Introduction de jachères florales en zones de grandes cultures : comment mieux concilier agriculture, biodiversité et apiculture ?

Les abeilles au sens large représentent plus de 20 000 espèces dans le monde. Or, un déclin des populations d'abeilles a été récemment observé en Europe (Biesmeijer et al., 2006 ; Rasmont et al., 2006). Il pose le problème du risque de disparition de ces insectes auxiliaires et de sa répercussion sur les activités humaines qui leur sont liées comme l’apiculture, la production de fruits, de légumes, de semences. La FAO (Nations-Unies) a lancé, en 1996, un cri d’alarme à l’attention de tous les gouvernements pour sauvegarder cette faune d’auxiliaires. Les causes possibles de ce déclin sont multiples (Kearns et al., 1998 ; Ghazoul, 2005). Les plus citées concernent la destruction et la fragmentation de l’habitat des abeilles (Richards, 2001 ; Steffan-Dewenter et al., 2006) et l'impact des produits phytopharmaceutiques (Kevan, 1975 ; Johansen et al., 1983 ; Taséi, 1996 ; Haskell et McEwen, 1998)

Sublethal effects of fipronil on the ability of honeybees (Apis mellifera L.) to orientate in a complex maze

contribution to session IVTest methodology Background: The recent fipronil-based pesticide is accused by bee-keepers of causing depopulations in hives of honeybees (Apis mellifera L.). Behavioural effects during the flight of foraging honeybees would have been evoked. To test whether the insecticide fipronil may disorientate foragers, its impact on orientation in a maze was examined. Bees had to fly through a sequence of boxes to reach the target, which was a feeder containing a reward of sugar solution. After being trained to associate a green mark with the reward, foragers received 1 μg kg-1 fipronil orally and their capacity to orientate through the maze following the colour mark was tested and compared to control. Results: The rate of foragers entering the maze, and so responding to the mark placed at the entrance, was reduced with fipronil-fed animals. Before and after treatment, 86-89% of bees equally flew through the whole path and arrived to the goal without mistakes. The rate of fipronil-treated bees finding path without mistakes decreased to 60%. Conversely, the rate of bees with unsuccessful searches for the goal notably increased with treatment (34% in treated bees versus 4% in control bees). Conclusion: Our results show that orientation capacities of foragers in a complex maze were affected by fipronil. Keywords: Apis mellifera L., pesticide, maze, conditioning, visual learning, flight

The homing flight method to assess the effect of sublethal doses of plant protection products on the honey bee in field conditions: results of the ring tests

The evaluation of the potential effects of plants protection products on honeybee behavior is considered as part of the risk assessment according to Regulation (EC) No 1107/2009 and the EFSA Guidance document (EFSA 2013). But no standardized and validated method is still available. With current revisions of plant protection product risk assessment on the honeybee, a European ring test is conducted since 2015 with 11 voluntary laboratories to test a methodology assessing the effects of sublethal doses of a plant protection product administered in controlled conditions on the homing capacity of forager bees in the field. Homing success is measured by monitoring free-ranging honey bees with radio-frequency identification (RFID) tagging technology

RFID Tracking of Sublethal Effects of Two Neonicotinoid Insecticides on the Foraging Behavior of Apis mellifera

