Beesource Beekeeping Forums banner

181 - 200 of 212 Posts

1,750 Posts
Cauia, Eliza & Siceanu, & Vișan, & Colța, & Spulber,. (2020). Monitoring the Field-Realistic Exposure of Honeybee Colonies to Neonicotinoids by An Integrative Approach: A Case Study in Romania. Diversity. 12. 24. 10.3390/d12010024.

Honeybees (Apis mellifera L.) are excellent biosensors that can be managed to collect valuable information about environmental contamination. The main objective of the present study was to design and apply an integrative protocol to monitor honeybee colony activity and sample collection by using electronic technologies combined with classical methods in order to evaluate the exposure of honeybees to the neonicotinoids that are used in melliferous intensive crops. The monitored honeybee colonies were especially prepared and equipped to maximize their chances to collect representative samples in order to express, as well as possible, the pesticide residues that existed in the targeted crops. The samples of honey, pollen and honeybees were collected, preserved and prepared to fulfill the required quality and quantity criteria of the accredited laboratories. In total, a set of fifty samples was collected from fields, located in different areas of intensive agriculture in Romania, and was analyzed for five neonicotinoids. The obtained results show that 48% of the total analyzed samples (n = 50) contained one or more detected or quantified neonicotinoid residues. The main conclusion is that the proposed approach for sample collection and preparation could improve the evaluation methodologies for analyzing honeybees’ exposure to pesticides.

Comment: we found, that freezing bees greatly improved in finding the residues in the lab. Also collect poisoned bees that are still alive. The process of rotting in the bee greatly destroys residues.

1,750 Posts
Honeybees fail to discriminate floral scents in a complex learning task after consuming a neonicotinoid pesticide


Neonicotinoids are pesticides used to protect crops but with known secondary influences at sublethal doses on bees. Honeybees use their sense of smell to identify the queen and nestmates, to signal danger and to distinguish flowers during foraging. Few behavioural studies to date have examined how neonicotinoid pesticides affect the ability of bees to distinguish odours. Here, we use a differential learning task to test how neonicotinoid exposure affects learning, memory, and olfactory perception in foraging-age honeybees. Bees fed with thiamethoxam could not perform differential learning and could not distinguish odours during short and long-term memory tests. Our data indicate that thiamethoxam directly impacts the cognitive processes involved in working memory required during differential olfactory learning. Using a combination of behavioural assays, we also identified that thiamethoxam has a direct impact on the olfactory perception of similar odours. Honeybees fed with other neonicotinoids (clothianidin, imidacloprid, dinotefuran) performed the differential learning task, but at a slower rate than the control. These bees could also distinguish the odours. Our data are the first to show that neonicotinoids have compound specific effects on the ability of bees to perform a complex olfactory learning task. Deficits in decision-making caused by thiamethoxam exposure could be more harmful than other neonicotinoids, leading to inefficient foraging and a reduced ability to identify nest mates.

Honeybees fail to discriminate floral scents in a complex learning task after consuming a neonicotinoid pesticide
Julie A. Mustard, Anne Gott, Jennifer Scott, Nancy L. Chavarria, Geraldine A. Wright
Journal of Experimental Biology 2020 : jeb.217174 doi: 10.1242/jeb.217174 Published 6 February 2020

1,750 Posts
Widespread contamination of wildflower and bee-collected pollen with complex mixtures of neonicotinoids and fungicides commonly applied to crops

Environment International
Volume 88, March 2016, Pages 169-178

• Pollen of oilseed rape and wildflowers growing nearby contained a wide range of pesticides.
• Pollen collected by honeybees and bumblebees also contained a broad range of pesticides.
• Pesticide exposure of bumblebee colonies in urban areas was lower than in rural areas.

There is considerable and ongoing debate as to the harm inflicted on bees by exposure to agricultural pesticides. In part, the lack of consensus reflects a shortage of information on field-realistic levels of exposure. Here, we quantify concentrations of neonicotinoidinsecticides and fungicides in the pollen of oilseed rape, and in pollen of wildflowers growing near arable fields. We then compare this to concentrations of these pesticides found in pollen collected by honey bees and in pollen and adult bees sampled from bumble bee colonies placed on arable farms. We also compared this with levels found in bumble bee colonies placed in urban areas. Pollen of oilseed rape was heavily contaminated with a broad range of pesticides, as was the pollen of wildflowers growing nearby. Consequently, pollen collected by both bee species also contained a wide range of pesticides, notably including the fungicides carbendazim, boscalid, flusilazole, metconazole, tebuconazole and trifloxystrobin and the neonicotinoids thiamethoxam, thiacloprid and imidacloprid. In bumble bees, the fungicides carbendazim, boscalid, tebuconazole, flusilazole and metconazole were present at concentrations up to 73 nanogram/gram (ng/g). It is notable that pollen collected by bumble bees in rural areas contained high levels of the neonicotinoids thiamethoxam (mean 18 ng/g) and thiacloprid (mean 2.9 ng/g), along with a range of fungicides, some of which are known to act synergistically with neonicotinoids. Pesticide exposure of bumble bee colonies in urban areas was much lower than in rural areas. Understanding the effects of simultaneous exposure of bees to complex mixtures of pesticides remains a major challenge.

1,750 Posts
A bit older, but we missed it here.

Intersections between neonicotinoid seed treatments and honey bees

Christian H, Krupke Elizabeth, Y.Long
Current Opinion in Insect Science
Volume 10, August 2015, Pages 8-13

Synthesis and future directions
The additive effects of these various exposure routes are still being quantified. However, given the area devoted to production of crops grown from neonicotinoid-treated seeds, it is clear that a great degree of temporal and spatial overlap exists between neonicotinoids and pollinators and other non-target organisms. Exposure can take place through various matrices*—*including air-borne and stationary dusts, soil, plant products, and water. For honey bees, where most current research is focused, future estimates of individual and colony-level effects of these exposures should incorporate these multiple routes into assessments of risk posed by neonicotinoid residues. Of particular interest is the typical period of sowing of many annual crops grown from neonicotinoid-treated seeds, which corresponds closely with flowering of spring blossoms and the concomitant increase in honey bee foraging activity across the landscape [45].

