Berberis Sawfly - Arge berberidis

Description

The adult is very dark - metallic blue in a good light. It has dark legs (distinguishing it from Arge ustulata), smoky wings which lack a wing cloud.

Similar Species

Arge ustulata is the only other dark bodied Arge recorded in VC55 so far. This has pale legs and a wing cloud.

Identification difficulty
ID guidance
  • dark bodied (metallic blue)
  • all dark legs
  • tinted wings without a wing cloud
  • black hairs on face
Habitat

To be found on berberis and mahonia plants.

When to see it

June to August

Life History

Berberis sawfly larvae cause severe defoliation on some berberis and mahonia spp. in Britain. They have a black head on a greyish-white body with yellow blotches and small black dots.

UK Status

First British record was in Essex in 2002, since when it has been recorded in most southern counties, and has reportedly now reached Yorkshire.

VC55 Status

Previously uncommon in Leicestershire and Rutland, its numbers now seem to be increasing.

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Leicestershire & Rutland Map

MAP KEY:

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

UK Map