Native Sweat Bees are Flower Loyal Pollinators
One bee species thrives in urban environments and human-modified areas like cities, farms and agricultural lands, and is widespread throughout North and South America. According to entomologists at UC Riverside, this suggests that this species of native sweat bee is potentially a promising pollinator.
The European honeybee, which is a famous cousin of the sweat bee, is rented out to farmers for pollination purposes and this can be very expensive. The honeybee is also faced with many hazards from pesticides to climate change. The sweat bee may become a supplemental pollinator.
Sweat bees are less well known than European honeybees, but they labor alongside them oftentimes and deserve credit as pollinators, as do bumblebees and other native bees. They are commonly found in urban, natural and agricultural places in North America, and pollinate both cultivated crop-type plants and wildflowers.
This fascinating 3:11-minute video by Andreas Kay shows a sweat bee from the Amazon region of Ecuador grooming and licking honey. This species is Augochloropsis sp. Halictidae and part of the larger family of sweat bees.
The in-depth foraging behavior of one particular species of sweat bee, Halictus ligatus, was recently studied by Ph.D. candidate Jacob Cecala, and Erin Wilson Rankin, an associate professor of entomology. Their paper was published in the journal Ecology. This small, common and often-overlooked species is classified as a “generalist” which means it is known to feed on many different flowers. It was not known whether these bees were flexible in their flower selection and whether an individual bee’s floral choices might change from day-to-day.
Cecala captured sweat bees that fed on flowers in multiple commercial plant nurseries across Southern California to study their daily routine. He marked each bee with dots of different colored non-toxic paint to see which plants a bee visited.
The next day Cecala returned and caught about 52% of the marked bees again. He repeated the experiment four times during the summer and four times in autumn. Each time he recaptured about 50% of them. Virtually all of them at 96% were found on the same plant species as on the first day. The findings of this study suggest that most individual bees make common and consistent choices about what they eat, and that they forage and feed on the same plant species every day.
These are promising results, according to Cecala, since plant nurseries are artificial habitats constructed by humans. It implies such environments are not devoid of biodiversity and that these native bees fly around visiting plants that provide them with pollen and nectar sources.
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