CCD/Neonicotinoid Data (Studies, Articles, Links) - Page 9
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  1. #161
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    Default Re: Gene expression changes in honey bees induced by sublethal imidacloprid exposure

    Quote Originally Posted by Eduardo Gomes View Post
    Thanks, Eduardo;

    A good example of very weak research designed to support an ideological opinion.

    People susceptible to this kind of persuasion are generally not inclined to dig deep enough to spot the issues that could suggest very different causes for the observations.

    Precise science is not needed to appeal to emotions!
    Frank

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  3. #162

    Default Re: Gene expression changes in honey bees induced by sublethal imidacloprid exposure

    Scientists are scientists.
    Look at the dates.

    I´m very sad that links are still discussed here.
    Well, Barry left and moderation changed.


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    says it all.

  4. #163
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    Default Re: Gene expression changes in honey bees induced by sublethal imidacloprid exposure

    Quote Originally Posted by SiWolKe View Post
    Threads
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    says it all.
    Hello Sibylle - I may be having one of my really 'thick' days today - but what do you mean by "says it all" ? You've flagged-up nearly two thousand active members, so I guess that's part of the point you're making ...

    Maybe I've missed something important within the last few posts ?
    'best
    LJ
    A Heretics Guide to Beekeeping http://heretics-guide.atwebpages.com/

  5. #164
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    Default Re: Gene expression changes in honey bees induced by sublethal imidacloprid exposure


  6. #165

    Default Re: Gene expression changes in honey bees induced by sublethal imidacloprid exposure

    Effects of clothianidin exposure on semen parameters of honey bee drones.
    Abstract : Many problems have been reported on honey bees colonies including fertility problems of queens resulted in production failure. Pesticides can be the cause of this failure in connection with the quality of sperm drone. Thus, the aim of this study was to assess the influence of exposure to syrup contaminated with clothianidin at 0.1 µg/L on semen parameters of drones. Results showed a significant decrease of semen volume and sperm concentration and an increase in sperm mortality rate. As for the energetic state, clothianidin increased cell redox potential, the ATP content of spermatozoa as well as the lactate dehydrogenase activity (LDH). It was concluded that exposure to clothianidin during the sexual maturity of drones could affect the semen quality.
    https://www.cabdirect.org/cabdirect/...ct/20193066560

    Parameterization and sensitivity analysis of a honey bee colony dynamics model for neonicotinoid exposure events using Markov Chain Monte Carlo methods
    Abstract
    Honey bee (Apis mellifera) colony losses have increased in recent decades in both Europe and North America. While multiple stressors to honey bee colonies appear to be driving this decline (including disease, nutrition, genetics), direct exposure to pesticides has been identified as a factor leading to increased bee declines. The simulation model VarroaPop is currently being modified by the USDA and USEPA to predict honey bee hive dynamics in response to pesticide exposure. However, applying this model to pesticides is complicated due to a lack of parameterization information from the supporting literature for many variables, especially those related to in-hive pesticide dynamics. Here, we utilize data from a field study which measured residues of several neonicotinoid insecticides in pollen and tracked population dynamics of exposed hives to improve our estimation of colony simulation model parameters relevant to VarroaPop and the new model components related to pesticides. We use Markov Chain Monte Carlo methods to sample the probability distribution of model parameters and examine the likelihood of each parameter combination, given the field-derived population data. Through this procedure, we obtain posterior distributions which represent the most likely parameter values given a realistic neonicotinoid exposure scenario. We use these pesticide-optimized parameter distributions to run a global sensitivity analysis for the updated posteriors in order to contrast with a sensitivity analysis based on the priors. This helps determine what factors are most important in driving hive success or failure following exposure events.
    https://scholarsarchive.byu.edu/iems...18/Stream-G/7/

