Stigmus americanus

Packard, 1867

aphid wasp

Stigmus americanus is a small aphid wasp in the Crabronidae (formerly ). It is native to North America and is known for nesting in twigs of various trees and shrubs. The provisions its nests with paralyzed aphids as food for its larvae, and is subject to by cuckoo wasps in the Omalus.

Pronunciation

How to pronounce Stigmus americanus: /ˈstɪɡməs əˌmɛrɪˈkeɪnəs/

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Habitat

Nests in twigs of trees and shrubs including Erythrina, Paeonia, Sambucus, Chionanthus, Syringa, Prunus, Polyphorus, and Sassafras. Frequently utilizes pre-existing cavities but also excavates its own nests.

Distribution

North America; recorded from Canada (Alberta) and the United States.

Diet

provision nests with paralyzed aphids. Larvae feed on the paralyzed aphids provided by the mother.

Host Associations

Aphids - preyParalyzed and used to provision nests for larval development
Erythrina - nest siteTwigs used for nesting
Paeonia - nest siteTwigs used for nesting
Sambucus - nest siteTwigs used for nesting
Chionanthus - nest siteTwigs used for nesting
Syringa - nest siteTwigs used for nesting
Prunus - nest siteTwigs used for nesting
Polyphorus - nest siteTwigs used for nesting
Sassafras - nest siteTwigs used for nesting
Omalus iridescens - Cuckoo wasp that parasitizes nests by laying in live aphids at hunting sites
Omalus purpuratus - Cuckoo wasp that parasitizes nests by laying in live aphids at hunting sites

Life Cycle

Females provision nests with paralyzed aphids and deposit on the thoracic venter and of the aphids. Larvae hatch and feed on the paralyzed aphids, eventually emerging as from the shells.

Behavior

Nests in twigs, frequently utilizing pre-existing cavities but capable of excavating its own nests. Females paralyze aphids and transport them to nests.

Ecological Role

of aphids; may contribute to control. Serves as for parasitic cuckoo wasps.

Similar Taxa

Other PemphredoninaeSimilar nesting in twigs and provisioning, but specific plant associations and geographic range may differ

More Details

Parasitism

The cuckoo wasps Omalus iridescens and Omalus purpuratus are known of Stigmus americanus. These parasites lay in live aphids at the hunting sites of S. americanus; the then paralyzes the aphids and transports them to its nest along with the embedded parasite eggs.