Gardening Guides
Sand Wasps Keep True Bugs in Check and Help Pollinate Summer Flowers
Look for these solitary wasps nesting in sandy sites and foraging on flowers in July and August
A number of solitary predatory wasps prefer to nest in sandy sites. Bicyrtes spp. are very common in late summer, and females can often be observed excavating their nests as they fling the sand particles behind them, like a dog. These gentle solitary wasps hunt true bugs, including stink bugs, leaf-footed bugs and occasionally assassin bugs. Many of these bugs feed on plant juices and can be damaging to plants, and some of the bug prey are predatory. These sand wasps are beneficial and an important part of the intricate web of life, helping to keep true bug populations in balance. They are also common flower visitors in July and August, seeking out additional nourishment from nectar, so they can play a role in the pollination of flowers.
Like other solitary wasps, these aren’t aggressive and don’t defend their nests. You can get up close and watch their entertaining excavating behavior without risk of being stung. By leaving areas of bare soil in your garden, especially sandy soil, and providing some of their preferred forage plants, you may have these wasps visiting and nesting in your garden next season.
Like other solitary wasps, these aren’t aggressive and don’t defend their nests. You can get up close and watch their entertaining excavating behavior without risk of being stung. By leaving areas of bare soil in your garden, especially sandy soil, and providing some of their preferred forage plants, you may have these wasps visiting and nesting in your garden next season.
A female reopens her nest entrance in a sandy beach with her prey clutched beneath her.
How They Help
Sand wasps are predatory, solitary wasps. Females hunt true bugs, insects belonging to the insect families Pentatomidae (stink bugs), Coreidae (leaf-footed bugs) and, occasionally, Reduviidae (assassin bugs).
Besides hunting their prey, adults also visit a variety of flowering plants for nectar and can be considered pollinators in some cases. Like many other solitary wasps, these wasps often demonstrate a preference for plants with white flowers. Nectar from flowering plants provides energy for the adults, especially females when they are excavating nests and hunting for prey.
How They Help
Sand wasps are predatory, solitary wasps. Females hunt true bugs, insects belonging to the insect families Pentatomidae (stink bugs), Coreidae (leaf-footed bugs) and, occasionally, Reduviidae (assassin bugs).
Besides hunting their prey, adults also visit a variety of flowering plants for nectar and can be considered pollinators in some cases. Like many other solitary wasps, these wasps often demonstrate a preference for plants with white flowers. Nectar from flowering plants provides energy for the adults, especially females when they are excavating nests and hunting for prey.
How to Spot Sand Wasps
Adults: Sand wasps are very common in areas with sandy soil, their preferred nesting place. Adults are often hairless, or nearly so, and have a black head, thorax and abdomen. The abdomen has prominent stripes or markings, usually white or yellow (occasionally red in southern species), and is tapered, ending in a point. Sand wasps can have eyes that have a yellow-green, green or blue cast. These wasps are medium-size and average about 0.7 inch (18 millimeters) in length.
Babies (larvae): Larvae are cream-colored and legless and develop below ground, feeding on the bug prey provided by their mother.
Adults: Sand wasps are very common in areas with sandy soil, their preferred nesting place. Adults are often hairless, or nearly so, and have a black head, thorax and abdomen. The abdomen has prominent stripes or markings, usually white or yellow (occasionally red in southern species), and is tapered, ending in a point. Sand wasps can have eyes that have a yellow-green, green or blue cast. These wasps are medium-size and average about 0.7 inch (18 millimeters) in length.
Babies (larvae): Larvae are cream-colored and legless and develop below ground, feeding on the bug prey provided by their mother.
A sand wasp forages on Virginia mountain mint (Pycnanthemum virginianum).
How to Lure Them
Provide a nesting place. Besides a continuous succession of flowering plants, these wasps need a sandy site in the ground to excavate their nests.
Maintain a pesticide-free yard. Don’t use pesticides, especially insecticides, in the garden, particularly on flowering plants.