    Assessing the Impact of the Conservation Reserve Program on Honey Bee Health
    Key Findings (2014–18)
    • More than one-sixth of all honey bee yards in North Dakota and South Dakota (the top two honey-producing States) meet the key foraging requirements of honey bees just based on the existence of CRP grasslands alone. Thus, the CRP plays a considerable role in supporting the carrying capacity of honey bee colonies in this region (Otto and others, 2018).
    • Honey bee colonies in areas surrounded by grassland, such as those enrolled in the CRP, are 10–15 percent larger than colonies kept in areas surrounded by mostly row crops. A USGS study determined that a bee yard surrounded by mostly grassland can yield an extra $4,100 in annual revenue to a beekeeper compared to a bee yard surrounded by mostly row crop. A beekeeper who manages several hundred bee yards may incur sizable economic gains through nearby CRP and other conservation grass- lands (Smart and others, 2018).
    • The USGS led the first large-scale assessment of native bees on CRP grassland that documented what native bees were present on CRP grasslands and what flowers they used (Otto and others, 2017).
    • The USGS developed a genetic sequencing strategy to rapidly quantify pollen grains collected from bees (Smart and others, 2017). This novel technique allowed the USGS to determine what flowering plants were impor- tant bee food. Knowing what flowers constitute good
    bee food is an important step in improving the cost- effectiveness of the CRP.
    • The USGS launched the “Pollinator Library,” a decision- support tool that can be used by USDA staff for evalu- ating seeding mixes for the CRP (https://www.npwrc. usgs.gov/pollinator/). This website provides users with information on which plants are favored by honey bees and native bees. USGS scientists published a paper demonstrating how USDA staff can use the Pollinator Library to evaluate the cost-effectiveness of CRP seeding mixes (Otto and others, 2017).
    https://pubs.usgs.gov/fs/2018/3082/fs20183082.pdf

    Hazard of a neonicotinoid insecticide on the homing flight of the honeybee depends on climatic conditions and Varroa infestation
    Abstract
    The paradigm for all toxicological bioassays in the risk assessment of pesticide registration reflects the principle that experimental conditions should be controlled to avoid any other factors that may affect the endpoint measures. As honeybee colonies can be frequently exposed to bio-aggressors in real conditions, often concomitantly with pesticides, co-exposure to pesticide/bio-aggressors is becoming a concern for regulatory authorities. We investigated the effects of the neonicotinoid insecticide thiamethoxam on the homingperformances of foragers emerging from colonies differentiated by health status (infestation with Varroa destructor mites, microsporidian parasite Nosema spp. and Deformed Wing Virus). We designed a homing test that has been recently identified to fill a regulatory gap in the field evaluations of sublethal doses of pesticides before their registration. We also assessed the effect of temperature as an environmental factor. Our results showed that the Varroa mite exacerbates homing failure (HF) caused by the insecticide, whereas high temperatures reduce insecticide-induced HF. Through an analytical Effective Dose (ED) approach, predictive modeling results showed that, for instance, ED level of an uninfested colony, can be divided by 3.3 when the colony is infested by 5 Varroa mites per 100 bees and at a temperature of 24 °C. Our results suggest that the health status of honeybee colonies and climatic context should be targeted for a thorough risk assessment.
    https://www.sciencedirect.com/scienc...45653519303534

  7. #166

    Default Re: CCD/Neonicotinoid Data (Studies, Articles, Links)

    Alterations in honey bee gut microorganisms
    Honey bees are associated with gut microorganisms essential for their nutrition and health. The composition of the microbial community can be used as a biological health indicator and is characterized using biomarker fatty acids. Commonly, gut microorganisms are exposed to pathogens and to an array of chemical and biological pest control methods.


    We found a strong negative effect on microbial gut community composition when exposed to the bee pest control chemicals oxytetracycline, oxalic acid and imidacloprid, and when inoculated with the bee pest Nosema spp. and the potential bee pest biocontrol agent Lactobacillus plantarum. Results from the in vitro test with bee pest chemicals showed a differential response of Lactobacillus spp. At the community level, some taxonomic groups were more affected depending on treatment, but sharp changes in the microbial structure were caused by compounds generally considered as bee safe.


