Pemphredon inornata

Say, 1824

aphid wasp

Pemphredon inornata is a small solitary in the Crabronidae, commonly known as an wasp. The hunts aphids as for its , paralyzing them and transporting them to nest cavities in hollow stems, twig pith, or pre-existing holes in wood. It is one of approximately 20 recognized Pemphredon species in North America north of Mexico. The wasp has been documented exhibiting rapid, evasive that allows it to bypass guards at aphid colonies.

SaundersHymenopteraAculeataPlate13 by Edward Saunders. Used under a Public domain license.

Pronunciation

How to pronounce Pemphredon inornata: //pɛmˈfrɛdən ɪnɔrˈneɪtə//

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Identification

Small, predominantly black typically under 10 mm in length. Body form resembles a miniature thread-waisted wasp with short connecting to . is distinctly cubical (square-shaped) in outline. clear. straight. Lacks the color patterns seen in many other small wasps. Rapid, darting pattern distinguishes it from more hovering wasps at colonies.

Images

Habitat

Found in association with colonies on trees, shrubs, and herbaceous plants. Nests in pre-existing cavities including hollow stems, pith of broken twigs or berry canes, and holes in wood. Thorny stems may be preferred as nest sites due to reduced vertebrate .

Distribution

North America; Europe and Northern Asia (excluding China); Southern Asia. GBIF records confirm presence in North America and Europe.

Seasonality

Most commonly observed in May, then again in August and September, coinciding with peak abundance in spring and fall.

Diet

hunt (: ) as for . Prey is paralyzed or crushed and transported to nest. One observed female of a related (P. lethifer) provisioned a with 89 aphids. Adults may also feed on aphids directly and occasionally visit flowers.

Host Associations

Aphididae - primary food source for

Life Cycle

Solitary nesting. Female constructs nest in pre-existing cavity or tunnels through pith. Creates linear series of separated by partitions of chewed pith or sawdust. Each cell provisioned with 10 to several dozen before deposition. Egg placement variable—at back of cell or midway. consumes stored prey, pupates within cell. Some create branching tunnels in wider twigs rather than linear series.

Behavior

Highly active, rapid makes observation difficult. Female hunts at colonies, plucking from stems and leaves with . Can evade guards through speed—ants typically cannot react before exits. Males may wait outside nest tunnels for emerging females to mate. Female sometimes guards nest entrance against and competitors. Small (Ceratina spp.) may destroy Pemphredon nests to usurp cavities.

Ecological Role

of , potentially contributing to aphid . Serves as for cleptoparasitic (Omalus spp., Holopyga spp.) that lay in aphid ; when Pemphredon transports parasitized aphid to nest, cuckoo wasp develops instead. Also parasitized by ichneumon (Perithous mediator), (Anthrax irroratus), and satellite (Senotainia trilineata).

Human Relevance

as agent for pests. Can be attracted to gardens by providing artificial nesting : blocks of wood with small-diameter holes (2-4 mm) hung under protected eaves. Commercial solitary lodges can be modified for this purpose. Rarely ; solitary generally sting only if handled.

Similar Taxa

Philanthus gibbosusbeewolf that preys on and including Pemphredon; larger with more build, different and nesting
Trypoxylon frigidum-hunting crabronid found at same colonies but taking spiders rather than aphids; different and nest provisioning
Ceratina spp.small that compete for same pithy-twig nesting sites; have pollen-carrying structures and different