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Abstract
The allometric scaling of metabolic rate and what drives it are major questions in biology with a long history. Since the metabolic rate at any level of biological organization is an emergent property of its lower-level constituents, it is an outcome of the intrinsic heterogeneity among these units and the interactions among them. However, the influence of lower-level heterogeneity on system-level metabolic rate is difficult to investigate, given the tightly integrated body plan of unitary organisms. In this context, social insects such as honeybees can serve as important model systems because unlike unitary organisms, these superorganisms can be taken apart and reassembled in different configurations to study metabolic rate and its various drivers at different levels of organization. This commentary discusses the background of such an approach and how combining it with artificial selection to generate heterogeneity in metabolic rate with an analytical framework to parse out the different mechanisms that contribute to the effects of heterogeneity can contribute to the various models of metabolic scaling. Finally, the absence of the typical allometric scaling relationship among different species of honeybees is discussed as an important prospect for deciphering the role of top-down ecological factors on metabolic scaling. This article is part of the theme issue 'The evolutionary significance of variation in metabolic rates'.
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Affiliation(s)
- Dhruba Naug
- Department of Biology, Colorado State University, 1878 Campus Delivery, Fort Collins, CO 80523, USA
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2
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Murcia-Morales M, Vejsnæs F, Brodschneider R, Hatjina F, Van der Steen JJM, Oller-Serrano JL, Fernández-Alba AR. Enhancing the environmental monitoring of pesticide residues through Apis mellifera colonies: Honey bees versus passive sampling. Sci Total Environ 2023; 884:163847. [PMID: 37127158 DOI: 10.1016/j.scitotenv.2023.163847] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 04/26/2023] [Accepted: 04/26/2023] [Indexed: 05/03/2023]
Abstract
The use of apicultural matrices for the environmental monitoring of pesticides is a widely employed approach that facilitates to a great extent the sampling procedures. Honey bees are one of the most commonly employed matrices in these studies due to their abundance in the colonies and their direct contact with the beehive and the environment. However, the analysis of this matrix is associated to a lack of representativity of the contaminants accumulated within the beehive, due mainly to the limited number of honey bees that are sampled and analyzed compared to the population in a hive. This small proportion of organisms which are sampled from the colony may lead to underestimations or overestimations of the total pesticide load, depending on the specific individuals that are included in the analysis. In the present work, the passive, non-invasive APIStrip-based sampling approach is compared to active bee sampling with a total of 240 samples taken from 15 apiaries from Austria, Denmark and Greece over a two-month period in 2022. The APIStrips have been found to provide a more comprehensive image of the pesticide residues accumulated in the beehive in terms of number of identified residues and robustness of the results. A total of 74 different pesticide residues were detected: the use of APIStrips allowed to detect 66 pesticides in the three countries, compared to 38 residues in honey bees. The use of APIStrips also resulted in a higher percentage of positive samples (containing at least one pesticide residue). The results provided by the passive sampling approach were also more consistent among the replicates and over time, which reveals an increased sampling robustness.
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Affiliation(s)
- María Murcia-Morales
- Chemistry and Physics Department, University of Almeria, Agrifood Campus of International Excellence (ceiA3), 04120 Almería, Spain
| | | | - Robert Brodschneider
- Institute of Biology, University of Graz, Universitätsplatz 2, Graz 8010, Austria
| | - Fani Hatjina
- Department of Apiculture, Institute of Animal Science, Ellinikos Georgikos Organismos 'DIMITRA', Nea Moudania GR-63200, Greece
| | | | - José Luis Oller-Serrano
- Chemistry and Physics Department, University of Almeria, Agrifood Campus of International Excellence (ceiA3), 04120 Almería, Spain
| | - Amadeo R Fernández-Alba
- Chemistry and Physics Department, University of Almeria, Agrifood Campus of International Excellence (ceiA3), 04120 Almería, Spain.
