Distinct pollinator communities persist among co-flowering specialty crops in Indiana

By Stroh et al.

Specialty crops, which include a variety of non-staple fruits and vegetables, are pollinated by a diverse array of bees. Different geographic regions harbor unique bee communities, although non-native Western honey bees (Apis mellifera) are used to supplement the pollination provided by wild, native bees in some specialty crops. There are a variety of other factors that affect bee community composition for individual crops, including crop bloom phenology and flower morphology. Crops that bloom in the spring are exposed to a different suite of early-season bees than those that bloom in the summer months. Flower shape, which determines ease of access for different bee species, further filters bee communities in individual cropping systems.

We sampled bee communities using pan traps and flower observations on commercial apple (Malus domestica), blueberry (Vaccinium corymbosum), tomato (Solanum lycopersicum), and watermelon (Citrullus lanatus) farms in Indiana, a state dominated by agronomic crop production with small pockets of specialty crops. Apples, blueberries, and watermelons were stocked with honey bees, while tomatoes were not.

We found that distinct bee communities persisted in co-blooming apples and blueberries, as well as tomatoes and watermelons. While flower visits in spring-blooming apples and blueberries were dominated by honey bees (70% of visits), a diverse array of wild bees were also present, including spring-flying mining bees (Andrena) in both crops. In the summer-blooming crops, we found that bumble bees (Bombus) provided the majority of flower visits (62% of visits) in tomatoes. Despite stocking with honey bees, watermelon flower visits were dominated by sweat bees (Lasioglossum) (65% of visits). Our results indicate that diverse wild bee communities are found among specialty crops in the Midwest, and wild bees are particularly large contributors to tomato and watermelon pollination.

 Read the scientific publication in JPE