The effect of the size of the bumblebee (Bombus terrestris L.) on the susceptibility to the pesticide dimethoate 40 percent

摘要

In relation to the adaptation to the effect of the size of the body on the susceptibility to bumblebees to pesticides, tests were done in order to define " bumblebees of average size". In these tests the effect of the size of the bumblebee, expressedin (1) width of the thorax, (2) weight and (3) age on the susceptibility for Dimethoate 40 percent, was determined. The data confirm previous results that the size of the bumblebee indeed has an effect on the susceptibility of bumblebees to Dimethoate 40 percent. Considering the action of pesticides, it is assumable that the relation between size and susceptibility is valid for most pesticides. There is a statistically significant correlation between the width of the thorax and the weight. The weight is a valid and practical criterion for selection. Relatively small and relatively big bumblebees show a significant distinct susceptibility. An indication for modal bumblebees, based on the weight is the criterion: 0.1400 g - 0.2300 g.