1,750 Posts
Thiamethoxam impairs honey bee visual learning, alters decision times, and T increases abnormal behaviors

Learning is important for honey bee fitness and the pollination services that they provide. Neonicotinoid pesticides impair learning, fitness, colony health, and pollination, but most studies on how they affect bee learning have focused on olfactory learning. We tested the effects of field realistic doses of 0.8 ng/bee and 1.34 ng/bee of the neonicotinoid pesticide, thiamethoxam (TMX), on bee visual learning. We adapted a T-maze bioassay and classically conditioned bees to associate sugar reward with a simulated flower color (blue or yellow light) in a choice assay. At 1.34 ng/bee, TMX significantly reduced correct choices in the final learning trial as compared to the control treatment. There was no TMX effect in our 1-h memory test. We found stronger effects on decision time and abnormal behaviors. TMX decreased bee decision times, a potential byproduct of induced hyperactivity since bees walked to make choices. Behaviors (falling, trembling, and rapid abnormal movements) were sig- nificantly increased by both TMX doses as compared to the control treatment. These results suggest that the effects of neonicotinoids on bee visual learning should be further studied and incorporated into Risk Assessment protocols.

Ecotoxicology and Environmental Safety
Volume 193, 15 April 2020, 110367
Joshua C. Ludicke, James C.Nieh

1,750 Posts
The miticide thymol in combination with trace levels of the neonicotinoid imidacloprid reduces visual learning performance in honey bees (Apis mellifera)

Despite growing concerns over the impacts of agricultural pesticides on honey bee health, miticides (a group of pesticides used within hives to kill bee parasites) have received little attention. We know very little about how miticides might affect bee cognition, particularly in interaction with other known stressors, such as crop insecticides. Visual learning is essential for foraging bees to find their way to flowers, recognize them, and fly back to the nest. Using a standardized aversive visual conditioning assay, we tested how field exposure to three pesticides affects visual learning in European honey bees (Apis mellifera). Our pesticides were two common miticides, thymol in the commercial formulation Apiguard® and tau-fluvalinate in the formulation Apistan® and one neonicotinoid, imidacloprid. We found no effect of miticides alone, nor of field-relevant doses of imidacloprid alone, but bees exposed to both thymol and imidacloprid showed reduced performance in the visual learning assay.

Colin, T., Plath, J.A., Klein, S. et al. The miticide thymol in combination with trace levels of the neonicotinoid imidacloprid reduces visual learning performance in honey bees (Apis mellifera). Apidologie (2020).

1,750 Posts
Effects of thiamethoxam and spinosad on the survival and hypopharyngeal glands of the African honey bee (Apis mellifera intermissa)

Insecticides can affect development and survival of non-target and beneficial arthropods like honey bees (Apis mellifera L.). Thiamethoxam and spinosad are widely used as pesticides in agriculture but they have become an important concern for beekeepers and researchers focusing on bee health; multiple reports stressed adverse effects on bees, notably on honey bees. The present study aims to evaluate the impact of these two insecticides on the development of the HPGs and on the survival of Apis mellifera intermissa a native African subspecies of honey bee present in Algeria. Newly emerged workers were acutely and chronically exposed to thiamethoxam and spinosad through sugar syrup and pollen pastry. The effects of these insecticides were assessed by measuring the size of HPGs acini and the total head protein content. The survival of the workers was also evaluated over 60 days when they were chronically exposed to the insecticides at concentrations corresponding to LC25 and LC10. We found that the insecticide-treated workers, after both acute and chronic exposure, exhibited smaller and irregularly shaped HPG acini. The total head protein content also decreased in treated individuals with the two concentrations of insecticides at day 6 and 9 compared to the respective controls. While the control group exhibited an LT50 (i.e. the time needed to kill 50% of the tested workers) of 22 days, the LT50 was only 3 days for the workers exposed to the LC25 of spinosad and all workers were dead at day 17. In contrast, thiamethoxam exposure at LC25 had no significant detrimental effect on honey bee survival. This study demonstrated the toxicity of thiamethoxam and spinosad to workers of A. mellifera intermissa and highlighted potential detrimental effects of the bioinsecticide spinosad on HPGs and survival of the bee workers.

Menail, Ahmed H.; Boutefnouchet-Bouchema, Wided F.; Haddad, Nizar; Taning, Clauvis N.T.; Smagghe, Guy; Loucif-Ayad, Wahida
Effects of thiamethoxam and spinosad on the survival and hypopharyngeal glands of the African honey bee (Apis mellifera intermissa)
Entomologia Generalis (2020)
DOI: 10.1127/entomologia/2020/0796

1,750 Posts
Characterizing honey bee exposure and effects from pesticides for chemical prioritization and life cycle assessment

• Model for quantifying pesticide field exposure and ecotoxicity effects of bees.

• Integration of bee impacts in risk screening and life cycle impact assessment.

• Defined bee intake and dermal contact fractions as novel metrics for exposure.

• Case study on two pesticides on oilseed rape affecting 1260–1,360,000 bees/kg applied.

• Nectar foragers are the most affected forager type, with 32–190 ppm pesticide intake.

Agricultural pesticides are key contributors to pollinator decline worldwide. However, methods for quantifying impacts associated with pollinator exposure to pesticides are currently missing in comparative risk screening, chemical substitution and prioritization, and life cycle impact assessment methods. To address this gap, we developed a method for quantifying pesticide field exposure and ecotoxicity effects of honey bees as most economically important pollinator species worldwide. We defined bee intake and dermal contact fractions representing respectively oral and dermal exposure per unit mass applied, and tested our model on two pesticides applied to oilseed rape. Our results show that exposure varies between types of forager bees, with highest dermal contact fraction of 59 ppm in nectar foragers for lambda-cyhalothrin (insecticide), and highest oral intake fractions of 32 and 190 ppm in nectar foragers for boscalid (fungicide) and lambda-cyhalothrin, respectively. Hive oral exposure is up to 115 times higher than forager oral exposure. Combining exposure with effect estimates yields impacts, which are three orders of magnitude higher for the insecticide. Overall, nectar foragers are the most affected forager type for both pesticides, dominated by oral exposure. Our framework constitutes an important step toward integrating pollinator impacts in chemical substitution and life cycle impact assessment, and should be expanded to cover all relevant pesticide-crop combinations.

Environment International
Volume 138, May 2020, 105642
Characterizing honey bee exposure and effects from pesticides for chemical prioritization and life cycle assessment
Eleonora Crenna, Olivier Jolliet, Elena Collina, Serenella Sala, Peter Fantke

1,750 Posts
A Review of Sub-lethal Neonicotinoid Insecticides Exposure and Effects on Pollinators

Purpose of Review
Beekeepers around the world have been reporting the ongoing weakening of honeybee health and subsequently the increasing colony losses since 1990. However, it was not until the abrupt emergence of colony collapse disorder (CCD) in the 2000s that has raised the concern of losing this important perennial pollinator. In this report, we provide a summary of the sub-lethal effects of pesticides, in particular of neonicotinoids, on pollinators’ health from papers published in peer-review journals.

