The curved pebble bee is our pollinator of the month for August 2026. When I first learned about this curious bee, I was amazed by how it builds its nests. I observed pebble bees on my cup plant (Silphium perfoliatum) in my meadow garden.

Fascinated by any type of new bee in my garden, I photographed the curved pebble bee (Dianthidium curvatum) extensively. Unlike some of my colleagues who study insects and bees, I have yet to try slowing them down with an ice cube for better photos.

Range and Habitat

The curved pebble bee is primarily at home in Texas, Colorado, the desert of Idaho and Utah, and in the Gulf States. But there are some records of it in Kansas, Nebraska, and South Dakota as well.

Pebble bees, as a Genus, congregate mainly along the Rocky Mountains, West Coast, and Gulf of America states. But there are scattered records of these bees throughout the United States. 

They are members of Leafcutter, Mason, and Resin bees in the Family Megachilidae. There are some 20 described species. 

Habitat

Though there range includes mountains and coastlines, pebble bees make their homes in open areas such as prairies, steppe, dry shrublands, and gardens. Arid areas, such as deserts and savannah are also home to these bees.

Nesting and Life Cycle

The curved pebble bee and other types of pebble bees make a very unique nest structure. Using plant resin, leaf matter, and small pebbles or sand pebbles, they form a nest in a branch crotch or on plant stems. This nest appears like a stone hut, with the entrance hole at the bottom to keep the brood dry from rain. Another of God's amazing creatures on display.

The pebble bee is a solitary bee who has a four-stage life cycle (egg, larva, pupa, adult). With several cells in the nest, a female bee lays a single egg per cell, providing each with a supply of pollen and nectar. Then the cell is closed.

After hatching, the larva eats the stored pollen and nectar, then spins a cocoon to enter the pupa stage. Most species of pebble bees overwinter fully as a developed pupae, or adult, and emerge from the nest in spring, where they begin the process over again, after mating. 

Pollination

While many other bees are generalists (feeding and foraging on a variety of plant flowers), the curved pebble bee is a specialist of the Asteraceae Family. Its primary food source are the flowers of Sunflowers (Helianthus), Sneezeweed (Helenium), Gumweed (Grindelia), Coreopsis, and Silphium. All their pollen collection is on these plants. This is why I see them in my gardens, I have a lot of both gumweed and silphiums. 

Plantings to Add

If you are wanting to possibly see pebble bees in your own gardens, then there are two things you need. One is open ground with gravel or sand for them to use for nestbuilding. Another is plants. Add any of the following plants to your garden to attract these bees in.

• Curlycup gumweed
• Cup plant
• Rosinweed
• Common sneezeweed
• Purple-headed sneezeweed
• Compass plant
• Prairie dock
• Bigflower coreopsis
• Plains coreopsis
• Tall coreopsis
• Common sunflower
• Maximilian sunflower
• Willowleaf sunflower
• Stiff sunflower
• Ashy sunflower
• Tuberous sunflower

Conclusion

The curved pebble bee is not one of our more common pollinators, but they can be important specialists of our sunflowers and other members of the Aster Family. They are unique and can be fun to watch. I hope you get the chance to see them.

Happy planting!