Rittschofetal_AEE2023DataFiles

Data corresponding to manuscript: Lack of adequate floral resources is a key driver of bee population declines and honey bee colony loss, particularly in agricultural landscapes. Most studies evaluating floral resource use and land management consequences in honey bees focus on the period after new colony founding from reproductive swarms (spring-fall). Few studies have investigated nutrition in the late-winter/early-spring (LWES) period, the critical time when colonies break their winter dormancy and increase their colony populations in preparation for swarming. Growth during this timeframe influences beekeepers’ ability to produce new colonies and predicts colony productivity for the remainder of the active season. In agricultural areas growing summer annual crops, many fields are fallow during LWES and anecdotally grow large quantities of early blooming winter annual herbaceous “weeds”. The relative value of these resources to honey bee colony health is unknown. In this study, conducted in central Kentucky, we characterized winter annual abundance across different land cover types. We placed colonies on sites with varying quantities of near-colony blooming winter annual plants and assessed changes in colony growth and individual worker immune system function over LWES. We found that winter annual plants are most abundant on croplands and limited on forested sites and sites dominated by grasses (including lawns and pastures). Colonies on sites with the lowest quantities of winter annual plants showed reduced LWES growth and patterns of individual worker gene expression consistent with nutritional stress. We used the National Landcover Database to show that proximity to crop fields at larger spatial scales also had positive impacts on colony growth during LWES. Taken together, these results suggest winter annual plants, and, more generally, croplands, may provide critical floral resources for honey bees during the critical pre-swarm growth period following winter dormancy.