Methods for the evaluation and comparison of the structure of numerous honeybee colonies are needed for the development of applied and fundamental field research, as well as to evaluate how the structure and activity of honeybee colonies evolve over time. ColEval complements existing methods, as it uses an online reference image bank for (human) learning and training purposes. ColEval is based on the evaluation of the surface area percentage occupied by different components of a honeybee colony: adult worker bees, open and capped brood, honey, nectar, and pollen. This method is an essential tool for the description of the evolution in the size of honeybee colonies. The procedure makes allowances for tendencies between different observers and uses them to calculate accurate measurements of honeybee colony evaluation. ColEval thus allows for a posteriori comparison of under- or over-evaluation made by different observers working on the same project; it is thus possible to eliminate observer bias in the measurements and to conduct large surveys.

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Cinquante deux souches de B. thuringiensis appartenant ~ 13 s6rovars ont 6t6 test6es sur des chenilles n~onates de Spodoptera frugiperda en contaminant la surface du milieu semi-synth6tique d'~levage. Deux souches du s6rovar kenyae et une autre du s~rovar tolworthi provoquent ie plus de mortalitY, suivies par les souches des s~rovars aizawai et kurstaki. Les souches les moins actives appartiennent aux s~rotypes alesti, dendrolimus, sotto et colmeri. L'action des souches sur le d6veloppement larvaire a aussi 6t~ abord6e. Les souches des s6rovars kenyae, aizawai et kurstaki ont ralenti le d6veloppement des chenilles, tandis que les souches des s6rovars alesti, sotto et colmeri n'ont eu aucun effet.

The homogenization of agricultural landscapes has led to a decrease in pollinator diversity and abundance. In response to this decline, farmers have implemented agroecological measures, which, in meadows, aim at providing more floral resources. These measures are the availability of unmown floral strips, delayed mowing, and discouraging the use of the conditioner, a device known to harm insects. The aim of our study was to investigate the cascade of effects of these agroecological measures on honey bee colony development and winter survival. We (1) determined the effect of these measures on colony size during the nectar and pollen collecting season in spring and summer, (2) evaluated the effect of spring and summer colony sizes on autumn size, and (3) described the effect of colony size in autumn on winter mortality. In this study, 300 honey bee colonies were monitored over three years in three cantons of Switzerland. Colony size was defined by the numbers of brood cells and of adult workers. Honey bee colony size in summer and autumn was improved by agroecological measures on meadows and likely contributed to the increased overwintering success. This study is a first step toward the targeted identification of viable agroecological measures on temporary meadows that can be implemented to promote honey bee colonies health in the agricultural landscape.