Red Pea Gall Wasp - Cynips divisa

Alternative names
Pea Gall
Description

Cynips divisa is a Cynipid gall wasp that causes galls to form on Pedunculate and Sessile Oak. These galls are more likely to be seen than the adult wasps.

The Red Pea Gall is caused by the agamic generation on the underside of the Oak leaves.  The point of attachment may show as an indistinct spot on the leaf upperside. It is spherical, up to 6mm diameter, has a smooth surface, and is hard (not succulent).   The gall is thick-walled and hard to crush, with a circular chamber inside.

The sexual generation gall can be found in the leaf, or sometimes in buds or catkins; it is inconspicuous so less often seen.

Similar Species

The gall can be similar to those caused by other species such as Neuroterus anthracinus, Cynips longiventris and Cynips quercusfolii. 

Identification difficulty

Agamic gall Sexual Gall Adult

ID guidance

When recording the gall please provide good close ups (a side-on view), and an indication of size.  It is helpful to section the gall to look at inner structure.

Check for the presence of tissue flaps, or 'saddle' to eliminate Neuroterus anthracinus.  

Habitat

Anywhere that the host trees grow

Life History

Cynips divisa has a life cycle which encompasses a sexual generation as well as an agamic (all female with no need to mate) generation. The two generations cause different galls in different locations of the Pendunculate Oak trees (see above)

UK Status

Common and widespread in Britain

VC55 Status

It appears to be uncommon in Leicestershire and Rutland but is probably under recorde.

Leicestershire & Rutland Map

MAP KEY:

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

UK Map

Species profile

Common names
Red Currant Gall
Species group:
Bees, Wasps, Ants
Kingdom:
Animalia
Order:
Hymenoptera
Family:
Cynipidae
Records on NatureSpot:
21
First record:
03/08/2006 (Calow, Graham)
Last record:
05/11/2023 (Timms, Sue)

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