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Abay Z, Bezabeh A, Gela A, Tassew A. Evaluating the Impact of Commonly Used Pesticides on Honeybees (Apis mellifera) in North Gonder of Amhara Region, Ethiopia. J Toxicol 2023; 2023:2634158. [PMID: 37034150 PMCID: PMC10081893 DOI: 10.1155/2023/2634158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 03/09/2023] [Accepted: 03/15/2023] [Indexed: 04/03/2023] Open
Abstract
Global honeybee losses and colony decline are becoming continuous threat to the apicultural industry, as well as, for food security and environmental stability. Although the putative causes are still unclear, extensive exposure of bees to pesticides could be the possible factor for worldwide colony losses. This study was aimed at evaluating the impact of nine commonly used pesticide incidents on adult worker honeybees (A. mellifera) under the laboratory condition, in North Gonder of Amhara region, Ethiopia. Feeding test, contact test, and fumigation tests were carried out for each pesticide following the standard procedures, and each pesticide toxicity was compared to the standard toxic chemical, dimethoate 40% EC (positive control), and to 50% honey solution (negative control). The results revealed that all the tested pesticides caused significant deaths of the experimental bees (
) in all the tests when compared to the negative control. Diazinon 60% EC, endosulfan 35% EC, and malathion 50% EC were appeared highly toxic causing 100% mortality of bees, while chlorsulfuron 75% WG killed 90% of the experimental bees as tested via feeding. On the other hand, agro-2, 4-D and its mixture with glycel 41% EC are moderately toxic, and mancozeb 80% WP and glycel 41% EC were slightly toxic to honeybees as compared to the positive control (dimethoate 40% EC). Suddenly, diazinon 60% EC and malathion 50% EC triggered 100% mortality of bees, while endosulfan 35% EC and chlorsulfuron 75% WG caused 63.63% and 90.82% of bee mortality, respectively, when evaluated via contact test. The fumigation test also showed that chlorsulfuron 75% WG, diazinon 60% EC, and endosulfan 35% EC caused 100%, 86.7%, and 65.6% mortality rate of bees. Our result also highlighted that tested LD50 of all pesticide incidents were significantly lower than the manufacturer-based LD50. This shows that local honeybees A. m. jemenetica are extremely sensitive to commonly used agricultural pesticides, which may affect the colony level due to the intensive application of these pesticides in Ethiopia.
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Barascou L, Sene D, Le Conte Y, Alaux C. Pesticide risk assessment: honeybee workers are not all equal regarding the risk posed by exposure to pesticides. Environ Sci Pollut Res Int 2022; 29:90328-90337. [PMID: 35864404 DOI: 10.1007/s11356-022-21969-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 07/07/2022] [Indexed: 06/15/2023]
Abstract
Toxicological studies in honeybees have long shown that a single pesticide dose or concentration does not necessarily induce a single response. Inter-individual differences in pesticide sensitivity and/or the level of exposure (e.g., ingestion of pesticide-contaminated matrices) may explain this variability in risk posed by a pesticide. Therefore, to better inform pesticide risk assessment for honeybees, we studied the risk posed by pesticides to two behavioral castes, nurse, and forager bees, which are largely represented within colonies and which exhibit large differences in their physiological backgrounds. For that purpose, we determined the sensitivity of nurses and foragers to azoxystrobin (fungicide) and sulfoxaflor (insecticide) upon acute or chronic exposure. Azoxystrobin was found to be weakly toxic to both types of bees. However, foragers were more sensitive to sulfoxaflor than nurses upon acute and chronic exposure. This phenomenon was not explained by better sulfoxaflor metabolization in nurses, but rather by differences in body weight (nurses being 1.6 times heavier than foragers). Foragers consistently consumed more sugar syrup than nurses, and this increased consumption was even more pronounced with pesticide-contaminated syrup (at specific concentrations). Altogether, the stronger susceptibility and exposure of foragers to sulfoxaflor contributed to increases of 2 and tenfold for the acute and chronic risk quotients, respectively, compared to nurses. In conclusion, to increase the safety margin and avoid an under-estimation of the risk posed by insecticides to honeybees, we recommend systematically including forager bees in regulatory tests.
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Affiliation(s)
| | - Deborah Sene
- INRAE, Abeilles Et Environnement, Avignon, France
| | | | - Cedric Alaux
- INRAE, Abeilles Et Environnement, Avignon, France.
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Gregory CL, Fell RD, Belden LK, Walke JB. Classic Hoarding Cages Increase Gut Bacterial Abundance and Reduce the Individual Immune Response of Honey Bee (Apis mellifera) Workers. J Insect Sci 2022; 22:6. [PMID: 35303101 PMCID: PMC8932410 DOI: 10.1093/jisesa/ieac016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Indexed: 06/14/2023]
Abstract
Laboratory experiments have advanced our understanding of honey bee (Apis mellifera) responses to environmental factors, but removal from the hive environment may also impact physiology. To examine whether the laboratory environment alters the honey bee gut bacterial community and immune responses, we compared bacterial community structure (based on amplicon sequence variant relative abundance), total bacterial abundance, and immune enzyme (phenoloxidase and glucose oxidase) activity of cohort honey bee workers kept under laboratory and hive conditions. Workers housed in the laboratory showed differences in the relative abundance of their core gut taxa, an increase in total gut bacterial abundance, and reduced phenoloxidase activity, compared to bees housed in hives.
