Oxybelus uniglumis (Linnaeus,1758)
Description and notes
This is the most common of our Oxybelus species.
Showing a female at her burrow. Emerging from the burrow, then concealing the entrance, and next bringing in prey - a fly impaled upon her sting. Video provided by Jason Burton.
Widely distributed in England, but rare in southern Scotland and sporadic in Ireland, where it seems to occur on or near the coast. The map illustrates a species which is grossly under-recorded.
Status (in Britain only)
This species is not regarded as being threatened.
Usually associated with open patches of bare, loose sand (it has even been observed in sand bunkers on a golf course). It also occurs on heavier soils, for example in open woodland.
The species is univoltine, flying from early June to mid-September.
Diptera, mostly muscids.
Many observations have been made on the nesting behaviour of this species (Hamm & Richards, 1930; Boreham, 1956a; Peckham, Kurczewski & Peckham, 1973; Peckham & Hook, 1980). The following observations were made by J P Field at a small sandpit on the edge of Sunningdale Golf Course, Surrey. The wasp burrows in flat or sloping (not vertical), bare, sandy soil. The oblique burrows are 2-12 cm long and take about two hours to dig. At the end of digging, the female quickly closes her nest by scraping sand into the entrance, and begins hunting. Prey is captured in mid-air and on vegetation, and stung once in the thorax behind a front leg base (Steiner, 1979). Females fly to a spot near the nest with the prey carried under the body; then the prey is impaled on the sting for the last metre or two (very unusual in solitary wasps). Nest provisioning is described and illustrated by Olberg (1959). Each cell is provisioned with 2-16 paralysed flies, the number depending partly on their size. Provisioning a cell takes about 90 minutes. After taking the last fly in, the female arranges the flies in the cell, oviposits on them, then digs the next cell. There are usually two or three cells in a nest. The most successful females can provision 34 cells in a day.
Females of the parasitic miltogrammine fly Senotainia conica wait close to Oxybelus nests, continually looking in different directions for arriving wasps. The Senotainia runs into the nest behind the Oxybelus then flies out a second later, probably after depositing a single maggot directly on to the impaled fly. The maggot destroys the Oxybelus egg then feeds on the prey. Two other British miltogrammines, both Metopia species, may also be seen. The females larviposit into open aculeate burrows instead of following provisioning females. Oxybelus nests are protected by being closed whenever the female is away hunting, so the only opportunity a Metopia has is during the few seconds between the wasp entering with a fly and leaving again.
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