Attraction of Varroa jacobsoni, parasite of Apis mellifera by electrical charges
M.E. Colin1, D. Richard2, V. Fourcassie2 and L.P. Belzunces1
1Institut National de la Recherche Agronomique, Centre National d'Etudes Vétérinaires et Alimentaires, Centre de Recherches Agronomiques d'Avignon, Station de Zoologie-Apidologie, 84143 Montfavet Cedex, France
2Laboratoire de Neurobiologie de l'Insecte, Université Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse Cedex, France
Received 23 May 1991;
revised 9 September 1991.
Available online 30 September 2003.
Precise measurement of the electrical charges carried by honey bee workers allows one to investigate the role of this abiotic factor in bee contamination by the ectoparasitic mite Varroa jacobsoni. A metallic cylinder charged with four different intensities (chosen in the range measured on living bees) of either positive or negative sign was used as a lure. The mite's movements in the vicinity of the cylinder was videotaped and subsequently digitized. Spatial and temporal dimensions of the paths were computed by a specially designed analysis programme. The frequency and nature of the contacts with the lure were also noted.
A two-way ANOVA indicated no significant differences in the characteristics of the paths between charges of different intensities. However, the charge sign was found to influence the following characteristics: immobility, velocity, turning angle standard deviation and sinuosity. In addition, the frequency with which the mite contacted and climbed on the cylinder was higher in the case of negative charge. We suggest that the mites are not merely passively attracted towards the lure by the action of electrical forces. Rather, the detection of charges triggers a change in the movements of the animal which increases the probability to contact its host.
Keywords: Electrical charges; host finding; trajectometry; Varroa jacobsoni; Apis mellifera