Sub-lethal effects of imidacloprid on bumblebees, Bombus terrestris (Hymenoptera: Apidae), during a laboratory feeding test.-

Abstract: A laboratory feeding test was conducted on queenless micro-colonies of three bumblebee workers (Bombus terrestris L) to study the effects of low doses of imidacloprid on pollen and syrup consumption, worker survival, brood size and larval development. Two doses were used: D1 = 10 mg AI kg À1 in syrup and 6 mg AI kg À1 in pollen; D2 was 2.5 times higher in syrup and 2.7 higher in pollen. During 85 days 27, 30 and 29 micro-colonies were reared for control, D1 and D2 treatments respectively. Food consumption was not affected by either dose. During the 5-day pre-oviposition period the mean insecticide intake was 4.8 ng per day per worker in treatment D2. Both doses slightly but signi®cantly affected worker survival rate by 10% during the ®rst month, without any dose-effect relationship. Brood production was signi®cantly reduced in D1 treatment and larval ejection by workers was signi®cantly lower in D1 and D2 than in control. No signi®cant effect of D1 and D2 treatments on the duration of larval development was revealed. No residue could be detected in workers still alive after 85 days. It was concluded that the survival rate and reproductive capacity of B terrestris was not likely to be affected by prolonged ingestion of nectar produced by sun¯ower after seed-dressing treatment with imidacloprid (Gaucho), since honey or pollen collected by honeybees foraging treated sun¯ower never revealed concentrations of imidacloprid higher than 10 mg kg À1

Honey bee brood ring-test: method for testing pesticide toxicity on honeybee brood in laboratory conditions

contribution to session IV Test methodology The Experimental unit of entomology (INRA, France) developed a new in vitro method to assess effects of pesticides on honey bee larvae. The method consists in rearing bee larvae in plastic cells. The larvae are fed with diet containing 50% of fresh royal jelly and 50% of an aqueous sugar and yeast extract solution, and reared in an incubator at 35 °C and 96% relative humidity. According to that method, 9 tests (7 in 2008 and 2 in 2005) were carried out in 7 laboratories and different countries. The objective of these trials was to assess the LD50 for dimethoate 48 hours after an acute exposure. The LD50 values ranged from 1.5 μg a.i./larva to 8.8 μg a.i./larva, with 2 tests with particularly high values (5.0 and 8.8 μg a.i./larva). In 7 tests, these values ranged from 1.5 μg a.i./larva to 3.1 μg a.i./larva. Such variability may be due to the colony origin, the season and larva heterogeneity at grafting. Solutions are proposed to improve the method through the continuation of the ring test. Keywords: Apis mellifera, brood, in vitro test, dimethoat

Impact des pesticides sur les Abeilles et les autres pollinisateurs

International audienceLes abeilles domestiques sont surtout connues par les produits de la ruche, miel, pollen, cire, etc., mais le rôle d'auxiliaire de l'agriculture de ces insectes est mis en avant beaucoup plus rarement. Quant aux autres espèces appartenant au même grand groupe des mellifères, comme disaient les auteurs anciens, c'est-à-dire les Bourdons et tout le cortège des Abeilles non sociales, a-t-on une idée de la taille de leur population et de leur action sur les plantes cultivées ? II faut savoir que chez bon nombre d'entre elles, l'intensité et la qualité du transfert de pollen d'une fleur à l'autre est un facteur du rendement au même titre que les éléments nutritifs, l'eau, la température... L'importance du facteur pollinisation, bien que reconnue, est assez difficile à chiffrer. Elle apparaît d'une façon aiguë dans les cas de réduction subite et de disparition accidentelle de la faune pollinisatrice dans les zones où l'on cultive des plantes à gros besoins de pollinisation. Naturellement, des expérimentations comparatives où l'on exclut les insectes butineurs de certaines plantes fournissent des données irréfutables sur l'action des pollinisateurs. Quelles sont donc les cultures entomophiles, c'est-à-dire celles qui bénéficient de la visite d'insectes mellifères ? Il faut citer cinq grands groupes de plantes entomophiles cultivées : les arbres fruitiers (pommier, poirier, cerisier, kiwi, prunier, amandier, pêcher, châtaignier), les « petits fruits » (fraisier, framboisier, cassissier, groseillier), les oléagineux (tournesol et colza), les légumes (melon, tomate), les productions de graines et semences (luzerne, trèfle violet, trèfle blanc, féverole), les semences légumières (carotte, oignon, etc.). Les bénéfices apportés par les auxiliaires pollinisateurs sont variables selon l'espèce considérée et selon la variété. En 1982, la valeur des productions entomophiles pouvait être estimée à 27 milliards de francs et la part qui revenait aux insectes pollinisateurs à 12%, soit environ 3 milliards, ce qui représente d'après Borneck et Bricout (1984) les exportations françaises de cognac ou bien le tiers des exportations annuelles de blé