Recent Findings
We have identified peer-review papers that are relevant to examine the effects of sub-lethal pesticide exposures on the health of honeybees (Apis mellifera), bumblebees (Bombus terrestris), and other bees from a literature search on PubMed and Google Scholar using the following combined keywords of “pollinators,” “honeybee,” “bees,” “pesticides,” or “neonicotinoids,” and from a cross-reference check of a report made available by the European Parliament in preparation to fulfill their regulatory mandate on the issue of protecting pollinators among their membership nations.

The weight-of-evidence of this review clearly demonstrated bees’ susceptibility to insecticides, in particular to neonicotinoids, and the synergistic effects to diseases that are commonly present in bee colonies. One important aspect of assessing and managing the risks posed by neonicotinoids to bees is the chronic effects induced by exposures at the sub-lethal levels. More than 90% of literature published after 2009 directly or indirectly demonstrated the adverse health effects associated with sub-lethal exposure to neonicotinoids, including abnormal foraging activities, impaired brood development, neurological or cognitive effects, and colony collapse disorder.

Lu, C., Hung, Y. & Cheng, Q. A Review of Sub-lethal Neonicotinoid Insecticides Exposure and Effects on Pollinators. Curr Pollution Rep (2020).

References for further review/research:

Abbott VA, Nadeau JL, Higo HA, Winston ML. Lethal and sublethal effects of imidacloprid on Osmia lignaria and clothianidin on Megachile rotundata (Hymenoptera: Megachilidae). J Econ Entomol. 2008;101(3):784–96.

Alaux C, Brunet JL, Dussaubat C, Mondet F, Tchamitchan S, Cousin M, et al. Interactions between Nosema microspores and a neonicotinoid weaken honeybees (Apis mellifera). Environ Microbiol. 2010;12(3):774–82.

Australian Government. Overview report neonicotinoids and the health of honey bees in Australia 2014. Accessed 12 May 2018.

Bernal J, Garrido-Bailón E, Del Nozal MJ, González-Porto AV, Martín-Hernández R, Diego JC, et al. Overview of pesticide residues in stored pollen and their potential effect on bee colony (Apis mellifera) losses in Spain. J Econ Entomol. 2010;103(6):1964–71.

Biddinger DJ, Robertson JL, Mullin C, Frazier J, Ashcraft SA, Rajotte EG, et al. Comparative toxicities and synergism of apple orchard pesticides to Apis mellifera (L.) and Osmia cornifrons (Radoszkowski). PLoS One. 2013;8(9):e72587.

Blanchard P, Schurr F, Celle O, Cougoule N, Drajnudel P, Thiéry R, et al. First detection of Israeli acute paralysis virus (IAPV) in France, a dicistrovirus affecting honeybees (Apis mellifera). J Invertebr Pathol. 2008;99:348–50.

Boily M, Sarrasin B, Deblois C, Aras P, Chagnon M. Acetylcholinesterase in honey bees (Apis mellifera) exposed to neonicotinoids, atrazine and glyphosate: laboratory and field experiments. Environ Sci Pollut Res Int. 2013;20(8):5603–14.

Bryden J, Gill RJ, Mitton RA, Raine NE, Jansen VA. Chronic sublethal stress causes bee colony failure. Ecol Lett. 2013;16:1463–9.

Catae AF, Roat TC, De Oliveira RA, Ferreira Nocelli RC, Malaspina O. Cytotoxic effects of thiamethoxam in the midgut and Malpighian tubules of Africanized Apis mellifera (Hymenoptera: Apidae). Microsc Res Tech. 2014;77:274–81.

Cepero A, Ravoet J, Gómez-Moracho T, Bernal JL, Del Nozal MJ, Bartolomé C, et al. Holistic screening of collapsing honey bee colonies in Spain: a e study. BMC Res Notes. 2014;7(1):649.

Chauzat MP, Faucon JP, Martel AC, Lachaize J, Cougoule N, Aubert M. A survey of pesticide residues in pollen loads collected by honey bees in France. J Econ Entomol. 2006;99(2):253–62.

Christopher Cutler G, Scott-Dupree CD. A field study examining the effects of exposure to neonicotinoid seed-treated corn on commercial bumble bee colonies. Ecotoxicology. 2014;23(9):1755–63.

Cox-Foster DL, Conlan S, Holmes EC, Palacios G, Evans JD, Moran NA, et al. Metagenomic survey of microbes in honey bee colony collapse disorder. Science. 2007;318:283–7.

Cresswell JE, Page CJ, Uygun MB, Holmbergh M, Li Y, Wheeler JG, et al. Differential sensitivity of honey bees and bumble bees to a dietary insecticide (imidacloprid). Zoology (Jena). 2012;115(6):365–71.

Cresswell JE, Robert FX, Florance H, Smirnoff N. Clearance of ingested neonicotinoid pesticide (imidacloprid) in honey bees (Apis mellifera) and bumblebees (Bombus terrestris). Pest Manag Sci. 2014;70(2):332–7.

Cutler CG, Scott-Dupree CD, Drexler DM. Honey bees, neonicotinoids and bee incident reports: the Canadian situation. Pest Manag Sci. 2014;70(5):779–83.

de Almeida RC, Roat TC, Tavares DA, Cintra-Socolowski P, Malaspina O. Brain morphophysiology of Africanized bee Apis mellifera exposed to sublethal doses of imidacloprid. Arch Environ Contam Toxicol. 2013;65(2):234–43.

de Miranda JR, Cordoni G, Budge G. The acute bee paralysis virus-Kashmir bee virus-Israeli acute paralysis virus complex. J Invertebr Pathol. 2010;103:S30–47.

Decourtye A, Devillers J, Cluzeau S, Charreton M, Pham-Delègue MH. Effects of imidacloprid and deltamethrin on associative learning in honeybees under semi-field and laboratory conditions. Ecotoxicol Environ Saf. 2004a;57:410–9.

Decourtye A, Armengaud C, Renou M, Devillers J, Cluzeau S, Gauthier M, et al. Imidacloprid impairs memory and brain metabolism in the honeybee (Apis mellifera L.). Pestic Biochem Physiol. 2004b;78:83–92.
Derecka K, Blythe MJ, Malla S, Genereux DP, Guffanti A, Pavan P, et al. Transient exposure to low levels of insecticide affects metabolic networks of honeybee larvae. PLoS One. 2013;8(7):e68191.

Di Prisco G, Pennacchio F, Caprio E, Boncristiani HF Jr, Evans JD, Chen Y. Varroa destructor is an effective vector of Israeli acute paralysis virus in the honeybee, Apis mellifera. J Genet Virol. 2011;92(Pt 1):151–5.

