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Dossier thématique : l'Abeille; National audience; Si nous voulions que l’Abeille fût indicatrice, au sens d’indicateur écologique, de quelque chose qui regarde l’humanité, par exemple de sa responsabilité vis-à-vis de la planète, eh bien nous sommes servis ! La recherche occidentale est aujourd’hui mobilisée pour empêcher la disparition de l’Abeille qui est l’abeille apicole, l’abeille domestique, l’espèce Apis mellifera1. Et cette disparition n’est pas pensable sans celles de toutes les autres abeilles (les apiformes), puis des insectes pollinisateurs et finalement des plantes qui dépendent le plus du service écologique de la pollinisation réalisée par les insectes ! L’Abeille présente des symptômes inquiétants, mais quelle Abeille ? L’Abeille a deux figures : des populations sauvages et des populations élevées par l’humain. C’est dans les ruchers de l’apiculture que les symptômes sont décrits par les apiculteurs et en termes d’élevage (cheptel, production, état sanitaire, soins, etc.). Ses symptômes sont-ils ceux de l’ambassadrice auprès de l’humanité d’une faune sauvage menacée, ou bien ceux d’un animal d’élevage mal protégé des calamités ?

In order to test the hypothesis whether the queen can mark pheromone on the wall of the cells where the queen laid eggs, three experiments were designed and conducted. The first experiment was to transfer three kinds of eggs–queen laid diploid eggs (QD), queen laid haploid eggs (QH) and worker laid haploid eggs (WH), which came from the same colony into the cells where the queen has laid eggs and has not laid eggs respectively, then observing and counting the number of eggs remaining. The second experiment is similar to the first one, but three kinds of eggs came from the different colonies. The third experiment used only QD to investigate. The results of these experiments did not support the hypothesis that the queen can mark pheromone in the wall of the cell, but supported the viewpoints of worker policing and recognizing in the honeybee

National audience; Pour étudier l'impact des pesticides sur le comportement de l'abeille domestique, les techniques classiques n'offrent qu'un suivi simultané pour un nombre limité d'individus, et cela sur une durée d'observation de quelques heures seulement. Pourtant des outils modernes de télédétection et d'identification peuvent s'appliquer en écotoxicologie comportementale. A cet égard, les puces électroniques RFID (Radio Fréquency Identification Device) permettent de suivre automatiquement un grand nombre d'insectes, enregistrés de façon simultanée. La lecture très rapide (millisecondes) s'effectue à travers plusieurs barrières physiques (propolis, colle, plastique, bois...). Le travail mené ici montre l'intérêt de cette technique d'enregistrement du comportement individuel des abeilles avec la problématique des pesticides pouvant affecter leurs traits d'histoire de vie.

Hypopharyngeal glands (HPG) are the main organs responsible of royal jelly secretion. The size of the HPG is age2, 4 and food protein5, 7 dependent, and correlated to the amount of secretion2, and the weight of the head5. Their development can be assessed with a microscope by measuring the acini diameter after dissection.. This very useful method1, 3, 5, 6 has some inconveniences: it requires dexterity to extract the gland, and the diameter of the acini is difficult to measure because of its pear shape. In order to assess the HPG development, total protein of the gland can be measured with the Bradford method7, 8, 9, but this also requires to extract it from the head. The development of the HPG may be also affected by substances known for their insecticide effects like soybean tripsin inhibitor 8, 9. The objective of this work is to compare two methods for assessing the effects of insecticides on HGP development. The first one consists in measuring the acini diameter, and the second one in measuring the total protein of the head. The measurements are made on bee nurses intoxicated during 10 days with sublethal doses of dimethoate.

