Euodynerus annulatus arvensis
(de Saussure, 1869)
Euodynerus annulatus arvensis is a of the mason wasp Euodynerus annulatus, one of five subspecies of this widespread North American . Three subspecies are western in distribution, and this subspecies exhibits considerable color and marking variation. Females construct distinctive burrows with curved mud chimneys above ground, provisioning with paralyzed caterpillars from several .
Pronunciation
How to pronounce Euodynerus annulatus arvensis: //juː.oʊˈdaɪnərəs ˌæn.jəˈleɪ.təs ɑːrˈvɛn.sɪs//
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Identification
Distinguished from the very common Euodynerus hidalgo by the less angulate propodeum and non-reflexed (not turned up) hind margins of the first and second abdominal tergites. Males recognized by hooked tips. As one of three western , geographic location may assist identification, though subspecies-level identification requires expert examination.
Images
Appearance
As a of Euodynerus annulatus, individuals show considerable variation in color and markings. The is fairly large for a mason wasp, with forewing length of 8.5-10.5 millimeters. Males can be recognized by hooked tips of the and less robust body compared to females. The propodeum (hindmost thoracic segment) is less angulate than in the similar species Euodynerus hidalgo, and the hind margins of the first and second abdominal segments are not reflexed upward as in that species.
Habitat
Found in varied situations near water, as females require water to soften soil during nest construction. Tolerates both hard and soft soil types for nesting. Observed at Florissant Fossil Beds National Monument in Colorado at approximately 8,500 feet elevation, taking nectar from rabbitbrush (Ericameria sp.).
Distribution
Western North America. As one of three western of Euodynerus annulatus, which occurs coast to coast in the United States, south to Mexico, and in Canadian provinces British Columbia, Alberta, Saskatchewan, and Ontario.
Seasonality
active in summer; observed in Colorado in early July. Likely single or possibly multiple per year depending on latitude and climate, though specific data for this is lacking.
Diet
Host Associations
Life Cycle
Females excavate burrows in soil and construct curved mud chimneys extending above ground. Several branch from the main underground burrow. A single is suspended from a short thread attached to the cell wall before provisioning with caterpillars. The chimney serves both defensive purposes and as a source of mud pellets for final nest closure. After provisioning all cells, the entrance is sealed and the female departs to begin a new nest. The turret is eventually deconstructed entirely, rendering the nest entrance nearly invisible and flush with surrounding soil. Developmental timing unknown for this specifically.
Behavior
Females excavate burrows rather than using pre-existing cavities, extending tunnels above ground as curved mud chimneys. They regurgitate water to soften soil during construction. visit flowers for nectar. No nest recorded, though adults are vulnerable to the twisted-wing parasite Pseudoxenos hookeri, evidenced by abdominal bulges with bullet-like structures between segments.
Ecological Role
of caterpillars, potentially providing of pests including alfalfa webworms and related . As a nectar visitor, may contribute to pollination. Serves as for twisted-wing parasites (Strepsiptera).
Human Relevance
May be attracted to blocks and nesting structures designed for solitary bees and . Potential agent for caterpillar pests in agricultural and garden settings. No negative impacts documented.
Similar Taxa
- Euodynerus hidalgoVery common and widespread; distinguished by more angulate propodeum and reflexed (turned up) hind margins of first and second abdominal tergites
- Euodynerus annulatus (other subspecies)Four other exist; E. annulatus arvensis is one of three western subspecies with variable coloration requiring expert identification
More Details
Nest architecture
The curved mud chimney constructed by females is unusual among mason wasps and serves multiple functions: defense against , source of mud for final nest closure, and possibly .
Taxonomic note
This was originally described by de Saussure in 1869. The Euodynerus annulatus was historically known as Odynerus geminus in early literature (Rau and Rau, 1918).