    Our results show that pests such as Nosema spp. and pest control methods alter the composition of bee gut microorganisms, which may have severe consequences for pathogen defense, physiology and general honey bee health. In addition, L. plantarum has potential as a biocontrol agent against Nosema spp. © 2018 Society of Chemical Industry
    https://www.ingentaconnect.com/conte...00003/art00035

  8. #167

    Default Re: CCD/Neonicotinoid Data (Studies, Articles, Links)

    Sublethal Effects of the Insecticide Pyrifluquinazon on the European Honey Bee (Hymenoptera: Apidae)
    James M Wilson Troy D Anderson Thomas P Kuhar
    Journal of Economic Entomology, toz014, https://doi.org/10.1093/jee/toz014

    Abstract
    Pyrifluquinazon (PQZ) is an Insecticide Resistance Action Committee (IRAC) Group 9 insecticide that has recently been registered for use in the United States for control of soft-bodied sucking insect pests. Although it has been classified as practically nontoxic to honey bees, Apis mellifera L. (Hymenoptera: Apidae), based on acute contact bioassays, additional information on sublethal effects of this insecticide on honey bees is lacking. Using a combination of laboratory assays with video movement tracking software and near-field evaluations of colonies foraging in a high-tunnel experiment, we determined that, when fed PQZ at a concentration of 84 mg active ingredient (ai)/liter (= ppm) in sugar water, a reduction in overall movement by the foraging worker bees was observed. However, when provided with honey reserves in the hive, honey bees rejected the PQZ-treated sugar water. These results indicate that, if ingested at levels of 84 mg ai/liter, PQZ could have a negative effect on honey bee behavior; however, honey bee workers appear to be able to detect the presence of PQZ in their food and reject it.
    https://academic.oup.com/jee/advance...toz014/5320965

  9. #168

    Default Re: CCD/Neonicotinoid Data (Studies, Articles, Links)

    Honey Bee Exposure to Pesticides: A Four-Year Nationwide Study
    Abstract
    Pollinators, including honey bees, are responsible for the successful reproduction of more than 87% of flowering plant species: they are thus vital to ecosystem health and agricultural services world-wide. To investigate honey bee exposure to pesticides, 168 pollen samples and 142 wax comb samples were collected from colonies within six stationary apiaries in six U.S. states. These samples were analyzed for evidence of pesticides. Samples were taken bi-weekly when each colony was active. Each apiary included thirty colonies, of which five randomly chosen colonies in each apiary were sampled for pollen. The pollen samples were separately pooled by apiary. There were a total of 714 detections in the collected pollen and 1008 detections in collected wax. A total of 91 different compounds were detected: of these, 79 different pesticides and metabolites were observed in the pollen and 56 were observed in the wax. In all years, insecticides were detected more frequently than were fungicides or herbicides: one third of the detected pesticides were found only in pollen. The mean (standard deviation (SD)) number of detections per pooled pollen sample varied by location from 1.1 (1.1) to 8.7 (2.1). Ten different modes of action were found across all four years and nine additional modes of action occurred in only one year. If synergy in toxicological response is a function of simultaneous occurrence of multiple distinct modes of action, then a high frequency of potential synergies was found in pollen and wax-comb samples. Because only pooled pollen samples were obtained from each apiary, and these from only five colonies per apiary per year, more data are needed to adequately evaluate the differences in pesticide exposure risk to honey bees among colonies in the same apiary and by year and location.
    https://www.mdpi.com/2075-4450/10/1/13

  10. #169

    Default Re: CCD/Neonicotinoid Data (Studies, Articles, Links)

    Insects 2019, 10(1), 19; https://doi.org/10.3390/insects10010019
    Initial Exposure of Wax Foundation to Agrochemicals Causes Negligible Effects on the Growth and Winter Survival of Incipient Honey Bee (Apis mellifera) Colonies
    Abstract
    Widespread use of agrochemicals in the U.S. has led to nearly universal contamination of beeswax in honey bee hives. The most commonly found agrochemicals in wax include beekeeper-applied miticides containing tau-fluvalinate, coumaphos, or amitraz, and field-applied pesticides containing chlorothalonil or chlorpyrifos. Wax contaminated with these pesticides negatively affects the reproductive quality of queens and drones. However, the synergistic effects of these pesticides on the growth and survival of incipient colonies remain understudied. We established new colonies using frames with wax foundation that was pesticide free or contaminated with field-relevant concentrations of amitraz alone, a combination of tau-fluvalinate and coumaphos, or a combination of chlorothalonil and chlorpyrifos. Colony growth was assessed by estimating comb and brood production, food storage, and adult bee population during a colony’s first season. We also measured colony overwintering survival. We found no significant differences in colony growth or survivorship between colonies established on pesticide-free vs. pesticide-laden wax foundation. However, colonies that had Varroa destructor levels above 3% in the fall were more likely to die over winter than those with levels below this threshold, indicating that high Varroa infestation in the fall played a more important role than initial pesticide exposure of wax foundation in the winter survival of newly established colonies.
    https://www.mdpi.com/2075-4450/10/1/19

