Luc Belzunces

Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement

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Jean‐Luc Brunet

Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement

Sylvie Tchamitchian

Département Environnement et Agronomie

Marianne Cousin

Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement

André Kretzschmar

University of Zurich

Yves Le Conte

Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement

Séverine Suchail

Institut Méditerranéen de Biodiversité et d'Ecologie Marine et Continentale

Guillaume Kairo

Département Environnement et Agronomie

Cédric Alaux

Association pour l'Utilisation du Rein Artificiel dans la région Lyonnaise

Marc Bonnet

Centre Hospitalier Annecy Genevois

Yvan Capowiez

Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement

Cooperative Institutions

Centre National de la Recherche Scientifique

Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement

Institut National de la Recherche Agronomique

AgroParisTech

Université d'Avignon et des Pays de Vaucluse

Association pour l'Utilisation du Rein Artificiel dans la région Lyonnaise

Université Claude Bernard Lyon 1

Département Environnement et Agronomie

Université Clermont Auvergne

Clermont Université

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Chronic toxicity and physiological changes induced in the honey bee by the exposure to fipronil and Bacillus thuringiensis spores alone or combined

Ecotoxicology and Environmental Safety (2016)

Maria Teresa Renzi Marcel Amichot David Pauron Sylvie Tchamitchian Jean‐Luc Brunet

Fipronil

Bacillus thuringiensis

10.1016/j.ecoenv.2016.01.028

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Citations (55)

DISCREPANCY BETWEEN ACUTE AND CHRONIC TOXICITY INDUCED BY IMIDACLOPRID AND ITS METABOLITES IN APIS MELLIFERA

Environmental Toxicology and Chemistry (2001)

Séverine Suchail David Guez Luc Belzunces

Imidacloprid is a systemic nitroguanidine insecticide that belongs to the neonicotinoid family. As an agonist of the acetylcholine receptor, it attacks the insect nervous system and is extremely effective against various sucking and mining pests. Oral acute and chronic toxicity of imidacloprid and its main metabolites (5-hydroxyimidacloprid, 4,5-dihydroxyimidacloprid, desnitroimidacloprid, 6-chloronicotinic acid, olefin, and urea derivative) were investigated in Apis mellifera. Acute intoxication by imidacloprid or its metabolites resulted in the rapid appearance of neurotoxicity symptoms, such as hyperresponsiveness, hyperactivity, and trembling and led to hyporesponsiveness and hypoactivity. For acute toxicity tests, bees were treated with doses of toxic compounds ranging from 1 to 1,000 ng/bee (10-10,000 microg/kg). Acute toxicity (LD50) values of imidacloprid were about 60 ng/bee (600 microg/kg) at 48 h and about 40 ng/bee (400 microg/kg) at 72 and 96 h. Out of the six imidacloprid metabolites tested, only two (5-hydroxyimidacloprid and olefin) exhibited a toxicity close to that of imidacloprid. Olefin LD50 values were lower than those of imidacloprid. The 5-hydroxyimidacloprid showed a lower toxicity than imidacloprid with a LD50 four to six times higher than that of imidacloprid. Urea also appeared as a compound of nonnegligible toxicity by eliciting close to 40% mortality at 1,000 ng/bee (10,000 microg/kg). However, no significant toxicity was observed with 4,5-dihydroxyimidacloprid, 6-chloronicotinic acid, and desnitroimidacloprid in the range of doses tested. To test chronic toxicity, worker bees were fed sucrose solutions containing 0.1, 1, and 10 microg/L of imidacloprid and its metabolites for 10 d. Fifty percent mortality was reached at approximately 8 d. Hence, considering that sucrose syrup was consumed at the mean rate of 12 microl/d and per bee, after an 8-d period the cumulated doses were approximately 0.01, 0.1, and 1 ng/bee (0.1, 1, and 10 microg/kg). Thus, all tested compounds were toxic at doses 30 to 3,000 (olefin), 60 to 6,000 (imidacloprid), 200 to 20,000 (5-OH-imidacloprid), and >1,000 to 100,000 (remaining metabolites) times lower than those required to produce the same effect in acute intoxication studies. For all products tested, bee mortality was induced only 72 h after the onset of intoxication.

