Free Access
Volume 36, Number 4, October-December 2005
Page(s) 601 - 611
Published online 15 November 2005
Apidologie 36 (2005) 601-611
DOI: 10.1051/apido:2005039

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

Ricardo Ramirez-Romeroa, b, Josette Chaufauxc and Minh-Hà Pham-Delèguea

a   INRA, Laboratoire de Neurobiologie Comparée des Invertébrés, BP 23, 91440 Bures-sur-Yvette, France
b   Present address: Instituto de Ecologia, A.C., Km 2.5 Carretera Antigua a Coatepec No. 351, El Haya, 91070 Xalapa Veracruz, Mexico
c   INRA, Unité Génétique Microbienne et Environnement, La Minière, 78285 Guyancourt Cedex, France

(Received 19 July 2004 - revised 19 December 2004 - accepted 7 April 2005; Published online: 15 November 2005)

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.

Key words: Apis mellifera / Cry1Ab protoxin / insecticide / behaviour / risk assessment

Corresponding author: Ricardo Ramirez-Romero

© INRA, DIB-AGIB, EDP Sciences 2005