Microterys nietneri

The tiny encyrtid wasp Microterys nietneri is very distinctive in appearance, being mainly orange-brown, but with strongly patterned wings and antennae which are black and white at the tips. Despite its striking appearance there are similar species and great care is needed with identification. Microterys nietneri and Microterys seyon are similar in appearance with strongly patterned wings and black and white antennae. The middle tibia of Microterys seyon is covered in silky hairs which are not present in M. nietneri . Also, the pale section of the antennae is clear white in M. nietneri but off-white in M. seyon. Microterys tricoloricornis is slightly larger (nearly twice the size, around 4mm) and darker than the other two species. 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. We suggest recorders seek expert confirmation before adding records for this species. It has been introduced around the world as a biocontrol agent against some soft-scale, greenhouse pests and seems to have escaped in Britain to seek soft-scale insects on various vegetation in the wild. Most likely to be swept from shrubs and bushes in the summer months. Certainly in the past it could not have survived outside of greenhouse conditions because it is really a warm-climate species. It had turned up in the London area by 2019 and may be unrecorded in other areas. Possibly introduced accidentally with these greenhouse pests from places like the Netherlands, although it may also have found its own way here.