Di Prisco G, Cavaliere V, Annoscia D, Varricchio P, Caprio E, Nazzi F, et al. Neonicotinoid clothianidin adversely affects insect immunity and promotes replication of a viral pathogen in honey bees. Proc Natl Acad Sci U S A. 2013;110(46):18466–71.

Doublet V, Labarussias M, de Miranda JR, Moritz RFA, Paxton RJ. Bees under stress: sublethal doses of a neonicotinoid pesticide and pathogens interact to elevate honey bee mortality across the life cycle. Environ Microbiol. 2014.

Eiri DM, Nieh JC. A nicotinic acetylcholine receptor agonist affects honey bee sucrose responsiveness and decreases waggle dancing. J Exp Biol. 2012;215(Pt 12):2022–9.

El Hassani AK, Dacher M, Gauthier M, Armengaud C. Effects of sublethal doses of fipronil on the behavior of the honeybee (Apis mellifera). Pharmacol Biochem Behav. 2005;82:30–9.

El Hassani AK, Dacher M, Gary V, Lambin M, Gauthier M, Armengaud C. Effects of sublethal doses of acetamiprid and thiamethoxam on the behavior of the honeybee (Apis mellifera). Arch Environ Contam Toxicol. 2008;54:653–61.

Erickson B. Europe bans three neonicotinoids. Chem Eng News. 2013;91(18):11.

Farooqui T. A potential link among biogenic amines-based pesticides, learning and memory, and colony collapse disorder: a unique hypothesis. Neurochem Int. 2013;62(1):122–36.

Feltham H, Park K, Goulson D. Field realistic doses of pesticide imidacloprid reduce bumblebee pollen foraging efficiency. Ecotoxicology. 2014;23:317–23.

Fischer J, Müller T, Spatz AK, Greggers U, Grünewald B, Menze R. Neonicotinoids interfere with specific components of navigation in honeybees. PLoS One. 2014;9(3):e91364.

Gels JA, Held DW, Potter DA. Hazards of insecticides to the bumble bees Bombus impatiens (Hymenoptera: Apidae) foraging on flowering white clover in turf. J Econ Entomol. 2002;95(4):722–8.

Gill RJ, Raine NE. Chronic impairment of bumblebee natural foraging behaviour induced by sublethal pesticide exposure. Funct Ecol. 2014;28:1459–71.

Gill RJ, Ramos-Rodriguez O, Raine NE. Combined pesticide exposure severely affects individual- and colony-level traits in bees. Nature. 2012;491(7422):105–8.

Girolami V, Mazzon L, Squartini A, Mori N, Marzaro M, Di Bernardo A, et al. Translocation of neonicotinoid insecticides from coated seeds to seedling guttation drops: a novel way of intoxication for bees. J Econ Entomol. 2009;102(5):1808–15.

Grimm M, Sedy K, Süβnbacher E, Riss A. Existing scientific evidence of the effects of neonicotinoid pesticides on bees. 2012. Accessed 11 Nov 2013.
Henry M, Rollin O, Aptel J, Tchamitchian S, Beguin M, Requier F, et al. A common pesticide decreases foraging success and survival in honey bees. Science. 2012;336(6079):348–50.

Higes M, Martín-Hernández R, Botías C, Bailón EG, González-Porto AV, Barrios L, et al. How natural infection by Nosema ceranae causes honeybee colony collapse. Environ Microbiol. 2008;10:2659–69.

Krupke CH, Hunt GJ, Eitzer BD, Andino G, Given K. Multiple routes of pesticide exposure for honey bees living near agricultural fields. PLoS One. 2012;7(1):e29268.

Larson JL, Redmond CT, Potter DA. Assessing insecticide hazard to bumble bees foraging on flowering weeds in treated lawns. PLoS One. 2013;8(6):e66375.

Laycock I, Cresswell JE. Repression and recuperation of brood production in Bombus terrestris bumble bees exposed to a pulse of the neonicotinoid pesticide imidacloprid. PLoS One. 2013;8(11):e79872.

Laycock I, Cotterell KC, O’Shea-Wheller TA, Cresswell JE. Effects of the neonicotinoid pesticide thiamethoxam at field-realistic levels on microcolonies of Bombus terrestris worker bumble bees. Ecotoxicol Environ Saf. 2014;100:153–8.

Lu C, Warchol KM, Callahan RA. In situ replication of honey bee colony collapse disorder. Bull Insectol. 2012;65(1):99–106.

Lu C, Warchol KM, Callahan RA. Sub-lethal exposure to neonicotinoids impaired honey bees winterization before proceeding to colony collapse disorder. Bull Insectol. 2014;67(1):125–30.

Maini S, Medrzycki P, Porrini C. The puzzle of honey bee losses: a brief review. Bull Insectol. 2010;63(1):153–60.

Mayes MA, Thompson GD, Husband B, Miles MM. Spinosad toxicity to pollinators and associated risk. Rev Environ Contam Toxicol. 2003;179:37–71.

Medrzycki P, Sgolastra F, Bortolotti L, Bogo G, Tosi S, Padovani E, et al. Influence of brood rearing temperature on honey bee development and susceptibility to poisoning by pesticides. J Apic Res. 2010;49:52–9.

Morandin LA, Winston ML, Franklin MT, Abbott VA. Lethal and sub-lethal effects of spinosad on bumble bees (Bombus impatiens Cresson). Pest Manag Sci. 2005;61(7):619–26.

Mullin CA, Frazier M, Frazier JL, Ashcraft S, Simonds R, Vanengelsdorp D, et al. High levels of miticides and agrochemicals in North American apiaries: implications for honey bee health. PLoS One. 2010;5(3):e9754.

Palmer MJ, Moffat C, Saranzewa N, Harvey J, Wright GA, Connolly CN. Cholinergic pesticides cause mushroom body neuronal inactivation in honeybees. Nat Commun. 2013;4:1634.

Pareja L, Colazzo M, Perez-Parada A, Niell S, Carrasco-Letelier L, Bseil N, et al. Detection of pesticides in active and depopulated beehives in Uruguay. Int J Environ Res Public Health. 2011;8:3844–58.

Pettis JS, vanEngelsdorp D, Johnson J, Dively G. Pesticide exposure in honey bees results in increased levels of the gut pathogen Nosema. Naturwissenschaften. 2012;99(2):153–8.

Pettis JS, Lichtenberg EM, Andree M, Stitzinger J, Rose R, Vanengelsdorp D. Crop pollination exposes honey bees to pesticides which alters their susceptibility to the gut pathogen Nosema ceranae. PLoS One. 2013;8(7):e70182.

