Effects of Cry1Ab protoxin, deltamethrin and imidacloprid on the foraging activity and the learning performances of the honeybee Apis mellifera, a comparative approach

Abstract

-In a comparative approach, we evaluated the effects of Cry1Ab protoxin, deltamethrin and imidacloprid insecticides on mortality, syrup consumption, foraging activity and olfactory learning capacities of free-flying honeybees. In an indoor flight cage we exposed bee colonies to different syrups containing Cry1Ab protoxin, deltamethrin or imidacloprid at 1000 µg/kg, 500 µg/kg and 48 µg/kg, respectively. Cry1Ab did not affect mortality, syrup consumption or learning capacities. However, foraging activity was reduced during and after the treatment. Deltamethrin and imidacloprid both affected syrup consumption and foraging activity. Deltamethrin also induced a reduction in learning capacities. With the tested concentrations, our study suggests that for honeybees, synthetic insecticides such as deltamethrin may induce a greater hazard than Cry1Ab protein, potentially expressed in Bt corn pollen at concentrations lower than 1000 µg/kg.Apis mellifera / Cry1Ab protoxin / insecticide / behaviour / risk assessment

Effects of Bt corn pollen on honey bees: emphasis on protocol development

“…However the minimum dose that would cause a detectable effect could not be determined due to our design comprising one hive per dose in two replicate plots. Considering contradictory conclusions on imidacloprid concentrations resulting in no chronic effect (Maus et al, 2003) or in significant effects on survival or behavior (Suchail et al, 2001;Ramirez-Romero et al, 2005), we suggest that a concentration of around 100 µg of imidacloprid per kg in pollen cakes may be a reasonable positive control. However a positive control is not necessary if a maximum level of exposure to the transgenic toxin is accurately measured.…”

Weight of evidence evaluation of a network of adverse outcome pathways linking activation of the nicotinic acetylcholine receptor in honey bees to colony death

“…In another study, upon exposure to 48 μg imidacloprid/L, honey bees demonstrated reduced food consumption and a significant decrease in foraging activity as measured by the number of trips to an artificial feeder (Ramirez-Romero et al, 2005). Bumble bees exposed for a prolonged period (28 d) to 10 μg imidacloprid/L in the diet exhibited significant impairment in their foraging performance compared with controls (Gill and Raine, 2014).…”

Applications (EFSA‐GMO‐RX‐MON810) for renewal of authorisation for the continued marketing of (1) existing food and food ingredients produced from genetically modified insect resistant maize MON810; (2) feed consisting of and/or containing maize MON810, including the use of seed for cultivation; and of (3) food and feed additives, and feed materials produced from maize MON810, all under Regulation (EC) No 1829/2003 from Monsanto

“…Reviewing available scientific data on potential adverse effects on honeybees of the Cry1Ab protein or Bt-pollen of maize gathered either under laboratory or semi-field conditions, Malone and Burgess (2009) concluded that none of the Bt-plants commercially available at the time of the publication have significant impacts on the health of honeybees. Other feeding studies performed in controlled conditions with honeybees being fed either with Bt-pollen or mixtures of honey or sugar syrup containing purified Cry1Ab protein have indicated no direct adverse effects on larvae and adult survival (Ramirez-Romero et al, 2005Rose et al, 2007). Based on a meta-analysis of 25 independent laboratory studies assessing direct effects on honeybee survival of Cry proteins from currently commercialised Bt-crops, Duan et al (2008) concluded that the assessed Cry proteins do not negatively affect the survival of either honeybee larvae or adults in laboratory settings.…”