: It is submitted that 2 key processes underlie honey bee pesticide exposure: 1) the acquisition of pesticide by foraging bees, and 2) the in‐hive distribution of pesticide returned by foragers.
Abstract: The role of pesticides in recent honey bee losses is controversial, partly because field studies often fail to detect effects predicted by laboratory studies. This dissonance highlights a critical gap in the field of honey bee toxicology: there exists little mechanistic understanding of the patterns and processes of exposure that link honey bees to pesticides in their environment. The authors submit that 2 key processes underlie honey bee pesticide exposure: 1) the acquisition of pesticide by foraging bees, and 2) the in-hive distribution of pesticide returned by foragers. The acquisition of pesticide by foraging bees must be understood as the spatiotemporal intersection between environmental contamination and honey bee foraging activity. This implies that exposure is distributional, not discrete, and that a subset of foragers may acquire harmful doses of pesticide while the mean colony exposure would appear safe. The in-hive distribution of pesticide is a complex process driven principally by food transfer interactions between colony members, and this process differs importantly between pollen and nectar. High priority should be placed on applying the extensive literature on honey bee biology to the development of more rigorously mechanistic models of honey bee pesticide exposure. In combination with mechanistic effects modeling, mechanistic exposure modeling has the potential to integrate the field of honey bee toxicology, advancing both risk assessment and basic research. Environ Toxicol Chem 2017;36:871-881. © 2016 SETAC.
54 citations
TL;DR: How certain pesticide risks are particularly important under circumstances related to the cavity nesters is highlighted, incorporating the relative importance of environmental contamination due to pesticide chemical behaviors.
Abstract: Abstract Declines of pollinator health and their populations continue to be commercial and ecological concerns. Agricultural practices, such as the use of agrochemicals, are among factors attributed to honey bee (Apis mellifera L. (Hymenoptera: Apidae)) population losses and are also known to have negative effects on populations of managed non-Apis pollinators. Although pesticide registration routinely requires evaluation of impacts on honey bees, studies of this social species may not reveal important pesticide exposure routes where managed, solitary bees are commonly used. Studies of solitary bees offer additional bee models that are practical from the aspect of availability, known rearing protocols, and the ability to assess effects at the individual level without confounding factors associated with colony living. In addition to understanding bees, it is further important to understand how pesticide characteristics determine their environmental whereabouts and persistence. Considering our research expertise in advancing the management of solitary bees for crop pollination, this forum focuses on routes of pesticide exposure experienced by cavity-nesting bees, incorporating the relative importance of environmental contamination due to pesticide chemical behaviors. Exposure routes described are larval ingestion, adult ingestion, contact, and transovarial transmission. Published research reports of effects of several pesticides on solitary bees are reviewed to exemplify each exposure route. We highlight how certain pesticide risks are particularly important under circumstances related to the cavity nesters.
46 citations
Cites background from "Potential routes of exposure as a f..."
...2014, Purdy 2014, USEPA, PMRA, and CDPR 2014, Heard et al....
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TL;DR: It is suggested that the analysis of pesticides in bee bread and in bees from the brood comb is a useful addition to dead bee and suspected crop analysis in poisoning incidents to inform the extent of recent in-hive contamination.
18 citations
TL;DR: In this article , the sub-lethal effects of MEOF-contaminated pollen and queen cell wax on replacement queen development were examined, and the results showed that exposed colonies were largely able to produce replacement queens of similar physiological and reproductive quality as unexposed colonies.
Abstract: Abstract Honey bees are incidentally exposed to pesticides such as the insect growth regulator methoxyfenozide (MEOF) during crop pollination, exposures that extend into the hive via contaminated stored food. We examined the sublethal effects of MEOF-contaminated pollen and queen cell wax on replacement queen development. MEOF-exposed colonies were largely able to produce replacement queens of similar physiological and reproductive quality as unexposed colonies. Newly established queens did not differ in their body mass, ovariole development, or protein and fatty acid contents in their ovaries and fat bodies. MEOF and control queens had similar glandular contents of queen mandibular pheromone (QMP) and queen retinue pheromone (QRP) compounds. However, MEOF queens stored less sperm in their spermathecae than control queens. Given that queen productivity is ultimately limited by sperm availability, MEOF contamination might shorten the functional lifespan of exposed queens.
1 citations
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TL;DR: How neonicotinoids interact with the nervous system of honeybees and affect individual honeybees in laboratory situations is described and a review of current and proposed guidance in the United States and Europe for assessing the risks of pesticides to honeybees is concluded.