How to Lure Them
Provide a nesting place. Besides a continuous succession of flowering plants, these wasps need a sandy site in the ground to excavate their nests.
Maintain a pesticide-free yard. Don’t use pesticides, especially insecticides, in the garden, particularly on flowering plants.
Offer forage plants and nesting materials for adults. Nest initiation begins in mid-July. Once the wasps have found a suitable nesting site in sandy soil, they begin hunting for prey in the landscape.
Female sand wasps excavate the shallow nesting burrow in sand by digging in the soil, similar to a dog digging for a bone, in a frantic, fast-paced technique. Excavated sand particles are flung with the forelegs underneath and behind the wasp as they dig.
Once nest provisioning has occurred, male and female sand wasps can be observed visiting flowers for nectar in late July through early September.
Sample summer plant list for adults: Swamp milkweed (Asclepias incarnata), pale Indian plantain (Arnoglossum atriplicifolium), common boneset (Eupatorium perfoliatum), Virginia mountain mint (Pycnanthemum virginianum) and rattlesnake master (Eryngium yuccifolium)
Browse plants native to your region
Female sand wasps excavate the shallow nesting burrow in sand by digging in the soil, similar to a dog digging for a bone, in a frantic, fast-paced technique. Excavated sand particles are flung with the forelegs underneath and behind the wasp as they dig.
Once nest provisioning has occurred, male and female sand wasps can be observed visiting flowers for nectar in late July through early September.
Sample summer plant list for adults: Swamp milkweed (Asclepias incarnata), pale Indian plantain (Arnoglossum atriplicifolium), common boneset (Eupatorium perfoliatum), Virginia mountain mint (Pycnanthemum virginianum) and rattlesnake master (Eryngium yuccifolium)
Browse plants native to your region
A female enters a burrow with a bug clutched beneath her.
Life cycle. After emerging from their natal nest in early July, females mate with males and begin nest construction. Nests can be constructed in aggregations, especially in large, open sandy sites, but more often singly.
Females search and hunt for prey in vegetation, typically low to the ground. After stinging the prey to immobilize it, they return to their excavated sand burrow, clutching the paralyzed prey beneath them.
These sand wasps mass-provision their nest, caching multiple true bugs (three to 11) in one burrow, or enough food for a single wasp larva, then close the nest after an egg has been laid on one of the prey. The burrows can have a single brood chamber or more than one chamber (brood cell). A female will excavate multiple nest burrows in her lifetime.
The larvae hatch in the following days and consume the cached prey for the next four to seven days. When the food provisions are entirely consumed, each larva spins a cocoon and prepares to pupate.
Region by region: What to do in your garden this month
Life cycle. After emerging from their natal nest in early July, females mate with males and begin nest construction. Nests can be constructed in aggregations, especially in large, open sandy sites, but more often singly.
Females search and hunt for prey in vegetation, typically low to the ground. After stinging the prey to immobilize it, they return to their excavated sand burrow, clutching the paralyzed prey beneath them.
These sand wasps mass-provision their nest, caching multiple true bugs (three to 11) in one burrow, or enough food for a single wasp larva, then close the nest after an egg has been laid on one of the prey. The burrows can have a single brood chamber or more than one chamber (brood cell). A female will excavate multiple nest burrows in her lifetime.
The larvae hatch in the following days and consume the cached prey for the next four to seven days. When the food provisions are entirely consumed, each larva spins a cocoon and prepares to pupate.
Region by region: What to do in your garden this month
Family: Crabronidae
Genus: Bicyrtes
Common name: Sand wasps
Distribution: North and Central America, from southern Canada southward to Panama and the Caribbean Islands
Habitat: Open, sunny sites with sandy soil, including gardens, meadows, prairies, old fields and farms
When to look for them: In the northern United States, early July is often when the first sightings of adult wasps occur (earlier farther south); nest construction and provisioning begin in July. Following these initial tasks, adults can be observed visiting flowers in mid to late July through early September.