Gardening Guides
Keep an Eye Out for Fast-Moving Calliopsis Bees
These small native bees can often be seen foraging on vervain in the summer
Calliopsis, a small genus of bees, belong to the same family as mining bees (Andrena spp.) but are less common. Adult Calliopsis are fast flyers and can be found active as adults July through August. Males often chase or search for females near large patches of their favorite flowers, including vervain (Verbena spp.). There are two specialists in this bee genus that occur in the eastern United States; you can attract them by planting the perennials that the females rely upon for collecting pollen for their offspring.
Calliopsis nest in the ground; each female builds her own solitary nests. When an ideal site is located, it is not uncommon for several female bees to build their nests in close proximity in groups or aggregations.
Calliopsis nest in the ground; each female builds her own solitary nests. When an ideal site is located, it is not uncommon for several female bees to build their nests in close proximity in groups or aggregations.
A male Calliopsis andreniformis visits hoary vervain (Verbena stricta).
When to look for them: Summer is the optimum time to observe Calliopsis. The three species that occur in the eastern U.S. and southern Canada are active from mid-to-late June through August.
Two of the three species are specialists: The females seek out pollen from a narrow range of plants from one to a few plant genera. C. nebraskensis is a specialist of vervain (Verbena spp.), and C. coloradensis is a specialist of goldenrod (Solidago spp.) and beggarticks (Bidens spp.).
When to look for them: Summer is the optimum time to observe Calliopsis. The three species that occur in the eastern U.S. and southern Canada are active from mid-to-late June through August.
Two of the three species are specialists: The females seek out pollen from a narrow range of plants from one to a few plant genera. C. nebraskensis is a specialist of vervain (Verbena spp.), and C. coloradensis is a specialist of goldenrod (Solidago spp.) and beggarticks (Bidens spp.).
A male and female Calliopsis nebraskensisis mate on the flowers of hoary vervain.
How They Help
Calliopsis have a limited number of plants that they visit; they are not broad, generalist foragers. For the plants that they specialize on, like vervain, they are one of the primary pollinators of that plant because they are among the few bees that actively collect pollen from the flowers and move the pollen from flower to flower. Female C. nebraskensisis, the specialist of vervain, have special combs on their forelegs to extract pollen from vervain flowers.
How They Help
Calliopsis have a limited number of plants that they visit; they are not broad, generalist foragers. For the plants that they specialize on, like vervain, they are one of the primary pollinators of that plant because they are among the few bees that actively collect pollen from the flowers and move the pollen from flower to flower. Female C. nebraskensisis, the specialist of vervain, have special combs on their forelegs to extract pollen from vervain flowers.
A male Calliopsis nebraskensis perches on a flower and waits for a female.
How to Spot Calliopsis Bees
Adults. Calliopsis vary in length; the small species measure just over one-tenth of an inch (4 millimeters), and the larger Calliopsis are about four-tenths of an inch (10 millimeters). C. andreniformis, the most commonly observed species, are dark gray or black with a narrow form. Males have a bright yellow face and legs, and pale abdominal stripes. Female C. andreniformis have three prominent oblong white markings on the face. Calliopsis often have light-colored blue or green eyes.
Babies (larvae). Larvae are grub-like and pale yellow to cream in color. You’re unlikely to see larvae since all Calliopsis nest in the ground.
How to Spot Calliopsis Bees
Adults. Calliopsis vary in length; the small species measure just over one-tenth of an inch (4 millimeters), and the larger Calliopsis are about four-tenths of an inch (10 millimeters). C. andreniformis, the most commonly observed species, are dark gray or black with a narrow form. Males have a bright yellow face and legs, and pale abdominal stripes. Female C. andreniformis have three prominent oblong white markings on the face. Calliopsis often have light-colored blue or green eyes.
Babies (larvae). Larvae are grub-like and pale yellow to cream in color. You’re unlikely to see larvae since all Calliopsis nest in the ground.
