Great Black Wasp

Sphex pensylvanicus

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Photo of a great black wasp on a bindweed flower
A strikingly large black wasp with smoky black wings that shine with blue iridescence, the great black wasp is often seen busily eating nectar and pollen from flowers in summertime.
Family

Sphecidae (thread-waisted wasps) in the order Hymenoptera (ants, bees, wasps)

Description

The great black wasp is a strikingly large, black wasp with smoky black wings that shine with blue iridescence. It is a type of digger wasp, and most people see it busily eating nectar and pollen from flowers in summertime.

The body is satiny matte black. There is a narrow constriction between thorax and abdomen (it is a “thread-waisted” wasp). The wings are shiny, smoky black, with blue iridescence, usually folded together lengthwise down the back. The legs are long and spiny. The mandibles (mouthparts), usually held together and overlapping, are relatively large and sickle-shaped, with an extra prong in the middle of each curve.

Size

Length: from about 1 to nearly 1½ inches (females larger than males)

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Photo of a great black wasp on a bindweed flower
Great Black Wasp
The great black wasp, though intimidating, is a solitary wasp and is not at all aggressive to people.
Habitat and conservation

Great black wasps are most often seen visiting flowers in open areas, July through September.

As with other native wasps, only females have a stinger, and they use it for immobilizing prey to feed their young. They have no group hive to defend, and they do not sting people maliciously — only if they are mistreated. The sting is reportedly painful but harmless, except to individuals with special allergies to the stings. Please don’t kill these wasps out of fear.

Foods

Insects with different life stages usually eat different foods during those stages. As an immature, grublike larva, this wasp eats paralyzed katydids and grasshoppers that the mother wasp had stung and buried with her eggs, to serve as a larder for her young. Once the wasps pupate and become mature adults with wings, they eat nectar and pollen from flowers to sustain themselves through their final, reproductive, tasks.

image of Great Black Wasp Distribution Map
Distribution in Missouri

Statewide.

Life cycle

Like other wasps, this species undergoes complete metamorphosis through egg, larva, pupa, and adult. But this is a solitary wasp. It does not live in colonies. After mating, the female digs a hole in the ground, captures a katydid or grasshopper, drags it into the hole with her strong mandibles, and lays a single egg on it. Then she adds two more hoppers to the larder. She digs new chambers for her next eggs. Upon hatching, the larvae eat the three insects provisioned for them, then pupate and emerge as adults.

Human connections

A friend to gardeners: a single female great black wasp can capture 16 hoppers a day, helping control grasshoppers, which chew on crops and garden plants.

This wasp also pollinates plants in the milkweed, carrot, and bean families.

With their impressive size and shiny blue-black wings, these wasps are fun to watch. Many famous naturalists have written entertaining, fascinating accounts of this and other digger wasps; those of Howard Ensign Evans (“Wasp Farm”) and J. Henri Fabre are highly recommended.

Ecosystem connections

Great black wasps help control grasshopper and katydid populations.

They pollinate many plants, including the fascinating rattlesnake master of the tallgrass prairie.

Catbirds and sparrows have been documented stealing and eating grasshoppers that had been caught by female great black wasps.

This wasp, in the genus Sphex, is a member of the family Sphecidae (SFEE-ci-dee), the thread-waisted wasps or digger wasps, which are all solitary. Relatives include mud daubers and the very closely related great golden digger wasp (S. ichneumoneus). Solitary wasps do not have the aggressive defensive behaviors of yellowjackets and other wasps that nest in colonies.