  11. #170

    Default Re: CCD/Neonicotinoid Data (Studies, Articles, Links)

    Combined Toxicity of Insecticides and Fungicides Applied to California Almond Orchards to Honey Bee Larvae and Adults
    Insects 2019, 10(1), 20; https://doi.org/10.3390/insects10010020
    Abstract
    Beekeepers providing pollination services for California almond orchards have reported observing dead or malformed brood during and immediately after almond bloom—effects that they attribute to pesticide exposure. The objective of this study was to test commonly used insecticides and fungicides during almond bloom on honey bee larval development in a laboratory bioassay. In vitro rearing of worker honey bee larvae was performed to test the effect of three insecticides (chlorantraniliprole, diflubenzuron, and methoxyfenozide) and three fungicides (propiconazole, iprodione, and a mixture of boscalid-pyraclostrobin), applied alone or in insecticide-fungicide combinations, on larval development. Young worker larvae were fed diets contaminated with active ingredients at concentration ratios simulating a tank-mix at the maximum label rate. Overall, larvae receiving insecticide and insecticide-fungicide combinations were less likely to survive to adulthood when compared to the control or fungicide-only treatments. The insecticide chlorantraniliprole increased larval mortality when combined with the fungicides propiconazole or iprodione, but not alone; the chlorantraniliprole-propiconazole combination was also found to be highly toxic to adult workers treated topically. Diflubenzuron generally increased larval mortality, but no synergistic effect was observed when combined with fungicides. Neither methoxyfenozide nor any methoxyfenozide-fungicide combination increased mortality. Exposure to insecticides applied during almond bloom has the potential to harm honey bees and this effect may, in certain instances, be more damaging when insecticides are applied in combination with fungicides
    https://www.mdpi.com/2075-4450/10/1/20

  12. #171
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    Default Re: CCD/Neonicotinoid Data (Studies, Articles, Links)

    Quote Originally Posted by BernhardHeuvel View Post
    Alterations in honey bee gut microorganisms
    Honey bees are associated with gut microorganisms essential for their nutrition and health. The composition of the microbial community can be used as a biological health indicator and is characterized using biomarker fatty acids. Commonly, gut microorganisms are exposed to pathogens and to an array of chemical and biological pest control methods.


    We found a strong negative effect on microbial gut community composition when exposed to the bee pest control chemicals oxytetracycline, oxalic acid and imidacloprid, and when inoculated with the bee pest Nosema spp
    https://www.ingentaconnect.com/conte...00003/art00035
    I wonder if that is dribbled or vaporized OA. I read the link but I didn't see which.

    Alex
    Ten years of Beekeeping before varroa. Started again spring of 2014.

  13. #172

    Default Re: CCD/Neonicotinoid Data (Studies, Articles, Links)

    Dribbled. Don't think sublimated oxalic acid do the same harm, since the bees don't lick it. It is known, that damage to the midgut by oxalic acid increases as the sugar content increases in the dribble solution. No sugar, no lick.

  14. #173
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    Default Re: CCD/Neonicotinoid Data (Studies, Articles, Links)

    Quote Originally Posted by BernhardHeuvel View Post
    Dribbled. Don't think sublimated oxalic acid do the same harm, since the bees don't lick it. It is known, that damage to the midgut by oxalic acid increases as the sugar content increases in the dribble solution. No sugar, no lick.
    Thanks for the response. That is what I was thinking/hoping.

    Alex
    Ten years of Beekeeping before varroa. Started again spring of 2014.