Effects of insect growth regulators on honey bees and non-Apis bees. A review

The insect growth regulators (IGRs) are ecdysone or juvenile hormone mimics, or chitin synthesis inhibitors. They are more likely to be hazardous to larval insects than to adults. Application of JH mimics to adult honey bees may affect foraging behaviour and some physiological traits. Topical and feeding tests revealed that application of IGRs to larvae may result in death and larval ejection by workers, malformed larvae and pupae with typical rimmed eyes, or malformed adults. Several laboratory "larvae tests" using artificially contaminated diets have been described for honey bees and bumble bees. Field and cage methods have also been published for honey bees and bumble bees respectively. Diflubenzuron was generally safe for honey bee brood in fields treated at 35 to 400 g$\cdot$ha$^{-1}$ a.i. and harmful to bumble bees at 300 g$\cdot$ha$^{-1}$ a.i. Fenoxycarb was safe for bumble bees at 1200 g$\cdot$ha$^{-1}$ a.i. and hazardous to honey bees causing damage to honey bee brood at 140 g$\cdot$ha$^{-1}$

Effects of insect growth regulators on honey bees and non-Apis bees. A review

The insect growth regulators (IGRs) are ecdysone or juvenile hormone mimics, or chitin synthesis inhibitors. They are more likely to be hazardous to larval insects than to adults. Application of JH mimics to adult honey bees may affect foraging behaviour and some physiological traits. Topical and feeding tests revealed that application of IGRs to larvae may result in death and larval ejection by workers, malformed larvae and pupae with typical rimmed eyes, or malformed adults. Several laboratory "larvae tests" using artificially contaminated diets have been described for honey bees and bumble bees. Field and cage methods have also been published for honey bees and bumble bees respectively. Diflubenzuron was generally safe for honey bee brood in fields treated at 35 to 400 g$\cdot$ha$^{-1}$ a.i. and harmful to bumble bees at 300 g$\cdot$ha$^{-1}$ a.i. Fenoxycarb was safe for bumble bees at 1200 g$\cdot$ha$^{-1}$ a.i. and hazardous to honey bees causing damage to honey bee brood at 140 g$\cdot$ha$^{-1}$

OBSERVATIONS PRÉLIMINAIRES SUR LA BIOLOGIE D'OSMIA (CHALCOSMIA) CŒRULESCENS L., (HYMENOPTERA MEGACHILIDAE), POLLINISATRICE DE LA LUZERNE (MEDICAGO SATIVA L.)

International audienc

LE COMPORTEMENT DE NIDIFICATION CHEZ OSMIA (OSMIA) CORNUTA LATR. ET OSMIA (OSMIA) RUFA L. (HYMENOPTERA MEGACHILIDAE)

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PREMIÈRES OBSERVATIONS SUR LA POLLINISATION ET LA COULURE DES FLEURS DE LUZERNE EN CHARENTES (MEDICAGO SATIVA L.)

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