Pilling E, Campbell P, Coulson M, Ruddle N, Tornier I. A four-year field program investigating long-term effects of repeated exposure of honey bee colonies to flowering crops treated with thiamethoxam. PLoS One. 2013;8(10):e77193.

Rondeau G, Sánchez-Bayo F, Tennekes HA, Decourtye A, Ramírez-Romero R, Desneux N. Delayed and time-cumulative toxicity of imidacloprid in bees, ants and termites. Sci Rep. 2014;4:5566.

Rossi Cde A, Roat TC, Tavares DA, Cintra-Socolowski P, Malaspina O. Effects of sublethal doses of imidacloprid in Malpighian tubules of Africanized Apis mellifera (Hymenoptera, Apidae). Microsc Res Tech. 2013;76(5):552–8.

Sandrock C, Tanadini LG, Pettis JS, Biesmeijer JC, Potts SG, Neumann P. Sublethal neonicotinoid insecticide exposure reduces solitary bee reproductive success. Agric Forest Entomol. 2014a;16:119–28.

Sandrock C, Tanadini M, Tanadini LG, Fauser-Misslin A, Potts SG, Neumann P. Impact of chronic neonicotinoid exposure on honeybee colony performance and queen supersedure. PLoS One. 2014b;9(8):e103592.

Schneider CW, Tautz J, Grünewald B, Fuchs S. RFID tracking of sublethal effects of two neonicotinoid insecticides on the foraging behavior of Apis mellifera. PLoS One. 2012;7(1):e30023.

Scholer J, Krischik V. Chronic exposure of imidacloprid and clothianidin reduce queen survival, foraging, and nectar storing in colonies of Bombus impatiens. PLoS One. 2014;9(3):e91573.

Scott-Dupree CD, Conroy L, Harris CR. Impact of currently used or potentially useful insecticides for canola agroecosystems on Bombus impatiens (Hymenoptera: Apidae), Megachile rotundata (Hymentoptera: Megachilidae), and Osmia lignaria (Hymenoptera: Megachilidae). J Econ Entomol. 2009;102(1):177–82.

Smagghe G, Deknopper J, Meeus I, Mommaerts V. Dietary chlorantraniliprole suppresses reproduction in worker bumblebees. Pest Manag Sci. 2013;69(7):787–91.

Takashi M. Reduction in homing flights in the honey bee Apis mellifera after a sublethal dose of neonicotinoid insecticides. Bull Insectol. 2013;66(1):1–9.

Tan K, Chen W, Dong S, Liu X, Wang Y, Nieh JC. Imidacloprid alters foraging and decreases bee avoidance of predators. PLoS One. 2014;9(7):e102725.

Teeters BS, Johnson RM, Ellis MD, Siegfried BD. Using video-tracking to assess sublethal effects of pesticides on honey bees (Apis mellifera L.). Environ Toxicol Chem. 2012;31(6):1349–54.

Thompson HM, Fryday SL, Harkin S, Milner S. Potential impacts of synergism in honeybees (Apis mellifera) of exposure to neonicotinoids and sprayed fungicides in crops. Apidologie. 2014;45:545–53.

Tomé HV, Martins GF, Lima MA, Campos LA, Guedes RN. Imidacloprid-induced impairment of mushroom bodies and behavior of the native stingless bee Melipona quadrifasciata anthidioides. PLoS One. 2012;7(6):e38406.

U.S. Department of Agriculture: Washington, DC. Report on the National Stakeholders Conference on Honey Bee Health 2013. Accessed 12 May 2018.

United Nations News Center report. Humans must change behaviour to save bees. 2011. Accessed 5 May 2018.

US EPA-OPP. Reregistration eligibility decision for tau-fluvalinate. 2005. Accessed 5 May 2018.

vanEngelsdorp D, Underwood RM, Caron D, Hayes J Jr. An estimate of managed colony losses in the winter of 2006-2007: a report commission by the Apiary Inspectors of America. Am Bee J. 2007;147:599–603.

vanEngelsdorp D, Hayes J Jr, Underwood RM, Pettis J. A survey of honey bee colony losses in the U. S. Fall 2007 to Spring 2008. PLoS One. 2008;3(12):e4071.

vanEngelsdorp D, Evans JD, Saegerman C, Mullin C, Haubruge E, Nguyen BK, et al. Colony collapse disorder: a descriptive study. PLoS One. 2009;4(8):e6481.

Vidau C, Diogon M, Aufauvre J, Fontbonne R, Viguès B, Brunet JL, et al. Exposure to sub-lethal doses of fipronil and thiacloprid highly increases mortality of honeybees previously infected by Nosema ceranae. PLoS One. 2011;6(6):e21550.

Whitehorn PR, O’Connor S, Goulson D, Wackers FL. Neonicotinoid pesticide reduces bumble bee colony growth and queen production. Science. 2012;336(6079):351–2.

Williams GR, Tarpy DR, vanEngelsdorp D, Chauzat MP, Cox-Foster DL, Delaplane KS, et al. Colony collapse disorder in context. Bioessays. 2010;32:845–6.

Williamson SM, Wright GA. Exposure to multiple cholinergic pesticides impairs olfactory learning and memory in honeybees. J Exp Biol. 2013;216(Pt 10):1799–807.

Williamson SM, Baker DD, Wright GA. Acute exposure to a sublethal dose of imidacloprid and coumaphos enhances olfactory learning and memory in the honeybee Apis mellifera. Invertebr Neurosci. 2013;13(1):63–70.

Williamson SM, Willis SJ, Wright GA. Exposure to neonicotinoids influences the motor function of adult worker honeybees. Ecotoxicology. 2014;23(8):1409–18.

Wu JY, Anelli CM, Sheppard WS. Sub-lethal effects of pesticide residues in brood comb on worker honey bee (Apis mellifera) development and longevity. PLoS One. 2011;6(2):e14720.

Wu JY, Smart MD, Anelli CM, Sheppard WS. Honey bees (Apis mellifera) reared in brood combs containing high levels of pesticide residues exhibit increased susceptibility to Nosema (Microsporidia) infection. J Invertebr Pathol. 2012;109(3):326–9.

Yang EC, Chuang YC, Chen YL, Chang LH. Abnormal foraging behavior induced by sublethal dosage of imidacloprid in the honey bee (Hymenoptera: Apidae). J Econ Entomol. 2008;101(6):1743–8.