Neonicotinoid

Chronic toxicity

Median lethal dose

10.1897/1551-5028(2001)020<2482:dbaact>2.0.co;2

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Exposure of larvae to thiamethoxam affects the survival and physiology of the honey bee at post-embryonic stages

Environmental Pollution (2017)

Daiana Antonia Tavares Claudia Dussaubat André Kretzschmar Stephan Malfitano Carvalho Elaine C.M. Silva-Zacarín

Carboxylesterase

10.1016/j.envpol.2017.05.092

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Interactions between Nosema microspores and a neonicotinoid weaken honeybees (Apis mellifera)

Environmental Microbiology (2009)

Cédric Alaux Jean‐Luc Brunet Claudia Dussaubat Fanny Mondet Sylvie Tchamitchan

Summary Global pollinators, like honeybees, are declining in abundance and diversity, which can adversely affect natural ecosystems and agriculture. Therefore, we tested the current hypotheses describing honeybee losses as a multifactorial syndrome, by investigating integrative effects of an infectious organism and an insecticide on honeybee health. We demonstrated that the interaction between the microsporidia Nosema and a neonicotinoid (imidacloprid) significantly weakened honeybees. In the short term, the combination of both agents caused the highest individual mortality rates and energetic stress. By quantifying the strength of immunity at both the individual and social levels, we showed that neither the haemocyte number nor the phenoloxidase activity of individuals was affected by the different treatments. However, the activity of glucose oxidase, enabling bees to sterilize colony and brood food, was significantly decreased only by the combination of both factors compared with control, Nosema or imidacloprid groups, suggesting a synergistic interaction and in the long term a higher susceptibility of the colony to pathogens. This provides the first evidences that interaction between an infectious organism and a chemical can also threaten pollinators, interactions that are widely used to eliminate insect pests in integrative pest management.

Neonicotinoid

10.1111/j.1462-2920.2009.02123.x

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Citations (533)

ALTERATION OF THE HOMING-FLIGHT IN THE HONEY BEE APIS MELLIFERA L. EXPOSED TO SUBLETHAL DOSE OF DELTAMETHRIN

Environmental Toxicology and Chemistry (1995)

Rémy Vandame M. Meled Mélanie Colin Luc Belzunces

Homing (biology)

10.1897/1552-8618(1995)14[855:aothit]2.0.co;2

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Citations (83)

A Pragmatic Approach to Assess the Exposure of the Honey Bee (Apis mellifera) When Subjected to Pesticide Spray

PLoS ONE (2014)

Yannick Poquet Laurent Bodin Marc Tchamitchian Marion Fusellier Barbara Giroud

Plant protection spray treatments may expose non-target organisms to pesticides. In the pesticide registration procedure, the honey bee represents one of the non-target model species for which the risk posed by pesticides must be assessed on the basis of the hazard quotient (HQ). The HQ is defined as the ratio between environmental exposure and toxicity. For the honey bee, the HQ calculation is not consistent because it corresponds to the ratio between the pesticide field rate (in mass of pesticide/ha) and LD50 (in mass of pesticide/bee). Thus, in contrast to all other species, the HQ can only be interpreted empirically because it corresponds to a number of bees/ha. This type of HQ calculation is due to the difficulty in transforming pesticide field rates into doses to which bees are exposed. In this study, we used a pragmatic approach to determine the apparent exposure surface area of honey bees submitted to pesticide treatments by spraying with a Potter-type tower. The doses received by the bees were quantified by very efficient chemical analyses, which enabled us to determine an apparent surface area of 1.05 cm2/bee. The apparent surface area was used to calculate the exposure levels of bees submitted to pesticide sprays and then to revisit the HQ ratios with a calculation mode similar to that used for all other living species. X-tomography was used to assess the physical surface area of a bee, which was 3.27 cm2/bee, and showed that the apparent exposure surface was not overestimated. The control experiments showed that the toxicity induced by doses calculated with the exposure surface area was similar to that induced by treatments according to the European testing procedure. This new approach to measure risk is more accurate and could become a tool to aid the decision-making process in the risk assessment of pesticides.

