Long before ripe blueberries reach grocery store shelves or end up in muffins, native bees play a critical role in their development. A recent University of Georgia study sheds light on how these wild pollinators are essential for one of the state’s most valuable crops.

Sarah Rezende, a Ph.D. candidate working with Associate Professor Jason Schmidt in the Department of Entomology, is researching what wild bees in Georgia need to thrive and how their activity impacts blueberry farm productivity.

As part of a USDA-funded project to improve blueberry yields through planting pollinator-friendly flowering plants, Rezende studied how wild bee populations vary across space and time in southeastern Georgia blueberry farms.

Blueberry industry’s impact

In 2023, Georgia’s blueberry industry was worth over $526 million, making it the eighth most valuable crop in the state and third nationally. This highlights the importance of healthy pollinator populations for the industry’s success.

Over two growing seasons, Rezende and her team surveyed eight farms by sampling bee activity within fields, along edges, and in neighboring forests. Their findings could help farmers better support native pollinators.

The study, published in Environmental Entomology, recorded over 5,000 wild bees across 72 species and 26 genera, Georgia’s most comprehensive survey of blueberry farm pollinators.

“I’m amazed by the bee diversity,” Rezende said. “There are tiny bees, larger bees, and small blue carpenter bees that nest in plant stems, an uncommon species abundant in this study.”

Bee activity fluctuated throughout the season, peaking after the blueberry bloom. This indicates native bees need resources beyond the three-week blooming period, as their populations require year-round support.

Bee abundance was highest at field edges between May and June, while forested areas maintained steady populations throughout the period. Species composition also changed over time and location, with different dominant species emerging at various times.

“This data is critical,” Rezende explained. “It shows which bees are active, when they’re active, and their habitat preferences, information vital for developing conservation strategies.”

Why blueberries depend on buzz pollination

While many growers use honeybees for pollination, they are less effective at a process called sonication, or buzz pollination, which blueberries specifically require. This technique involves bees vibrating their flight muscles to shake pollen loose from the anthers of flowers.

Native bees like the southeastern blueberry bee (Habropoda laboriosa) excel at this. A single female can pollinate up to 50,000 flowers and produce over 6,000 blueberries in a season. This is far more efficient than honeybees, which need six visits to pollinate the same number of flowers.

Georgia hosts over 500 native bee species, part of the 4,000 in the U.S. and 20,000 worldwide, but their pollination role is often overlooked.

Most native bees are solitary, not social like honeybees. They do not live in hives or produce honey but focus solely on pollination and reproduction. They nest in ground tunnels, wood, or leaf litter, utilizing various habitats.

Creating a habitat that provides continuous floral resources and diverse nesting sites can enhance native bee populations. This is especially important for species like blueberry bees, which nest underground and have a brief active period of about three weeks. If their emergence doesn’t match the blueberry bloom, they may lack food, reducing their numbers for the next season.

Native bees, such as the southeastern blueberry bee, emerge, breed, and provision their nests quickly. The female gathers pollen, lays eggs, and seals each nest cell, all within a short active period. After their brief season, they die, and the next generation emerges the following year.

The availability of nearby food determines how many eggs a female can produce, closer resources allow her to invest more in her offspring. A female can lay up to 20 eggs in her lifetime, directly affecting pollination success and blueberry yields.

Supporting native wild bees through habitat management and year-round floral resources is crucial for sustainable blueberry production. These pollinators not only improve crop yields but also preserve the rich biodiversity vital for ecological health.

Related articles:

Wild bees help blueberry fields flourish