The development of insecticides requires valid risk assessment procedures to avoid causing harm to beneficial insects and especially to pollinators such as the honeybee Apis mellifera. In addition to testing according to current guidelines designed to detect bee mortality, tests are needed to determine possible sublethal effects interfering with the animal's vitality and behavioral performance. Several methods have been used to detect sublethal effects of different insecticides under laboratory conditions using olfactory conditioning. Furthermore, studies have been conducted on the influence insecticides have on foraging activity and homing ability which require time-consuming visual observation. We tested an experimental design using the radiofrequency identification (RFID) method to monitor the influence of sublethal doses of insecticides on individual honeybee foragers on an automated basis. With electronic readers positioned at the hive entrance and at an artificial food source, we obtained quantifiable data on honeybee foraging behavior. This enabled us to efficiently retrieve detailed information on flight parameters. We compared several groups of bees, fed simultaneously with different dosages of a tested substance. With this experimental approach we monitored the acute effects of sublethal doses of the neonicotinoids imidacloprid (0.15–6 ng/bee) and clothianidin (0.05–2 ng/bee) under field-like circumstances. At field-relevant doses for nectar and pollen no adverse effects were observed for either substance. Both substances led to a significant reduction of foraging activity and to longer foraging flights at doses of ≥0.5 ng/bee (clothianidin) and ≥1.5 ng/bee (imidacloprid) during the first three hours after treatment. This study demonstrates that the RFID-method is an effective way to record short-term alterations in foraging activity after insecticides have been administered once, orally, to individual bees. We contribute further information on the understanding of how honeybees are affected by sublethal doses of insecticides

Use of an innovative T-tube maze assay and the proboscis extension response assay to assess sublethal effects of GM products and pesticides on learning capacity of the honey bee Apis mellifera L.

Transgenic Cry1Ac+CpTI cotton (CCRI41) is a promising cotton cultivar throughout China but side effects and especially sublethal effects of this transgenic cultivar on beneficial insects remain poorly studied. More specifically potential sublethal effects on behavioural traits of the honey bee Apis mellifera L. have not been formally assessed despite the importance of honey bees for pollination. The goal of our study was to assess potential effects of CCRI41 cotton pollen on visual and olfactory learning by honey bees. After a 7-day oral chronic exposure to honey mixed with either CCRI41 pollen, imidacloprid-treated conventional pollen (used as positive sublethal control) or conventional pollen (control), learning performance was evaluated by the classical proboscis extension reflex (PER) procedure as well as a T-tube maze test. The latter assay was designed as a new device to assess potential side effects of pesticides on visual associative learning of honey bees. These two procedures were complementary because the former focused on olfactory learning while the latter was involved in visual learning based on visual orientation ability. Oral exposure to CCRI41 pollen did not affect learning capacities of honey bees in both the T-tube maze and PER tests. However, exposure to imidacloprid resulted in reduced visual learning capacities in T-tube maze evaluation and decreased olfactory learning performances measured with PER. The implications of these results are discussed in terms of risks of transgenic CCRI41 cotton crops for honey bees

What's Killing American Honey Bees?

American beekeepers reported unusually high rates of colony loss in early 2007 as bees broke from their overwintering clusters. Researchers are struggling to explain what's behind this mysterious disappearance, called colony collapse disorder

3.5 The homing flight ring test: method for the assessment of sublethal doses of plant protection products on the honey bee in field conditions

International audienc

Detection of Pesticides in Active and Depopulated Beehives in Uruguay

The influence of insecticides commonly used for agricultural purposes on beehive depopulation in Uruguay was investigated. Honeycombs, bees, honey and propolis from depopulated hives were analyzed for pesticide residues, whereas from active beehives only honey and propolis were evaluated. A total of 37 samples were analyzed, representing 14,800 beehives. In depopulated beehives only imidacloprid and fipronil were detected and in active beehives endosulfan, coumaphos, cypermethrin, ethion and chlorpyrifos were found. Coumaphos was present in the highest concentrations, around 1,000 μg/kg, in all the propolis samples from active beehives. Regarding depopulated beehives, the mean levels of imidacloprid found in honeycomb (377 μg/kg, Standard Deviation: 118) and propolis (60 μg/kg, Standard Deviation: 57) are higher than those described to produce bee disorientation and fipronil levels detected in bees (150 and 170 μg/kg) are toxic per se. The other insecticides found can affect the global fitness of the bees causing weakness and a decrease in their overall productivity. These preliminary results suggest that bees exposed to pesticides or its residues can lead them in different ways to the beehive