Since Varroa destructor invaded Apis mellifera populations in Europe in the seventies, this parasitism has been extensively studied, from control management ta molecular approaches of the host-parasite relationships. Chemical control of the mite was followed by c1assical events of pest management: resistance of the mite ta acaricides and pesticide residues in the wax. These events induced the set-up of biological and technical control measures of the mite. In parallel, the equilibrated parasitism of Apis cerana, a honeybee from East Asia, by Varroa destructor has been extensively studied and compared to the interaction with Apis mellifera in an attempt to understand the mechanisms underlying this host-parasite equilibrium. The knowledge of these mechanisms should have helped sort out selection criteria for Apis meflifera breeding programmes. However, despite efforts to breed Varroa resistant bees, little progress had been made. The basic biology of the mite, including chemical ecology, behavioural studies, population . dynamics and genetics, as weil as molecular responses of the honey bees, have been investigated for more than 25 years producing an impressive amount of scientific Iiterature, making the Varroa - honey bee interaction one of the most extensively studied host - parasite model systems. More recently, some natural honey bee populations have been shown to survive ta mite infestations, opening the way to the concept of integrated Varroa management. These bee populations will be particularly useful for determining the mechanisms of mite resistance in Apis mellifera. In addition, the recent sequencing of the honey bee genome should help us learn more about the molecular responses of the bees to mite parasitism. Comparative studies between resistant and susceptible bees are being developed and should be helpful to identify the genes involved in resistance. ln my talk, 1 will describe the different steps of the applied and fundamental research developed since the mite invaded Europe and conclude with a discussion of possible integrated Varroa management strategies for beekeeping

Social insects live in colonies; each colony, composed of up to hùndreds of thousands or evenmillions of individuals, called workers, behaves as a single integratedentity. A colony reproduces as a unit, and its properties are believed to result from selectionmainly at the level ofthe whole colony (25).Although social insects possess brains capable of sophisticated cognitive functions (22), it is unlikely that an individual colony member has the capacity to acquire and integrate information on the global state ofits colony and how that changes as a result of changing internaI and external conditions (28). One ofthe central problems in social insect biology, therefore, is that ofcolony integration: how the activities of thousands of individual workers are integrated to form a productive colony (37). Colony integration in the insect societies has been studied· intensively, and much has been learned about the mechanisms by which it is governed (4, 5, 32). Several different types of group decision-making activities in insect societies appear to be regulated by processes similar to quorum sensing in bacteria, includingdecisionsonnest sites (32a) and the allocation of labor to different activities.. Identifyingcommonalities · in the social behavior of social insects and microbes might provide ideas on social regulation in general. Studies of sorne species of microorganisms have revealed that the core elements of sociality-altruism and division oflabor-are possible without a brain at aIl (7,29). This chapter teviews our understanding of the regulation of division of labor in honeybee colonies from the perspective of quorum sensing.

In vivo metabolization of acetamiprid (AAP) was studied in the honeybee, Apis mellifera. The distribution of AAP and its metabolites was monitored during 72 h in six biological compartments: head, thorax, abdomen, haemolymph, midgut and rectum. Honeybees were treated orally with 100 μg of [14C]-AAP per kg of bee, a dose about 1500 times lower than the median lethal dose at 72 h. Surprisingly, after 72 h, only 40% of the total radioactivity was eliminated, suggesting that AAP and its metabolites tended to persist in the honeybee. AAP was rapidly distributed in all compartments and metabolized. Just after AAP administration, radioactivity was mainly localized in the abdomen, and then in the rectum. After 72 h, the maximal amount of radioactivity (about 20% of the ingested dose) was recovered again in the abdomen, whereas the lowest amount of total radioactivity was recovered in the haemolymph. Radioactivity in the head did not exceed 7.6% of total ingested radioactivity. More than 50% of AAP was metabolized in less than 30 min indicating a very low half-life of AAP. During the first hours, AAP was mainly detected in nicotinic acetylcholine receptor-rich tissues. Among the 7 detected metabolites, the major metabolites were the 6-choronicotinic acid and an unknown metabolite called U1, present mainly in the rectum, the thorax and the head. Our results indicated that the low toxicity of AAP is a reflection of its rapid and efficient metabolization despite of the persistence of AAP metabolites in the honeybee., La métabolisation de l’acétamipride (AAP) a été étudiée chez l’abeille Apis mellifera. Le suivi de l’AAP et des ses métaboliques est réalisé durant 72 h dans six compartiments biologiques que sont l’intestin, l’hémolymphe, le thorax, la tête, l’abdomen et le rectum. Les abeilles ont ingérées une dose 1500 fois plus faible que la Dose Létale médiane (DL50) soit 100 μg de [14C]-AAP par kg, une dose comparable à celle à la DL50 de l’imidaclopride (IMI). Le fait le plus marquant de cette étude est de retrouver plus de 60% de la dose ingérée après 72h. Toutefois, l’AAP est très rapidement distribué et métabolisé dans l’organisme. Après l’ingestion, la radioactivité retrouvée est principalement localisée dans l’abdomen puis dans le rectum. A 72 h, 20% de la dose ingérée est retrouvée au niveau de l’abdomen. L’hémolymphe est le compartiment où la présence de radioactivité est constamment la plus faible. Au niveau de la tête, la quantité de radioactivité n’excède pas 7,6% de la quantité initiale. L’AAP présente une demi-vie très faible (inférieure à 30 min.) dans l’organisme. Toutefois, l’AAP est localisé dans les premiers temps au niveau des compartiments riches en cibles principales, les récepteurs nicotiniques à l’acétylcholine. Parmi les 7 métabolites détectés, deux métabolites sont majeurs : l’acide 6-chloronicotinique et un métabolite inconnu U1. Cette étude nous permet d’affirmer que la plus faible toxicité de l’AAP par rapport à celle de l’IMI est due à une détoxication plus efficace et ce, malgré la persistance de métabolites dans l’organisme.

