Agroecological measures in meadows promote honey bee colony development and winter survival

Abstract

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.

Effective pest management approaches can mitigate honey bee (Apis mellifera) colony winter loss across a range of weather conditions in small-scale, stationary apiaries

“…Indeed, DeGrandi-Hoffman et al (2020) found that survival of fed colonies was higher than unfed colonies, despite fed colonies having higher Varroa populations and deformed wing virus levels. Furthermore, Hernandez et al (2023) demonstrated that increased forage quality led to higher populations of honey bees and consequently higher resistance in the population against Varroa . Future work should investigate these links, particularly the influence of landscape quality and supplemental feed on the ability of a colony to withstand Varroa .…”

“…Both Varroa infestation and lack of forage in the spring and summer reduce population size and small colonies struggle to thermoregulate and have lower overwintering success ( Owens 1971 ). Furthermore, poor nutrition disturbs honey bee colonies’ ability to withstand Varroa infestations; several studies describe a connection between protein supplemented diets, Varroa levels, and deformed wing virus (a virus vectored by Varroa mites) ( Janmaat and Winston 2000 , DeGrandi-Hoffman et al 2010 ) as well as between landscape quality and Varroa parasitization ( Dolezal et al 2019 , Hernandez et al 2023 ).…”