1,750 Posts
Honey bee (Apis mellifera) gut microbiota promotes host endogenous detoxification capability via regulation of P450 gene expression in the digestive tract

There is growing number of studies demonstrating a close relationship between insect gut microbiota and insecticide resistance. However, the contribution of the honey bee gut microbiota to host detoxification ability has yet to be investigated. In order to address this question, we compared the expression of cytochrome P450s (P450s) genes between gut microbiota deficient (GD) workers and conventional gut community (CV) workers and compared the mortality rates and the pesticide residue levels of GD and CV workers treated with thiacloprid or tau-fluvalinate. Our results showed that gut microbiota promotes the expression of P450 enzymes in the midgut, and the mortality rate and pesticide residue levels of GD workers are significantly higher than those of CV workers. Further comparisons between tetracycline-treated workers and untreated workers demonstrated that antibiotic-induced gut dysbiosis leads to attenuated expression of P450s in the midgut. The co-treatment of antibiotics and pesticides leads to reduced survival rate and a significantly higher amount of pesticide residues in honey bees. Taken together, our results demonstrated that honey bee gut symbiont could contribute to bee health through the modification of the host xenobiotics detoxification pathways and revealed a potential negative impact of antibiotics to honey bee detoxification ability and health.

Honey bee (Apis mellifera) gut microbiota promotes host endogenous detoxification capability via regulation of P450 gene expression in the digestive tract
Yuqi Wu, Yufei Zheng, Yanan Chen, Shuai Wang, Yanping Chen, Fuliang Hu, Huoqing Zheng
Microbial Biotechnology 2020 Apr 27. doi: 10.1111/1751-7915.13579

Cytochrome P450 enzymes are the major contributors to honey bee detoxification (Berenbaum and Johnson, 2015). In the current study, we focused on the interaction of honey bee gut microbiota and honey bee endogenous detoxification enzyme. Given the important role that honey bee P450 monooxygenase enzymes play in detoxification, our study provides important insights into the functional roles of gut bacteria as well as the interac- tions between gut microbiota and host detoxification capability in the honey bee.
The midgut is one of the main sites for detoxification in insects (Smagghe and Tirry, 2001). Pesticides can be taken up by the midgutepithelial cells, where most of it is metabolized before being transported back into the midgut lumen across the apical membrane or into the haemolymph across the basal membrane (Esther et al., 2017). Our results showed that gut microbiota strongly promotes the expression of key enzymes of the honey bee xenobiotic detoxification pathway. Six of the seven honey bee P450 detoxifying enzymes were upregulated in the midgut of CV workers, suggesting that honey bee gut microbiota enhance host detoxification capability and manipulate host metabolism. This is in accordance with related researches on mammals that demonstrated the importance of microbial activity in metabolic phenotype development. Toda et al. (Toda et al., 2009) reported that most of the major CYP isozymes were highly expressed in the livers of specific-pathogen-free mice compared with germ-free mice. Claus et al. (Claus et al., 2011) found that microbiota stimulates the expression and activity of major hepatic drug-metabolizing P450s. In the meanwhile, it is quite interesting to note that the P450 expressions in the hindgut were not influenced, though most of the honey bee core gut bacteria are colonized in the hindgut instead of the midgut (Martinson et al., 2012). The results that gut microbiota only influenced the P450 expression in honey bee midguts suggests that honey bee gut microbiota may have a different effect on the different parts of the gastrointestinal tract, which may be correlated with the bacterial abundance and composition differences (Martinson et al., 2012) or the physiological differences among different compartments of the bee gut. Therefore, further studies are needed to determine which cellular mechanisms underlie the observed regulatory function of gut microbiota and to explain why the P450 expressions are only influenced in the midgut. Collectively, our findings on the expression change of P450s indicated that gut microbiota has a strong positive effect on honey bee detoxification enzyme expression, which are vital to the detoxification ability and insecticide resistance of honey bees.
Neonicotinoid insecticides are an important group of neurotoxins specifically acting as antagonists of the insect nicotinic acetylcholine receptors (Matsuda et al., 2001). Currently, neonicotinoid insecticides are consid- ered as one of the main threats to honey bee health. Many lethal and sublethal effects of neonicotinoid insecticides on bees have been described in laboratory and field studies over the past decades (Blacquiere et al., 2012; Rundlo€f et al., 2015; Tsvetkov et al., 2017).

Of all the widely used neonicotinoid insecticides, thiacloprid has relatively low toxicity to honey bees (Iwasa et al., 2004), due to the fact that CYP9Q3 can metabolize thiacloprid with high efficiency (Manjon et al., 2018). Pyrethroids exert their toxic effects by disrupting the function of voltage-gated sodium channels which are critical for electrical signalling in the nervous system (Soderlund and Bloomquist, 1989). Tau-fluvalinate, a typical pyrethroid pesticide, is widely used in honey beehives as an acaricide for the control of devastating Varroa mites. The long-term application of fluvalinate as an apicultural tool as well as its absorption by the wax in the hive have resulted in a high-level of fluvalinate residue in bee colonies all over the world (Johnson et al., 2010). Fluvalinate is considered harmless to bees under normal circumstances (Johnson et al., 2006), because members of the honey bee CYP9Q subfamily, namely CYP9Q1, CYP9Q2 and CYP9Q3can efficiently metabolize fluvalinate (Mao et al., 2011). As expected, GDT bees administered with thiacloprid displayed a dramatically increased mortality rate and a higher level of thiacloprid residues compared with CVT workers. We also found that the innoxious fluvalinate became fatal when applied to GD workers, and the fluvalinate remaining in GDT workers was significantly higher than in CVT workers.

Clearly, these findings showed that honey bee gut bacteria influence the metabolism of pesticide and confirmed that gut microbiota is crucial to honey bees for their pesticide tolerance.