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Affiliation(s)
- Casey L Gregory
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA,USA
| | - Richard D Fell
- Department of Entomology, Virginia Tech, Blacksburg, VA,USA
| | - Lisa K Belden
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA,USA
| | - Jenifer B Walke
- Department of Biology, Eastern Washington University, Cheney, WA, USA
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Christen V, Grossar D, Charrière JD, Eyer M, Jeker L. Correlation Between Increased Homing Flight Duration and Altered Gene Expression in the Brain of Honey Bee Foragers After Acute Oral Exposure to Thiacloprid and Thiamethoxam. Front Insect Sci 2021; 1:765570. [PMID: 38468880 PMCID: PMC10926505 DOI: 10.3389/finsc.2021.765570] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 11/19/2021] [Indexed: 03/13/2024]
Abstract
Neonicotinoids as thiamethoxam and thiacloprid are suspected to be implicated in the decline of honey bee populations. As nicotinic acetylcholine receptor agonists, they disturb acetylcholine receptor signaling in insects, leading to neurotoxicity and are therefore globally used as insecticides. Several behavioral studies have shown links between neonicotinoid exposure of bees and adverse effects on foraging activity, homing flight performance and reproduction, but the molecular aspects underlying these effects are not well-understood. In the last years, several studies through us and others showed the effects of exposure to neonicotinoids on gene expression in the brain of honey bees. Transcripts of acetylcholine receptors, hormonal regulation, stress markers, detoxification enzymes, immune system related genes and transcripts of the energy metabolism were altered after neonicotinoid exposure. To elucidate the link between homing flight performance and shifts in gene expression in the brain of honey bees after neonicotinoid exposure, we combined homing flight activity experiments applying RFID technology and gene expression analysis. We analyzed the expression of endocrine factors, stress genes, detoxification enzymes and genes linked to energy metabolism in forager bees after homing flight experiments. Three different experiments (experiment I: pilot study; experiment II: "worst-case" study and experiment III: laboratory study) were performed. In a pilot study, we wanted to investigate if we could see differences in gene expression between controls and exposed bees (experiment I). This first study was followed by a so-called "worst-case" study (experiment II), where we investigated mainly differences in the expression of transcripts linked to energy metabolism between fast and slow returning foragers. We found a correlation between homing flight duration and the expression of cytochrome c oxidase subunit 5A, one transcript linked to oxidative phosphorylation. In the third experiment (experiment III), foragers were exposed in the laboratory to 1 ng/bee thiamethoxam and 8 ng/bee thiacloprid followed by gene expression analysis without a subsequent flight experiment. We could partially confirm the induction of cytochrome c oxidase subunit 5A, which we detected in experiment II. In addition, we analyzed the effect of the feeding mode (group feeding vs. single bee feeding) on data scattering and demonstrated that single bee feeding is superior to group feeding as it significantly reduces variability in gene expression. Based on the data, we thus hypothesize that the disruption of energy metabolism may be one reason for a prolongation of homing flight duration in neonicotinoid treated bees.
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Affiliation(s)
- Verena Christen
- University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Muttenz, Switzerland
| | | | | | - Michael Eyer
- Agroscope, Swiss Bee Research Center, Bern, Switzerland
- Laboratory of Soil Biodiversity, University of Neuchâtel, Neuchâtel, Switzerland
| | - Lukas Jeker
- Agroscope, Swiss Bee Research Center, Bern, Switzerland
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Vidkjær NH, Fomsgaard IS, Kryger P. LC-MS/MS Quantification Reveals Ample Gut Uptake and Metabolization of Dietary Phytochemicals in Honey Bees ( Apis mellifera). J Agric Food Chem 2021; 69:627-637. [PMID: 33416324 PMCID: PMC7884015 DOI: 10.1021/acs.jafc.0c03584] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 11/15/2020] [Accepted: 11/30/2020] [Indexed: 05/13/2023]
Abstract
The honey bee pollen/nectar diet is rich in bioactive phytochemicals and recent studies have demonstrated the potential of phytochemicals to influence honey bee disease resistance. To unravel the role of dietary phytochemicals in honey bee health it is essential to understand phytochemical uptake, bioavailability, and metabolism but presently limited knowledge exists. With this study we aim to build a knowledge foundation. For 5 days, we continuously fed honey bees on eight individual phytochemicals and measured the concentrations in whole and dissected bees by HPLC-MS/MS. Ample phytochemical metabolization was observed, and only 6-30% of the consumed quantities were recovered. Clear differences in metabolization rates were evident, with atropine, aucubin, and triptolide displaying significantly slower metabolism. Phytochemical gut uptake was also demonstrated, and oral bioavailability was 4-31%, with the highest percentages observed for amygdalin, triptolide, and aucubin. We conclude that differences in the chemical properties and structure impact phytochemical uptake and metabolism.