Abstract: The European honeybee, Apis mellifera, is an important pollinator of agricultural crops. Since 2006, when unexpectedly high colony losses were first reported, articles have proliferated in the popular press suggesting a range of possible causes and raising alarm over the general decline of bees. Suggested causes include pesticides, genetically modified crops, habitat fragmentation, and introduced diseases and parasites. Scientists have concluded that multiple factors in various combinations—including mites, fungi, viruses, and pesticides, as well as other factors such as reduction in forage, poor nutrition, and queen failure—are the most probable cause of elevated colony loss rates. Investigators and regulators continue to focus on the possible role that insecticides, particularly the neonicotinoids, may play in honeybee health. Neonicotinoid insecticides are insect neurotoxicants with desirable features such as broad-spectrum activity, low application rates, low mammalian toxicity, upward systemic movement in plants, and versatile application methods. Their distribution throughout the plant, including pollen, nectar, and guttation fluids, poses particular concern for exposure to pollinators. The authors describe how neonicotinoids interact with the nervous system of honeybees and affect individual honeybees in laboratory situations. Because honeybees are social insects, colony effects in semifield and field studies are discussed. The authors conclude with a review of current and proposed guidance in the United States and Europe for assessing the risks of pesticides to honeybees.
214 citations
"Potential routes of exposure as a f..." refers background in this paper
...(9-11) According to Bailey and Ball “Viruses have probably always been prime sources of confusion and error in the diagnosis and management of bee diseases”....
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213 citations
"Potential routes of exposure as a f..." refers background in this paper
...(12) This is of particular significance now, since virus and other disease symptoms are being promoted as neonicotinoid toxicity effects....
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TL;DR: The PPR Panel was asked to deliver a scientific opinion on the science behind the development of a risk assessment of plant protection products on bees and proposals for separate risk assessment schemes, one for honey bees and one for bumble bees and solitary bees, were developed.
Abstract: The PPR Panel was asked to deliver a scientific opinion on the science behind the development of a risk assessment of plant protection products on bees (Apis mellifera, Bombus spp. and solitary bees). Specific protection goals options were suggested based on the ecosystem services approach. The different routes of exposure were analysed in detail for different categories of bees. The existing test guidelines were evaluated and suggestions for improvement and further research needs were listed. A simple prioritisation tool to assess cumulative effects of single pesticides using mortality data is suggested. Effects from repeated and simultanous exposure and synergism are discussed. Proposals for separate risk assessment schemes, one for honey bees and one for bumble bees and solitary bees, were developed.
175 citations
01 Jan 2016
TL;DR: The concepts of life history and life history traits, fitness, and an overview of analytical tools that are commonly used in life history studies are introduced.
Abstract: Life history theory attempts to explain the diversity of life history patterns, and the mechanisms by which natural selection has shaped life-history traits. It attempts to answer questions such as why organisms are large or small, why they grow fast or slowly, why they mature early or late, why they produce one or many offspring, and why they reproduce once or many times during their lives. In this article, we introduce the concepts of life history and life history traits, fitness, and provide an overview of analytical tools that are commonly used in life history studies.
158 citations
"Potential routes of exposure as a f..." refers background in this paper
...24 Julius-Kühn-Archiv, 450, 2015 various tasks as needed.(7) Newly emerged bees clean the hive and cap cells, then progress to caring for the brood and queen, followed by comb building, grooming and food handling....
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...(7) The conflicting protection goals are discussed further below but the key consideration for risk assessment is that the unit of replication for honeybee risk assessment is the colony....
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01 Jan 2010
TL;DR: As the bee group is the most important pollinator worldwide, this bulletin focuses on the instability of wild and managed bee populations, the driving forces, potential mitigating measures and recommendations.
Abstract: Current evidence demonstrates that a sixth major extinction of biological diversity event is underway.1. The Earth is losing between one and ten percent of biodiversity per decade2, mostly due to habitat loss, pest invasion, pollution, over-harvesting and disease3. Certain natural ecosystem services are vital for human societies. Many fruit, nut, vegetable, legume, and seed crops depend on pollination. Pollination services are provided both by wild, free-living organisms (mainly bees, but also to name a few many butterflies, moths and flies), and by commercially managed bee species. Bees are the predominant and most economically important group of pollinators in most geographical regions. The Food and Agriculture Organisation of the United Nations (FAO)4 estimates that out of some 100 crop species which provide 90% of food worldwide, 71 of these are bee-pollinated. In Europe alone, 84% of the 264 crop species are animal- pollinated and 4 000 vegetable varieties exist thanks to pollination by bees5. The production value of one tonne of pollinator-dependent crop is approximately five times higher than one of those crop categories that do not depend on insects6. Has a “pollinator crisis” really been occurring during recent decades, or are these concerns just another sign of global biodiversity decline? Several studies have highlighted different factors leading to the pollinators' decline that have been observed around the world. This bulletin considers the latest scientific findings and analyses possible answers to this question. As the bee group is the most important pollinator worldwide, this bulletin focuses on the instability of wild and managed bee populations, the driving forces, potential mitigating measures and recommendations.
114 citations
"Potential routes of exposure as a f..." refers background in this paper
...(9-11) According to Bailey and Ball “Viruses have probably always been prime sources of confusion and error in the diagnosis and management of bee diseases”....
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