Euodynerus foraminatus

The species can be recognized as a member of Euodynerus by its robust, somewhat blocky body form typical of the genus. Specific diagnostic features distinguishing E. foraminatus from similar species such as E. hidalgo or E. annulatus are not documented in available sources. Nests are identifiable by mud partitions between cells and a final mud plug sealing the entrance.

Utilizes pre-existing cavities in wooden structures, including holes in dead wood, abandoned solitary bee burrows, and artificial bee blocks. Has been observed nesting in both outdoor and indoor wooden structures, including building walls and shelving systems.

Transcontinental in North America: recorded across the United States from coast to coast, all Canadian provinces, and south into Mexico.

Adults active during warmer months; larvae complete development and emerge as adults approximately one year after nesting, with emergence typically occurring in June.

Adults feed on nectar from flowers. Larvae are fed paralyzed caterpillars, specifically larvae of moths in the families Oecophoridae, Tortricidae, Gelechiidae, Pyralidae, and Crambidae (subfamily Pyraustinae).

• Lepidoptera - predatorFemales paralyze caterpillars to provision nest cells for larval offspring

Females construct linear series of cells within pre-existing cavities, each cell stocked with multiple paralyzed caterpillars. An egg is laid on the first or last caterpillar in each cell, followed by construction of a mud partition. Multiple generations may be produced per year in some regions. The egg and larval stages complete in approximately 7-9 days; pupal development takes about 14 days for males and 19 days for females. Adults emerge from pupae after approximately one year, leaving an exit hole in the mud plug.

Solitary nesting behavior; females hunt caterpillars, paralyze them with venom, and transport them back to nest cavities. Visits flowers for nectar. Will occupy artificial nest structures such as bee blocks with holes of appropriate diameter. Nest entrances are sealed with mud plugs upon completion.

Biological control agent of caterpillar pests, particularly those that conceal themselves in rolled or tied leaves that other predators avoid. Contributes to pollination through nectar-foraging activity.

Beneficial for garden pest control through predation on caterpillars of pest moth species. Readily attracted to artificial bee blocks, providing opportunities for observation and biological control in residential settings. Does not defend nests aggressively and poses minimal stinging risk to humans.

• Euodynerus hidalgoBoth are widespread transcontinental mason wasps with similar body form; E. hidalgo has a strong carina on the front edge of the pronotum and thin, slightly upturned hind margins on the second and third abdominal tergites
• Euodynerus annulatusSimilar size and distribution; E. annulatus excavates burrows in soil rather than using pre-existing cavities and constructs distinctive curved mud chimneys above ground

• solitary
• cavity-nesting
• predator
• biological control
• pollinator
• mud-nesting

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Bug Eric: The Mason Wasp Euodynerus foraminatus Endorses Bee Blocks
• Bug Eric: Wasp Wednesday: Euodynerus annulatus
• Bug Eric: Wasp Wednesday: Euodynerus hidalgo
• Inbreeding in a natural population of Euodynerus foraminatus (Hymenoptera: Vespidae), a solitary wasp with single‐locus complementary sex determination