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Affiliation(s)
- Nanna Hjort Vidkjær
- Department
of Biology and Biological Engineering, Chalmers
University of Technology, SE-412 96 Göteborg, Sweden
- Department
of Agroecology, Aarhus University, Forsøgsvej 1, DK-4200 Slagelse, Denmark
| | - Inge S. Fomsgaard
- Department
of Agroecology, Aarhus University, Forsøgsvej 1, DK-4200 Slagelse, Denmark
| | - Per Kryger
- Department
of Agroecology, Aarhus University, Forsøgsvej 1, DK-4200 Slagelse, Denmark
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Chmiel JA, Daisley BA, Pitek AP, Thompson GJ, Reid G. Understanding the Effects of Sublethal Pesticide Exposure on Honey Bees: A Role for Probiotics as Mediators of Environmental Stress. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00022] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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Urbieta-Magro A, Higes M, Meana A, Barrios L, Martín-Hernández R. Age and Method of Inoculation Influence the Infection of Worker Honey Bees ( Apis mellifera) by Nosema ceranae. Insects 2019; 10:E417. [PMID: 31766667 PMCID: PMC6956240 DOI: 10.3390/insects10120417] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/15/2019] [Accepted: 11/18/2019] [Indexed: 01/09/2023]
Abstract
The microsporidian parasite Nosema ceranae is a highly prevalent, global honey bee pathogen. Apis mellifera is considered to be a relatively recent host for this microsporidia, which raises questions as to how it affects its host's physiology, behavior and longevity, both at the individual and colony level. As such, honey bees were inoculated with fresh purified spores of this pathogen, both individually (Group A) or collectively (Group B) and they were studied from 0 to 15 days post-emergence (p.e.) to evaluate the effect of bee age and the method of inoculation at 7 days post-infection. The level of infection was analyzed individually by qPCR by measuring the relative amount of the N. ceranae polar tubule protein 3 (PTP3) gene. The results show that the bee's age and the method of infection directly influence parasite load, and thus, early disease development. Significant differences were found regarding bee age at the time of infection, whereby the youngest bees (new-born and 1 day p.e.) developed the highest parasite load, with this load decreasing dramatically in bees infected at 2 days p.e. before increasing again in bees infected at 3-4 days p.e. The parasite load in bees infected when older than 4 days p.e. diminished as they aged. When the age cohort data was pooled and grouped according to the method of infection, a significantly higher mean concentration and lower variation in N. ceranae infection was evident in Group A, indicating greater variation in experimental infection when spores were administered collectively to bees through their food. In summary, these data indicate that both biological and experimental factors should be taken into consideration when comparing data published in the literature.
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Affiliation(s)
- Almudena Urbieta-Magro
- IRIAF. Instituto Regional de Investigación y Desarrollo Agroalimentario y Forestal, Laboratorio de Patología Apícola, Centro de Investigación Apícola y Agroambiental (CIAPA), Consejería de Agricultura de la Junta de Comunidades de Castilla-La Mancha, Camino de San Martín s/n, 19180 Marchamalo, Spain; (A.U.-M.); (M.H.)
| | - Mariano Higes
- IRIAF. Instituto Regional de Investigación y Desarrollo Agroalimentario y Forestal, Laboratorio de Patología Apícola, Centro de Investigación Apícola y Agroambiental (CIAPA), Consejería de Agricultura de la Junta de Comunidades de Castilla-La Mancha, Camino de San Martín s/n, 19180 Marchamalo, Spain; (A.U.-M.); (M.H.)
| | - Aránzazu Meana
- Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain;
| | - Laura Barrios
- Statistics Department, Computing Center SGAI-CSIC, 28006 Madrid, Spain
| | - Raquel Martín-Hernández
- IRIAF. Instituto Regional de Investigación y Desarrollo Agroalimentario y Forestal, Laboratorio de Patología Apícola, Centro de Investigación Apícola y Agroambiental (CIAPA), Consejería de Agricultura de la Junta de Comunidades de Castilla-La Mancha, Camino de San Martín s/n, 19180 Marchamalo, Spain; (A.U.-M.); (M.H.)
