Commercial strawberry production relies heavily on insect activity, making the relationship between the plant and its pollinators a fundamental aspect of farming. Although strawberry flowers can self-pollinate, the quality and quantity of the final fruit are significantly improved by foraging insects. Bees are integral partners whose pollination services directly translate into marketable berries. Without effective bee pollination, a large portion of the harvest would be unmarketable.
The Floral Characteristics That Attract Bees
The strawberry flower presents a simple, disc-shaped structure with exposed anthers and approachable nectar, which makes it an appealing target for a wide variety of pollinating insects. Its five white petals provide a visible landing platform, and its radial symmetry offers easy access to the reproductive parts. This generalized floral design ensures visitation by numerous species beyond just the honeybee.
The primary rewards for bees are nectar and pollen, which serve as carbohydrate and protein sources, respectively. Nectar is produced at the base of the stamens and provides the energy for foraging. Pollen is a source of protein and fat necessary for larval development in the hive.
Although strawberry flowers are self-fertile, the stigmas are often receptive before the anthers release their pollen. This difference in timing encourages cross-pollination from a neighboring plant, which results in larger and better-quality fruit. The flower’s modest reward system requires between six and fifteen bee visits per flower to ensure full pollination.
How Pollination Determines Strawberry Fruit Quality
The strawberry is classified as an aggregate fruit, meaning the edible flesh develops from the enlarged receptacle of the flower. The tiny “seeds” on the outside of the berry are achenes, and each one must be fertilized for the tissue beneath it to swell. To achieve a desirable fruit shape, 70 to 80 percent of the achenes must be successfully fertilized.
If the flower receives inadequate or uneven pollen, the result is a misshapen, small berry often referred to as a “nubbin”. These malformed fruits occur in the areas where the achenes were not fertilized, causing depressions or cavities in the fruit surface. Proper bee pollination ensures that pollen is distributed homogeneously across the many stigmas of the flower’s receptacle, leading to a fully developed, evenly shaped fruit.
Successful pollination affects shape and size, and also increases the fruit’s quality. Open-pollinated strawberries exhibit higher sugar content, greater fresh weight, and a more intense red color. They also demonstrate a better shelf life, sometimes lasting seven days in storage compared to four days for self-pollinated fruit.
Supporting Diverse Bee Populations for Peak Yield
Growers often rely on managed honeybees for pollination, but a diverse assemblage of native bee species is superior for maximizing yield. Wild bees, such as solitary bees and bumblebees, are more effective pollinators than honeybees. This difference is due to the varied foraging behavior of native species, which crawl deeper into the flower and distribute pollen more thoroughly across the receptacle.
To ensure a healthy and effective pollinator community, farmers and gardeners can implement several practical strategies.
- Provide nesting habitats, such as leaving ground undisturbed for ground-nesting bees or installing bee hotels.
- Stagger the planting of different strawberry cultivars to extend the flowering period and provide a continuous food source.
- Carefully manage broad-spectrum pesticides, as chemicals applied during flowering harm foraging insects.
- Utilize integrated pest management and choose drip irrigation, since overhead watering washes away nectar and pollen rewards.
By focusing on a diverse pollinator community and providing a healthy environment, growers can harness the full potential of this natural partnership.