  15. #174

    Default Re: CCD/Neonicotinoid Data (Studies, Articles, Links)

    The novel pesticide flupyradifurone (Sivanto) affects honeybee motor abilities

    Abstract
    Honeybees and other pollinators are threatened by changing landscapes and pesticides resulting from intensified agriculture. In 2018 the European Union prohibited the outdoor use of three neonicotinoid insecticides due to concerns about pollinators. A new pesticide by the name of “Sivanto” was recently released by Bayer AG. Its active ingredient flupyradifurone binds to the nicotinic acetylcholine receptor (AchR) in the honeybee brain, similar to neonicotinoids. Nevertheless, flupyradifurone is assumed to be harmless for honeybees and can even be applied on flowering crops. So far, only little has been known about sublethal effects of flupyradifurone on honeybees. Intact motor functions are decisive for numerous behaviors including foraging and dancing. We therefore selected a motor assay to investigate in how far sublethal doses of this pesticide affect behavior in young summer and long-lived winter honeybees. Our results demonstrate that flupyradifurone (830 µmol/l) can evoke motor disabilities and disturb normal motor behavior after a single oral administration (1.2 µg/bee). These effects are stronger in long-lived winter bees than in young summer bees. After offering an equal amount of pesticide (1.0–1.75 µg) continuously over 24 h with food the observed effects are slighter. For comparisons we repeated our experiments with the neonicotinoid imidacloprid. Intriguingly, the alterations in behavior induced by this pesticide (4 ng/bee) were different and longer-lasting compared to flupyradifurone, even though both substances bind to nicotinic acetylcholine receptors.
    https://link.springer.com/article/10...46-019-02028-y
    https://doi.org/10.1007/s10646-019-02028-y

  16. #175

    Default Re: CCD/Neonicotinoid Data (Studies, Articles, Links)

    DETECTION OF THE PESTICIDE IMIDACLOPRID IN HONEY

    K. E. Burkin

    Abstract: Studies have been carried out to determine the imidacloprid pesticide content of the neonicotinoid group in honey, including sample preparation and subsequent analysis by high-performance liquid chromatography on a chromatograph with a UV-detector. The optimum conditions providing the maximum extraction of imidacloprid from honey are selected.

    http://tipkadpo.ru/data/uploads/nauk...__.pdf#page=83

  17. #176

    Default Re: CCD/Neonicotinoid Data (Studies, Articles, Links)

    Impact of acute oral exposure to thiamethoxam on the homing, flight, learning acquisition and short‐term retention of Apis cerana

    Changsheng Ma Yongkui Zhang Jia Sun Muhammad Imran Huipeng Yang Jie Wu … other authors /et al.
    First published: 18 March 2019
    https://doi.org/10.1002/ps.5411
    https://onlinelibrary.wiley.com/doi/abs/10.1002/ps.5411

    Abstract
    BACKGROUND

    Thiamethoxam (TMX) represents the second‐generation of neonicotinoids that has been widely applied in agricultural activities, while how TMX alters the behavior of Apis cerana, an important native honey bee species in China, is not clear. We carried out three independent experiments to study the impact of acute oral treatment of 20 μl TMX at concentrations of 2.4 ppb (0.048 ng/bee) and 10 ppb (0.2 ng/bee) on the homing, flight, learning acquisition and short‐term retention ability of A. cerana. The homing ability was assessed by the catch‐and‐release method, the flight ability was assessed by flight mills, and the learning acquisition and short‐term retention were evaluated by the proboscis extension response method.

    RESULTS

    When treated with 10 ppb of TMX, bees had a significantly higher average homing time, mean flight velocity, flying distance, and flying duration than the control, whereas 2.4 ppb concentration did not cause any significant effect on homing or flight ability. Bees treated with either 2.4 ppb or 10 ppb TMX had significantly lower learning acquisition and short‐term retention ability.

    CONCLUSION

    Results suggest that acute oral exposure to 10 ppb of TMX altered the short distance homing time, flight ability, and learning acquisition and short‐term retention ability. Our study also highlights the concern that acute oral exposure to a low concentration of 2.4 ppb could have consequences on the behavior of A. creana. Those multiple sublethal alterations on A. cerana's behavior indicate that TMX are likely causing complex, but negative consequences on bee health in the field.

