DIGITAL FIELD GUIDE: WASPS (Order: Hymenoptera)
Glenostictia sp.
<-- from Key Location 17c
Identification features: There are at least two species of Glenostictia in the Gardens, and they look very much alike: Glenostictia clypeata and Glenostictia pictifrons. These wasps are about three-quarters of an inch long, without pubescence (hairs), and boldly colored yellow and black. The abdomen is black with wide, undulating or notched yellow bands that meet in the middle. The thorax is black with various yellow accenting, the most noticeable of which is a “horse shoe“ pattern. The names of the two species found in the Gardens suggest that early entomologists considered the facial areas of these wasps distinctive. The specific epithet “clypeata” refers to the clypeus, or nose, which in Glenostictia clypeata, is large and yellow. The specific epithet “pictifrons” means painted face; the face of Glenostictia pictifrons is bright yellow and accented with short pale hairs that glitter silver in the sun. These characters, as well as the undulating abdominal patterns will distinguish Glenostictia from the similar sand wasp, Bicyrtes.
These sand wasps are robust, brightly colored, and fast, agile fliers. They hover around flowers and their nests, hanging motionless in the air except for wings moving so quickly they make a noticeable buzzing sound. In fact, you might locate the wasp by hearing it before you see something bright yellow zip past.
Nesting habit and prey: Glenostictia is a sand wasp, and as this common name suggests, nest building is in sand and sandy soils. Females dig the nests and lay the eggs. Although they are solitary, they tend to nest in aggregations, perhaps because appropriate soil conditions are relatively scarce. Females have a special structure on their front legs, a foretarsal rake, used to scrape sand during nest building. Glenostictia provisions her nest with adult flies, particularly bee flies (Bombyliidae). She hunts them, stings them—paralyzing, but not killing them—then carries them back to the nest. After packing several flies into the brood cell and she lays an egg on one. Unlike many other wasps, she continues to provision the nest even after the larval wasp hatches.
Glenostictia as pollinator: As an adult, Glenostictia feeds on flower nectar. This wasp has a long tongue and is not restricted to shallow flowers. It has been observed nectaring on the tubular flowers of butterfly bush and bee-brush (Aloysia) as well as the shallow flowers of Texas kidneywood, and various composites.
Glenostictia clypeata