Still, there are plenty of studies that showed that insect bacteria have the ability to metabolize pesticides directly (Cheng et al., 2017; Dada et al., 2019), so we conducted an in vitro experiment to examine the possibility that the gut microbiota directly detoxifies the chemical pesticides and leads to resistance. Our results showed that neither of these two pesticides were significantly degraded by honey bee whole gut cultures in vitro, suggesting that the resident honey bee gut bacteria are not likely to degrade these two pesticides. However, future works using isolated bacteria strains are needed to provide a better understanding of the direct detoxification ability of honey bee gut symbionts. Then we have co-treated CV workers with both PBO and pesticide, we found that PBO treatment significantly reduced the honey bee survival rate, which is in accordance with previous studies (Iwasa et al., 2004; Johnson et al., 2006) and provided direct evidence for the involvement of P450 enzymes in thiacloprid and fluvalinate detoxification in the presence of the microbiota. Taken together, our results revealed that honey bee gut microbiota enhances host resistance to thiacloprid and fluvalinate through the regulation of the host endogenous detoxification mechanism, instead of direct degradation of toxins by gut symbiont. In addition, considering that P450 enzymes are capable of oxidizing many different substrates (Munro et al., 2013), we believe that the contribution of gut microbiota enhanced P450 expression to honey bee pesticide resistance is not limited to these two pesticides investigated in our study.
Antibiotics have been a cornerstone of innovation in the fields of public health, agriculture and medicine. However, recent studies have shed new light on the collateral damage they impart on the indigenous host-associated communities (Modi et al., 2014). Zhan et al. (Zhan et al., 2018) revealed that the oral bioavailability of triazine herbicides was significantly increased in the rats treated with ampicillin or antibiotic ****tails, which is a consequence of the alteration of hepatic metabolic enzyme gene expression and intestinal absorption-related proteome. In apiculture, antibiotics are frequently used in bee colonies to prevent bacterial infection. Recent studies have demonstrated that antibiotic exposure can disrupt both the size and composition of the honey bee gut microbiome (Raymann et al., 2017; Raymann et al., 2018a), resulting in impaired metabolism, weakened immunity and decreased survivorship (Li et al., 2017; Raymann et al., 2017; Li et al., 2019). In our study, tetracycline, a commonly used antibiotic in bee keeping, was employed in field doses to workers. We observed a significantly decreased the community size after 5days after antibiotic treatment and a decrease in survival rate, similar to previous studies (Li et al., 2017; Raymann et al., 2017). These confirmed a successful establishment of a gut dysbiosis worker model and once again proved the detrimental effect of antibiotic on honey bee longevity.

In light of our findings above, we further evaluated whether the gut microbiota dysbiosis caused by antibiotic has a negative impact on honey bee detoxification ability, which might be a problem we will encounter in beekeeping. As predicted, our results displayed that gut microbiota dysbiosis downregulated the expression of P450s in the midgut, therefore, attenuating the honey bees’ detoxification ability. Interestingly, the expression changes of P450 in the midgut caused by the gut microbiota dysbiosis are quite different from gut microbiota deficiency, and the expression of two P450s functioning to metabolize phytochemicals (CYP6AS3 and CYP6AS4) was induced in the hindgut of AT workers. This may be due to the difference of metabolites in the gut of AT and of GD workers and suggests that honey bee gut microbiota deficiency and dysbiosis have different impacts on host physiology. The administration of both thiacloprid and fluvalinate on AT workers led to significantly increased mortality compared with that of pesticide treated NF workers. The pesticide remaining in the AT workers was significantly increased, which was probably caused by the downregulation of P450s in the midgut. These results demonstrated that the application of antibiotics interrupts the P450 expression in honey bee digestive tracts and enhances the pesticide risks for honey bees, even those of low toxicity to honey bees. The doses of pesticides we applied in this study were higher than actual field levels (38), suggesting that the combination of antibiotics and pesticides might not lead to an acute death of workers in the field colonies. Still, it is possible to hypothesize that gut dysbiosis could enhance the sublethal effects of pesticides, especially during the overwintering period when workers are exposed to antibiotics and pesticides (43) for a long period of time, and eventually lead to colony loss. However, our experiments were carried out using caged bees in a laboratory environment only, where workers have no route for acquisition of the gut microbiota and normally do not defecate. Thus, the combinatory effects of antibiotics and pesticides in field colonies remain to be determined. Moreover, it is worth studying the impact on honey bee detoxification of other chemicals (Kakumanu et al., 2016; Motta et al., 2018; Nogrado et al., 2019), that also perturb the gut microbial balance in honey bees.

Here in this study, our work revealed the interaction between honey bee gut microbiota and host resistance to pesticides for the first time. Our results showed that honey bee gut microbiota promotes the expression of detoxification enzymes in the midgut, which contribute to the host endogenous detoxification and resistance to thiacloprid and fluvalinate. These findings proved a close relationship between gut microbiota and honey bee detoxification capability, provided new insights into the honey bee host-microbiome interaction and perspectives for future studies on host-gut microbial metabolic interaction. In the current study, we have demonstrated a synergistic interaction between antibiotics and pesticides, which is detrimental for bees. And our results suggested this may be due to the reduced detoxification ability of honey bee. We were able to point out the beneficial role of a balanced gut microbiome in honey bees and provide fundamental information on how antibiotic treatment affects honey bee health.

1,750 Posts
Pesticide–Virus Interactions in Honey Bees: Challenges and Opportunities for Understanding Drivers of Bee Declines


Honey bees are key agricultural pollinators, but beekeepers continually suffer high annual colony losses owing to a number of environmental stressors, including inadequate nutrition, pressures from parasites and pathogens, and exposure to a wide variety of pesticides. In this review, we examine how two such stressors, pesticides and viruses, may interact in additive or synergistic ways to affect honey bee health. Despite what appears to be a straightforward comparison, there is a dearth of studies examining this issue likely owing to the complexity of such interactions. Such complexities include the wide array of pesticide chemical classes with different modes of actions, the coupling of many bee viruses with ectoparasitic Varroa mites, and the intricate social structure of honey bee colonies. Together, these issues pose a challenge to researchers examining the effects pesticide-virus interactions at both the individual and colony level.


(B) Pesticide exposure can negatively impact many components and pathways of the immune system. Phagocytosis: pro-hemocyte differentiation can be impaired, resulting in fewer phagocytosing immune cells. The process of phagocytosis itself can also be affected; autophagy: Regulation of autophagy can be disrupted, potentially leading to apoptosis in cells; receptor activity: some insecticides target receptors that are also involved in antiviral defenses; gene expression: pesticides can alter expression of immune and detoxification genes. This includes upregulating inhibitors of the important immune system transcription factor, NF-κB; heat shock proteins: some pesticides downregulate expression of genes coding for heat shock proteins. These proteins can reduce viral load and also have functions in the RNAi antiviral pathway; gut bacteria: pesticides can also disrupt gut microbial communities, which are known to play roles in honey bee health and immunity.

Harwood, G.P.; Dolezal, A.G. Pesticide–Virus Interactions in Honey Bees: Challenges and Opportunities for Understanding Drivers of Bee Declines. Viruses 2020, 12, 566.

1,750 Posts
Chronic within-hive video recordings detect altered nursing behaviour and retarded larval development of neonicotinoid treated honey bees

Risk evaluations for agricultural chemicals are necessary to preserve healthy populations of honey bee colonies. Field studies on whole colonies are limited in behavioural research, while results from lab studies allow only restricted conclusions on whole colony impacts. Methods for automated long-term investigations of behaviours within comb cells, such as brood care, were hitherto missing.

In the present study, we demonstrate an innovative video method that enables within-cell analysis in honey bee (Apis mellifera) observation hives to detect chronic sublethal neonicotinoid effects of clothianidin (1 and 10 ppb) and thiacloprid (200 ppb) on worker behaviour and development.