Egalement publié dans : Santé de l'Abeille (La), 2007 (217, 15-17 Auteurs : Le Conte Y., Crauser D., Bécard, J.M. et dans : dans Abeille de France et l'Apiculteur, 2007 (932), 26 Auteurs : Y. Le Conte, D. Crauser, J.M. Bécard; De nombreux exemples montrent qu’à terme les acariens deviennent résistants aux acaricides utilisés pour contrôler leurs populations. L’amitraze est utilisée depuis plus de 23 ans pour lutter contre le varroa et il se pose régulièrement la question de l’apparition de populations résistantes. Cet article traite de l’efficacité de cette molécule sur des populations de varroas en Avignon.

Le laboratoire de l’United States Department of Agriculture à Baton Rouge possède une renommée internationale pour la qualité et la quantité des travaux menés sur l’élevage et la sélection des abeilles. Une collaboration entre un des chercheurs de ce laboratoire, John Harbo, et l’INRA a rendu possible une visite dans cet endroit mythique de l’abeille

A l’issue du Colloque européen d’apidologie, qui s’est tenu à Udine en septembre dernier, un certain nombre de groupes de travail se sont formés, fédérant des scientifiques de différents domaines, comme la pathologie ou la sélection des abeilles.

7. ed. Mention d'édition : 7. ed.

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Computational methods in toxicology and pharmacology integrating Internet resources; International audience

Habituation of the proboscis extension reflex (PER) in honeybees (Apis mellifera) is age-dependent. Very young bees (or =7 days old) require significantly less trials to abolish the response to multiple sucrose stimulations than older bees (or =8 days old). A nicotinic agonist, imidacloprid, modifies this behaviour by increasing the number of trials inor =7-day-old bees and by decreasing it in older bees [Neurobiol. Learn. Mem. 76 (2001) 183.]. Here we tested our hypothesis that this effect is associated with a differential expression of two subtypes of nicotinic acetylcholine receptors (nAChRs). By testing the effects of six metabolites of imidacloprid, we show that two of them, olefin and 5-hydroxy-imidacloprid, modify the number of trials needed to habituate the PER in a contrasting manner. Olefin increases the number of trials in both age groups, whereas 5-hydroxy-imidacloprid decreases the number of trials, but only in 8-day-old individuals. We conclude that olefin and 5-hydroxy-imidacloprid are specific agonists of two subtypes of an nAChR that are differentially expressed during adult maturation of young honeybees. Olefin is the agonist of an nAChR expressed in both age groups, whereas 5-hydroxy-imidacloprid is the agonist of a late-onset nAChR that is activated in 8-day-old bees. The implications of this finding for the honeybee biology are discussed.

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chap. 1

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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), and1,000 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.

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