A female Calliopsis andreniformis (note the three oblong white markings on the face)
How to Lure Them
Provide a nesting place. Besides providing a pesticide-free garden and continuous succession of flowering plants, you will need to provide a place where Calliopsis can nest. All Calliopsis nest in the ground. C. andreniformis nests have been found in large aggregations in compacted, well-drained soil.
Maintain a bee-safe yard. Do not use pesticides, especially insecticides, in the garden, particularly on flowering plants or lawn, where many mining bees prefer to build nests.
Forage plants for adults. Calliopsis can reliably be found foraging on vervain, including blue vervain (Verbena hastata) and hoary vervain (V. stricta).
How to Lure Them
Provide a nesting place. Besides providing a pesticide-free garden and continuous succession of flowering plants, you will need to provide a place where Calliopsis can nest. All Calliopsis nest in the ground. C. andreniformis nests have been found in large aggregations in compacted, well-drained soil.
Maintain a bee-safe yard. Do not use pesticides, especially insecticides, in the garden, particularly on flowering plants or lawn, where many mining bees prefer to build nests.
Forage plants for adults. Calliopsis can reliably be found foraging on vervain, including blue vervain (Verbena hastata) and hoary vervain (V. stricta).
A female Calliopsis nebraskensis, a pollen-collecting specialist of vervain, forages on hoary vervain.
Life cycle. In the upper Midwest, Great Lakes and Northeast regions, Calliopsis species usually have one generation per year. Female Calliopsis emerge from their nest in the ground as adults in late June or early July, mate with males near the nest or on flowers, then look for a site to begin construction of the nest. Nests are solitary and can occur in groups (aggregations). Nests are excavated by the female; she uses her forelegs to dig a main burrow shaft, and her abdomen and legs push the soil upward out of the excavated hole. From the long, central shaft, short or long lateral shafts are created from which small oval to round cells for larvae (called brood cells) are excavated. The nest architecture can vary from species to species.
Females forage in the landscape, and collect pollen and nectar from flowers. These floral resources are combined to form a pollen ball (bee bread) when the female returns to the nest. When enough pollen and nectar have been collected for a given brood cell, the female lays an egg on the provisions and then caps the cell with soil. The capped brood cell is backfilled with soil, often using soil excavated for the next brood cell in the nest. The larvae consume the pollen and nectar provisions, then overwinter in a prepupal stage. The following spring, they continue their development into pupae and emerge as adults in late June.
Region by region: What to do in your garden this month
Life cycle. In the upper Midwest, Great Lakes and Northeast regions, Calliopsis species usually have one generation per year. Female Calliopsis emerge from their nest in the ground as adults in late June or early July, mate with males near the nest or on flowers, then look for a site to begin construction of the nest. Nests are solitary and can occur in groups (aggregations). Nests are excavated by the female; she uses her forelegs to dig a main burrow shaft, and her abdomen and legs push the soil upward out of the excavated hole. From the long, central shaft, short or long lateral shafts are created from which small oval to round cells for larvae (called brood cells) are excavated. The nest architecture can vary from species to species.
Females forage in the landscape, and collect pollen and nectar from flowers. These floral resources are combined to form a pollen ball (bee bread) when the female returns to the nest. When enough pollen and nectar have been collected for a given brood cell, the female lays an egg on the provisions and then caps the cell with soil. The capped brood cell is backfilled with soil, often using soil excavated for the next brood cell in the nest. The larvae consume the pollen and nectar provisions, then overwinter in a prepupal stage. The following spring, they continue their development into pupae and emerge as adults in late June.
Region by region: What to do in your garden this month
Family: Andrenidae
Subfamily: Panurginae
Genus: Calliopsis
Numbers: About six subgenera and 68 species in North America (north of Mexico); three species east of the Mississippi and 86 species worldwide
Distribution: The Western Hemisphere from southern Canada southward to Argentina and Chile
Habitat: Open, sandy sites, woodland edges, prairies and old fields