Ruby-tailed wasp  (Chrysis pseudobrevitarsis)

This very rare species is classified as Vulnerable in Britain (2).

This vulnerable and beautiful ruby-tailed wasp has a striking appearance. As the common name suggests, it has a brilliant ruby-coloured abdomen and the thorax is iridescent and brightly coloured. It is a parasitoid of the scarce eumenid wasp Ancistrocerus antilope (1) .

Definite confirmed records of this species have occurred in Northamptonshire in 1947, and north Devon from 1979 to 1985, and again in 1989 (2). An old record has been reported for Woking in Surrey, but this has not been confirmed, and the host wasp is not found in this area (2).

You can view distribution information for this species at the National Biodiversity Network Gateway.

The host is found in a range of habitats, but seems to have a preference for old buildings with loose or crumbling mortar and sandy and earthy banks, in which it nests (2). It is also associated with farmyards and derelict stone buildings (2).

This ruby-tailed wasp is a parasitoid of the host eumenid wasp (Ancistrocerus antilope) larvae. Females lay their eggs in the host larvae; the eggs hatch out and the larvae of the ruby-tailed wasp then develop inside the host. The host wasps lays their eggs inside cavities in walls, holes in earthy or sandy banks and in old beetle burrows in wood, and provide small caterpillars as a food source for the young. Adults of this species of ruby-tailed wasp have been recorded from May to July (2).

This rare ruby-tailed wasp appears to be vulnerable to changes in the populations of its host. Other potential threats include the decrease in availability of old buildings with crumbling mortar, dead wood and sandy or earthy banks. Agricultural intensification and increasing urbanisation may also be problems (2).

At known sites for this species, old stone buildings and walls, and sandy or earthy banks should be preserved to retain suitable nesting sites for the host wasp. Management may be needed to keep natural succession in check (2).

There may be further information about this species available via the National Biodiversity Network Gateway.