  18. #177

    Default Re: CCD/Neonicotinoid Data (Studies, Articles, Links)

    Effects of sublethal doses of clothianidin and/or V. destructor on honey bee (Apis mellifera) self-grooming behavior and associated gene expression

    Nuria Morfin, Paul H. Goodwin, Greg. J. Hunt & Ernesto Guzman-Novoa

    Scientific Reportsvolume 9, Article number: 5196 (2019)


    Abstract

    Little is known about the combined effects of stressors on social immunity of honey bees (Apis mellifera) and related gene expression. The interaction between sublethal doses of a neurotoxin, clothianidin, and the ectoparasite, Varroa destructor, was examined by measuring differentially expressed genes (DEGs) in brains, deformed wing virus (DWV) and the proportion and intensity of self-grooming. Evidence for an interaction was observed between the stressors in a reduction in the proportion of intense groomers. Only the lowest dose of clothianidin alone reduced the proportion of self-groomers and increased DWV levels. V. destructor shared a higher proportion of DEGs with the combined stressors compared to clothianidin, indicating that the effects of V. destructor were more pervasive than those of clothianidin when they were combined. The number of up-regulated DEGs were reduced with the combined stressors compared to clothianidin alone, suggesting an interference with the impacts of clothianidin. Clothianidin and V. destructor affected DEGs from different biological pathways but shared impacts on pathways related to neurodegenerative disorders, like Alzheimer’s, which could be related to neurological dysfunction and may explain their negative impacts on grooming. This study shows that the combination of clothianidin and V. destructor resulted in a complex and non-additive interaction.

    ...


    Discussion

    This study examined the effect of two stressors, sublethal doses of clothianidin and V. destructor on gene expression in the brain and increases in a mite-transmitted virus, DWV, to better understand how these two stressors act separately and together to affect honey bees on aspects of neural activity related to self-grooming behavior. Among the two stressors, clothianidin alone had a greater effect than V. destructor alone to reduce self-grooming behavior, based on the proportion of bees that self-groomed and the proportion of bees that self-groomed intensively, as well as the number of up-regulated DEGs. However, the results with the combination of V. destructor with clothianidin showed that combining each stressor did not result in a simple additive effect in the number of DEGs or the KEGG pathways associated with them.

    One unexpected result of this study was that both DWV levels and the proportion of bees that self-groomed were affected only by the lowest dose of clothianidin without V. destructor. This may indicate that effects of DWV and grooming could be linked in some manner. Unexpectedly, higher doses of clothianidin in absence of mites, or the same dose of clothianidin combined with V. destructor, did not have the same impacts, indicating that there was a relatively specific impact from the lowest dose of clothianidin tested. Hormesis occurs when there is a beneficial biological response to a low exposure to a stressor28. In this case, a beneficial response did not occur at the lowest dose, but the effect could be similar to hormesis. At the lowest clothianidin dose, it would still bind to nicotinic acetylcholine receptors of the neural cells resulting in neural stimulation but may not overstimulate it to the level of toxic doses that block receptors impeding the action of the neurotransmitter ACh29. At very low doses, clothianidin stimulation of the central nervous system may just be sufficient to somehow interfere with self-grooming and resistance to a virus. While these results imply hormesis, future research should investigate more sublethal doses of clothianidin to confirm this by determining the range of doses that results in these effects.

    ...

  19. #178

    Default Re: CCD/Neonicotinoid Data (Studies, Articles, Links)

    Effects of three common pesticides on survival, food consumption and midgut bacterial communities of adult workers Apis cerana and Apis mellifera

    YangYangaShilongMaabZhenxiongYancFengLiudQingyunDi aoaPingliDaia

    https://doi.org/10.1016/j.envpol.2019.03.077

    Highlights

    Apis mellifera was more sensitive to chlorpyrifos and dimethoate than Apis cerana.


    Amitraz at a concentration of 7.8 mg/L impacted Apis cerana survival.


    Chlorpyrifos at a concentration of 3.0 mg/L impacted Apis cerana survival.


    Dimethoate at a concentration of 1.0 mg/L impacted both Apis mellifera and Apis cerana survival.


    There was a significant difference in microbiota species richness among treatments at day 15.


