Steniolia elegans
J. Parker, 1929
sand wasp
Steniolia elegans is a solitary sand wasp in the Crabronidae. Females dig burrows in dry, powdery soil and provision them with paralyzed flies for their single offspring. The exhibits , with females repeatedly hunting and delivering prey throughout larval development. Both sexes form dense, spherical sleeping clusters at night where mating occurs.
Pronunciation
How to pronounce Steniolia elegans: /stɛˈniːɔliə ɪˈleɪɡænz/
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Identification
Ornately marked with distinctive coloration. Males possess long, tongue-like mouthparts (elongated and ) adapted for reaching nectar in deep flowers; these structures are not retractable and are tucked between the legs when not in use. Females are smaller than males. Among fourteen North American Steniolia , all are western in distribution.
Habitat
Dry, powdery soil in open areas; nesting sites often in close proximity to one another. Found in western North American from arid regions to montane areas.
Distribution
Western North America: from southeast Washington, Idaho, and Wyoming south through much of Mexico. Also recorded from Central America.
Seasonality
active during warmer months; specific period not well documented but observed in June in Arizona.
Diet
Females hunt primarily bee flies (Bombyliidae) and flower flies (Syrphidae) as larval provisions. of both sexes feed on nectar; males frequent flowers such as thistles where their elongated mouthparts can access deep nectar sources.
Life Cycle
Females dig burrows 7-17 cm deep terminating in a single . An is laid on the first paralyzed fly placed in the cell; the female continues to provision the developing larva with additional flies throughout its growth (). When the larva stops feeding, the female seals the burrow permanently and departs to start a new nest. The larva pupates and emerges as an weeks later, or overwinters if pupating in autumn.
Behavior
Solitary nesting, though females often aggregate in loose colonies with nests in close proximity. Females cover burrow entrances while away hunting and use subtle landmarks to relocate nests. Both sexes form dense, spherical sleeping clusters at night that disperse at daybreak; mating occurs at these .
Ecological Role
of dipteran flies. Serves as for parasitic velvet ants and the cuckoo wasp Parnopes edwardsii. Nesting may influence local soil structure.
Similar Taxa
- Steniolia eremicaSimilar appearance and ; S. eremica males are larger (ca. 22 mm), described in 1964, and range from central Nevada to Mexico. S. elegans has broader distribution extending to Washington and Wyoming.