In May and June, colonies which were fed 10 ppb clothianidin and 200 ppb thiacloprid in syrup over three weeks showed reduced feeding visits and duration throughout various larval development days (LDDs). On LDD 6 (capping day) total feeding duration did not differ between treatments.

Behavioural adaptation was exhibited by nurses in the treatment groups in response to retarded larval development by increasing the overall feeding timespan. Using our machine learning algorithm, we demonstrate a novel method for detecting behaviours in an intact hive that can be applied in a versatile manner to conduct impact analyses of chemicals, pests and other stressors.

Siefert, P., Hota, R., Ramesh, V. et al. Chronic within-hive video recordings detect altered nursing behaviour and retarded larval development of neonicotinoid treated honey bees. Sci Rep 10, 8727 (2020).

1,750 Posts

Sublethal acetamiprid doses negatively affect the lifespans and foraging behaviors of honey bee (Apis mellifera L.) workers

• Effects of sublethal acetamiprid doses on the foraging behaviors of Apis mellifera worker bees were firstly investigated using the RFID system under natural swarm conditions.

• Worker bees exposed to 2 μg/bee acetamiprid will induce precocious foraging activity and shortened the lifespan.

• Worker bees exposed to 2 μg/bee acetamiprid heavily decreased the workload throughout their lifetime.

• Excessive day-off rotation of worker bees exposed to 2 μg/bee acetamiprid is firstly reported.

The neonicotinoid insecticide acetamiprid is applied widely for pest control in agriculture production. However, little is known about the effects of acetamiprid on the foraging behavior of nontarget pollinators. This study aims to investigate effects of sublethal acetamiprid doses on lifespans and foraging behaviors of honey bees (Apis mellifera L.) under natural swarm conditions. Newly emerged worker bees of each treatment received a drop of 1.5 μL acetamiprid solution (containing 0, 0.5, 1, and 2 μg/bee acetamiprid, diluted by water) on the thorax respectively. Bees from 2-day-old to deadline were monitored on foraging behaviors involving the age of bee for first foraging flights, rotating day-off status and the number of foraging flights using the radio frequency identification (RFID) system. We found that acetamiprid at 2 μg/bee significantly reduced the lifespan, induced precocious foraging activity, influenced the rotating day-off status and decreased foraging flights of worker bees. The abnormal behaviors of worker bees may be associated with a decline in lifespan. This work may provide a new perspective into the neonicotinoids that accelerate the colony failure.

Sublethal acetamiprid doses negatively affect the lifespans and foraging behaviors of honey bee (Apis mellifera L.) workers
Jingliang Shi et al., Science of The Total Environment, online 3 June 2020, 139924,

1,750 Posts
Interaction of Varroa destructor and Sublethal Clothianidin Doses during the Larval Stage on Subsequent Adult Honey Bee (Apis mellifera L.) Health, Cellular Immunity, Deformed Wing Virus Levels and Differential Gene Expression

Abstract: Honeybees (Apis mellifera L.) are exposed to many parasites, but little is known about interactions with abiotic stressors on their health, particularly when affected as larvae. Larvae were exposed singly and in combination to the parasitic mite Varroa destructor and three sublethal doses of the neonicotinoid insecticide clothianidin to evaluate their effects on survivorship, weight, haemocyte counts, deformed wing virus (DWV) levels and gene expression of the adult bees that subsequently developed. Clothianidin significantly reduced bee weight at the highest dose and was associated with an increase in haemocyte counts at the lowest dose, whereas V. destructor parasitism increased DWV levels, reduced bee emergence, lowered weight and reduced haemocyte counts. An interaction between the two stressors was observed for weight at emergence. Among the differentially expressed genes (DEGs), V. destructor infestation resulted in broader down-regulatory effects related to immunity that was often shared with the combined stressors, while clothianidin resulted in a broader up-regulatory effect more related to central metabolic pathways that was often shared with the combined stressors. Parasites and abiotic stressors can have complex interactions, including additive effects on reduced weight, number of up-regulated DEGs and biological pathways associated with metabolism.

However, the combination of V. destructor with clothianidin had additional effects observed on bee weight and the number of DEGs compared to the stressors alone. Thus, it appears that the combined stressors are able to have long-term effects on gene regulation, potentially affecting a broad range of biological pathways, which could affect the ability of the bees to metabolize and detoxify the neurotoxin, repair tissue damage or fight off infections like DWV that are essential for development and survival.

Morfin, N.; Goodwin, P.H.; Guzman-Novoa, E. Interaction of Varroa destructor and Sublethal Clothianidin Doses during the Larval Stage on Subsequent Adult Honey Bee (Apis mellifera L.) Health, Cellular Immunity, Deformed Wing Virus Levels and Differential Gene Expression. Microorganisms 2020, 8, 858.

1,750 Posts
Determination of Acute Lethal Doses of Acetamiprid and Cypermethrin for the Native Bee Apis mellifera (Hymenoptera: Apidae) in Cameroon

Honey bees are important pollinators and are essential in agriculture; as such they get exposed to a wide range of pesticides while foraging in contaminated fields or during the spray of chemical on crops. It is therefore important to know the toxicity and evaluate the impacts of bees’ exposure to these molecules. Acetamiprid and cypermethrin are two pesticides widely used in Cameroon and other countries. The objective of this study was to determine the toxicity of acetamiprid and cypermethrin on the native subspecies of Apis mellifera L. in agricultural areas in Adamaoua-Cameroon and to evaluate the impact on honeybee foragers exposed to lethal and sublethal doses of these two insecticides. The results obtained in laboratory conditions show that acetamiprid and cypermethrin are toxic to A. mellifera. The symptoms of neurotoxicity and first mortality appear 15 min after the ingestion of the high concentrations and about 30 to 45 min after the inoculation of the pesticides through contact route and the mortality increases with the concentration and time. The LC50 of acetamiprid obtained after 24 h are respectively 5.26 ng/μl for the topical application and 4.70 μg/μl by the oral route. At the same time, the LC50 of cypermethrin are respectively 2.27 ng/μl for topical application and 2.68 ng/μl for oral toxicity. For a sustainable agriculture and beekeeping, it is, therefore, important to establish quality measures on these insecticides in the ecosystem and to set up a phyto-pharmacovigilance and awareness system to the population.

Mazi, S., Vroumsia, T., Yahangar, M.-N., Malla, M. and Zroumba, D. (2020) Determination of Acute Lethal Doses of Acetamiprid and Cypermethrin for the Native Bee Apis mellifera (Hymenoptera: Apidae) in Cameroon. Open Journal of Ecology, 10, 404-417.
181 - 200 of 212 Posts