Hazard quotient

10.1371/journal.pone.0113728

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Citations (38)

Three‐dimensional trajectories of ⁶⁰Co‐labelled earthworms in artificial cores of soil

European Journal of Soil Science (2001)

Yvan Capowiez Pierre Renault Luc Belzunces

Summary Information on earthworm burrowing behaviour is scarce and therefore the evolution of the macroporosity related to earthworm activities is still poorly known. We have designed a new apparatus, ‘Colonne Gamma’, to follow the three‐dimensional trajectories of radio‐labelled earthworms in artificial cores of soil. Earthworms are radio‐labelled by injecting into their coelomic cavity a small source of 60 Co (volume 0.1 mm 3 , intensity 13.5 μCi). The emission of gamma rays is recorded by three detectors carried by a disc that oscillates vertically around the soil core where the earthworm is introduced. We have also developed a deterministic model to estimate the positions of the 60 Co source from the number of gamma rays received by each detector during an oscillation. Numerical experiments showed that the uncertainties of estimates were less than 3 mm for each coordinate. To validate the results, we tracked the trajectory (one position every 4 minutes) of a radio‐labelled earthworm for 1 week and compared it with the skeleton of the macroporosity obtained by computer assisted tomography of the same soil core. There was a general qualitative agreement between the trajectory and the skeleton. Moreover, based on the precise study of the successive positions of the earthworm we could distinguish two different kinds of activities in the trajectory: displacement and digging events. The ‘Colonne Gamma’ apparatus therefore has great potential for studies of the ecology and the behaviour of earthworms.

Oligochaeta (plant)

Digging

Burrow

10.1046/j.1365-2389.2001.00384.x

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Citations (23)

3D reconstruction and quantification of macropores using X-ray computed tomography and image analysis

Geoderma (2002)

Alain Pierret Yvan Capowiez Luc Belzunces C.J. Moran

Macropore

10.1016/s0016-7061(01)00127-6

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Citations (257)

Seasonal variations in susceptibility of Apis mellifera to the synergistic action of prochloraz and deltamethrin

Environmental Toxicology and Chemistry (1998)

Maggy Meled Andreas Thrasyvoulou Luc Belzunces

Abstract The synergistic action of prochloraz and deltamethrin was investigated in summerand winter bees. Prochloraz and deltamethrin were used at sublethal doses that did not induce any significant mortality. Bees were treated with different doses of deltamethrin, either alone or in combination with prochloraz, at the constant field rate of 25 g/ha. In summer bees, the combination of prochloraz and deltamethrin at 125 mg/ha triggered a synergy that produced approx. 63 ± 5% mortality (corrected) after 24 h. At 62.5 mg/ha, deltamethrin still acted in synergy with prochloraz by inducing about 32.5 ± 3.5% mortality (corrected) after 24 h. The field rate of 31.25 mg/ha was the lowest dose at which deltamethrin acted in synergy with prochloraz in summer bees. In winter bees, no synergy occurred between prochloraz and deltamethrin at doses of 125 and 250 mg/ha. The deltamethrin dose had to be increased to 500 mg/ha to observe a synergy that produced only 47 ± 11.7% mortality (corrected) after 24 h. Considering the deltamethrin doses at which synergy occurred, summer bees appeared to be approximately eightfold more susceptible than winter bees to the synergistic action of prochloraz and deltamethrin.

10.1002/etc.5620171220

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Citations (65)

Mild chronic exposure to pesticides alters physiological markers of honey bee health without perturbing the core gut microbiota

Scientific Reports (2022)

Hanine Almasri Joanito Liberti Jean‐Luc Brunet Philipp Engel Luc Belzunces

Abstract Recent studies highlighted that exposure to glyphosate can affect specific members of the core gut microbiota of honey bee workers. However, in this study, bees were exposed to relatively high glyphosate concentrations. Here, we chronically exposed newly emerged honey bees to imidacloprid, glyphosate and difenoconazole, individually and in a ternary mixture, at an environmental concentration of 0.1 µg/L. We studied the effects of these exposures on the establishment of the gut microbiota, the physiological status, the longevity, and food consumption of the host. The core bacterial species were not affected by the exposure to the three pesticides. Negative effects were observed but they were restricted to few transient non-core bacterial species. However, in the absence of the core microbiota, the pesticides induced physiological disruption by directly altering the detoxification system, the antioxidant defenses, and the metabolism of the host. Our study indicates that even mild exposure to pesticides can directly alter the physiological homeostasis of newly emerged honey bees and particularly if the individuals exhibit a dysbiosis (i.e. mostly lack the core microbiota). This highlights the importance of an early establishment of a healthy gut bacterial community to strengthen the natural defenses of the honey bee against xenobiotic stressors.

Dysbiosis

Hormesis

10.1038/s41598-022-08009-2

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Citations (44)