Impact of soybean on wild and managed bee health within a landscape context

Although soybean is domesticated for self-pollination, increasing evidence suggests pollination by honey bees (Hymenoptera: Apidae, Apis mellifera) and wild bees can increase soybean yield. While soybean pollen and nectar are collected by bees, it is not clear how bees use soybeans as forage, how soybean pollen consumption affects health, or how either of these factors are affected by the surrounding landscape diversity. During 2015 we started an on-farm study to better understand the dynamics between pollinators and soybeans in areas of high and low landscape diversity. Our goal is to determine the value of pollination to soybeans and if the pollinator community benefits from soybean as a source of pollen and nectar. We identified 18 commercial soybean fields surrounded by either a simple (low diversity, n = 10) or complex (higher diversity, n =8) landscape in central Iowa. On a subset of each landscape type (n=5), we placed four honey bee hives adjacent to soybean fields. Pollen traps were used to determine the use of soybean pollen by honey bee during soybean bloom. Individual bees taken from soybean fields and from honey bee colonies before, during, and after soybean bloom were used to measure health. In addition, the abundance and diversity of native bee’s and their health were measured at all sites. Finally, the impact of pollination on soybean yield was estimated at all locations, including those not receiving honey bee hives.