DIGITAL FIELD GUIDE: WASPS (Order: Hymenoptera)
Steniolia elegans
<-- from Key Location 20b
Identification features: We found just one species of this wasp in the Gardens. Steniolia elegans is a large (about three quarters of an inch long), boldly-colored black and yellow sand wasp. The abdomen is black with wide, undulating, yellow bands which form yellow tear-drop shapes where the bands do not quite meet in the middle. The thorax is black with a simple, not smiling yellow face pattern. Steniolia has large green eyes and its nose (clypeus) is covered in short pale hairs that glitter silver in the sunlight.
This sand wasp is a fast, agile flier and hover around flowers, hanging motionless in the air. Her wings beat so fast that you cannot see them, but you may hear a noticeable buzzing sound as she moves from flower to flower.
Nesting habit and prey: Sand wasps nest in sand and sandy soil. They are solitary, but tend to nest in aggregations, perhaps because appropriate soil conditions are scarce. The females dig shallow holes using a special structure on their front legs called a rake to whisk sand out of the way. Steniolia provisions her nest with adult flies, particularly bee flies (Bombyliidae). After packing several flies into the brood cell, she lays an egg on one fly, then seals the nest. Unlike many other wasps, she continues to provision the nest even after the larval wasp emerges.
Steniolia as Pollinator. As an adult, Steniolia feeds on flower nectar. This wasp has a long tongue and is not restricted to shallow flowers. It has been observed nectaring on turpentine bush, green thread (Thelesperma), lacy tansy aster (Machaeranthera), desert zinnia, gaillardia, and horehound.