    Abstract
    The acute and chronic toxicity of 3 common pesticides, namely, amitraz, chlorpyrifos and dimethoate, were tested in Apis mellifera and Apis cerana. Acute oral toxicity LC50 values were calculated after 24 h of exposure to contaminated syrup, and chronic toxicity was tested after 15 days of exposure to 2 sublethal concentrations of pesticides. The toxicity of the tested pesticides to A. mellifera and A. cerana decreased in the order of dimethoate > chlorpyrifos > amitraz. A. mellifera was slightly more sensitive to chlorpyrifos and dimethoate than A. cerana, while A. cerana was more sensitive to amitraz than A. mellifera. Chronic toxicity tests showed that 1.0 mg/L dimethoate reduced the survival of the two bee species and the food consumption of A. mellifera, while 1.0 mg/L amitraz and 1.0 mg/L chlorpyrifos did not affect the survival or food consumption of the two bee species. The treatment of syrup with amitraz at a concentration equal to 1/10th of the LC50 value did not affect the survival of or diet consumption by A. mellifera and A. cerana; however, chlorpyrifos and dimethoate at concentrations equal to 1/10th of their respective LC50 values affected the survival of A. cerana. Furthermore, intestinal bacterial communities were identified using high-throughput sequencing targeting the V3V4 regions of the 16S rDNA gene. All major honey bee intestinal bacterial phyla, including Proteobacteria (62.84%), Firmicutes (34.04%), and Bacteroidetes (2.02%), were detected. There was a significant difference in the microbiota species richness of the two species after 15 days; however, after 30 days, no significant differences were found in the species diversity and richness between A. cerana and A. mellifera exposed to 1.0 mg/L amitraz and 1.0 mg/L chlorpyrifos. Overall, our results confirm that acute toxicity values are valuable for evaluating the chronic toxicity of these pesticides to honey bees.

  20. #179

    Default Sub-lethal concentrations of neonicotinoid insecticides at the field level affect neg

    Sub-lethal concentrations of neonicotinoid insecticides at the field level affect negatively honey yield: Evidence from a 6-year survey of Greek apiaries

    Robert G. Chambers, Konstantinos Chatzimichael, Vangelis Tzouvelekas

    Abstract
    The threats posed by neonicotinoid insecticides to bee populations have been the focus of considerable research. Previous work has shed new light on the effects of neonicotinoids on bees by uncovering pathways through which neonicotinoids affect bee population dynamics and the potential interactions they have with exogenous stressors. Yet, little is known about whether these effects translate in a field-relevant setting to substantial losses in honey yields for commercial beekeepers. Here, we used data from a 6-year survey of 60 apiaries in Greece and economic modelling to assess at the field level the effects of neonicotinoid insecticides on honey production. Based on production function estimates, we found that sub-lethal concentrations of two widely used neonicotinoid insecticides (imidacloprid and thiamethoxam) detected in the nectar of flowers resulted in substantial losses in honey production for commercial beekeepers in our sample. By simulating a scenario with ideal pathogenic and environmental conditions, we found that the magnitude of the neonicotinoid effects decreases significantly under ideal conditions providing evidence for possible synergies at the field between neonicotinoids and environmental and pathogenic factors. Moreover, in a replicated study with grouped apiaries, we found evidence that the marginal effects of neonicotinoids on honey production may vary across apiaries facing different conditions.

    https://economics.soc.uoc.gr/wpa/docs/1901.pdf

  21. #180
    Join Date
    Feb 2018
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    Lambton Shores, Ontario, Canada
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    Default Re: CCD/Neonicotinoid Data (Studies, Articles, Links)

    Quote Originally Posted by BernhardHeuvel View Post
    Effects of three common pesticides on survival, food consumption and midgut bacterial communities of adult workers Apis cerana and Apis mellifera

    YangYangaShilongMaabZhenxiongYancFengLiudQingyunDi aoaPingliDaia

    https://doi.org/10.1016/j.envpol.2019.03.077

    Highlights

    Apis mellifera was more sensitive to chlorpyrifos and dimethoate than Apis cerana.


    Amitraz at a concentration of 7.8 mg/L impacted Apis cerana survival.


    Chlorpyrifos at a concentration of 3.0 mg/L impacted Apis cerana survival.


    Dimethoate at a concentration of 1.0 mg/L impacted both Apis mellifera and Apis cerana survival.


    There was a significant difference in microbiota species richness among treatments at day 15.
    There's a hugely flawed study if I ever saw one! The concentrations of all of those is around the tank concentration used in the field. So even if the bees drank right from the sprayer on the tractor, they'd probably "bee" OK. For example 3.0 mg/L of chlorpyrifos = 0.3%; when you prepare chlorpyrifos for spraying you dilute it to 0.1% to 0.5% in the tank

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