Shiny-vented Sharp-tail Bee - Coelioxys inermis


One of three Coelioxys species with similar tips to the female's sternite 6 (two sharp teeth on either side near apex).

Similar Species

Females are more easily determined than males and can be separated from female C. mandibularis by the shape of the mandibles; from C. elongata by the shiny, punctate sternite 4 which contrasts strongly with the duller sternite 5 (sternite 4 dull, shagreened and mostly impunctate in elongata). The apex of tergite 5 is bluntly pointed (a shallow notch is present in elongata).  

Males of these three species are challenging and any records would need to be confirmed by a national expert for confirmation.

Identification difficulty
Recording advice

Unless identified by a recognised expert, a photo is required and the specimen should be examined with a microscope. In the comments box, state the key or ID method used and describe the size and identifying characters.


Found in the same habitats as its hosts, though it appears to be found more frequently in dune systems at coastal sites than at inland locations.

When to see it

It is on the wing from late June or July to August.

Life History

This species is a cleptoparasite of Megachile maritima and M. centuncularis. The females of all but one British species of Coelioxys have a pointed sixth tergite and fifth sternite which is apparently used to cut open the cell wall or cap of the host species. An egg is laid in this slit with at least one third protruding through into the cell or laid directly onto the host egg. There is currently no data to suggest which method C. inermis employs. Generally, Coelioxys larvae kill, and in some species eat, the host egg immediately on hatching. Pupation occurs within a cocoon spun within the host cell where the larva overwinters as a pre-pupa, prior to final pupation, presumably in spring of the following year.

UK Status

Largely a southern species, appearing to favour the south-east of England but also the south coast of Wales. There are sporadic records from the south-west northwards to Cumberland and Yorkshire.

VC55 Status

Status in Leicestershire and Rutland not known.

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Leicestershire & Rutland Map


Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

UK Map