- Instituto de Recursos Humanos para la Ciencia y la Tecnología (INCRECYT-FEDER), Fundación Parque Científico y Tecnológico de Castilla—La Mancha, 02006 Albacete, Spain
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Boff S, Friedel A, Mussury RM, Lenis PR, Raizer J. Changes in social behavior are induced by pesticide ingestion in a Neotropical stingless bee. Ecotoxicol Environ Saf 2018; 164:548-553. [PMID: 30149353 DOI: 10.1016/j.ecoenv.2018.08.061] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 08/13/2018] [Accepted: 08/17/2018] [Indexed: 06/08/2023]
Abstract
Throughout evolutionary history bees have developed complex communication systems. For social bees, communication is important for both the individual and the development of the colony. Successful communication helps bees to recognize relatives, defend the colony, and promote recruitment to optimize foraging of floral resources. Bees' contribution to pollination is of broad environmental and economic importance. However, studies have reported that anthropogenic actions, such as the use of pesticides, negatively affect bee survival and behavior. We tested the effect of a commercially available pesticide mix containing two pesticide classes, a neonicotinoid and a pyrethroid, on the social behavior of the stingless bee, Melipona quadrifasciata (Lepeletier, 1863). After determining a sublethal dose of the pesticides, we tested the effect of an acute dose on antennation and trophallaxis behaviors of worker bees. Our results showed a drastic reduction in the communication and social interactions of bees.
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Affiliation(s)
- Samuel Boff
- Faculty of Biological and Environmental Sciences, Federal University of Grande Dourados, Avenida Dourados-Itahum, km 12, Dourados 79804-970, Mato Grosso do Sul, Brazil; Postgraduate Program in Bioprospecting and General Biology, Federal University of Grande Dourados, Dourados, Mato Grosso do Sul, Brazil; The University of Milan, Department of Food, Environmental and Nutritional Sciences, via Celoria 2, 20133Milan, Italy.
| | - Anna Friedel
- Institute for Biology, Martin-Luther-University Halle-Wittenberg, Hoher Weg 8, 06120 Halle (Saale), Germany
| | - Rosilda Mara Mussury
- Faculty of Biological and Environmental Sciences, Federal University of Grande Dourados, Avenida Dourados-Itahum, km 12, Dourados 79804-970, Mato Grosso do Sul, Brazil; Postgraduate Program in Bioprospecting and General Biology, Federal University of Grande Dourados, Dourados, Mato Grosso do Sul, Brazil; Postgraduate Program in Entomology and Biodiversity Conservation, Federal University of Grande Dourados, Dourados, Mato Grosso do Sul, Brazil
| | - Patricia Roseti Lenis
- Faculty of Biological and Environmental Sciences, Federal University of Grande Dourados, Avenida Dourados-Itahum, km 12, Dourados 79804-970, Mato Grosso do Sul, Brazil; Postgraduate Program in Entomology and Biodiversity Conservation, Federal University of Grande Dourados, Dourados, Mato Grosso do Sul, Brazil
| | - Josué Raizer
- Faculty of Biological and Environmental Sciences, Federal University of Grande Dourados, Avenida Dourados-Itahum, km 12, Dourados 79804-970, Mato Grosso do Sul, Brazil; Postgraduate Program in Entomology and Biodiversity Conservation, Federal University of Grande Dourados, Dourados, Mato Grosso do Sul, Brazil
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Schott M, Bischoff G, Eichner G, Vilcinskas A, Büchler R, Meixner MD, Brandt A. Temporal dynamics of whole body residues of the neonicotinoid insecticide imidacloprid in live or dead honeybees. Sci Rep 2017; 7:6288. [PMID: 28740208 DOI: 10.1038/s41598-017-06259-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 06/09/2017] [Indexed: 01/07/2023] Open
Abstract
In cases of acute intoxication, honeybees often lay in front of their hives for several days, exposed to sunlight and weather, before a beekeeper can take a sample. Beekeepers send samples to analytical laboratories, but sometimes no residues can be detected. Temperature and sun light could influence the decrease of pesticides in bee samples and thereby residues left for analysis. Moreover, samples are usually sent via normal postal services without cooling. We investigated the temporal dynamics of whole-body residues of imidacloprid in live or dead honeybees following a single-meal dietary exposure of 41 ng/bee under various environmental conditions, such as freezing, exposure to UV light or transfer of individuals through the mail system. Immobile, “dead” looking honeybees recovered from paralysis after 48 hours. The decrease of residues in living but paralysed bees was stopped by freezing (= killing). UV light significantly reduced residues, but the mode of transport did not affect residue levels. Group feeding increased the variance of residues, which is relevant for acute oral toxicity tests. In conclusion, elapsed time after poisoning is key for detection of neonicotinoids. Freezing before mailing significantly reduced the decrease of imidacloprid residues and may increase the accuracy of laboratory analysis for pesticides.
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