Oberea oculata

Ecology and Distribution
This large, colourful and attractive beetle was formerly recorded in Cumbria, Kent and Oxfordshire, and was common throughout the East Anglian fens in the 19th century. However, since 1890 it has been found only in a small area in the Parish of Wicken, initially at Wicken Fen.

Unfortunately the beetle has not been found at Wicken Fen since the 1980s despite regular searching and appears to be extinct there. This beetle also occurs in central Europe where it is more common in mountainous areas.

However, a small colony was discovered in the early 1990s at another site in the Fens. This colony is the only known surviving breeding colony of the beetle. The precise location of the colony is a closely guarded secret in order to protect the beetles from collectors.

The beetles can be found on willow bushes between June and September.

Threats
Very little is known about the threats to this beetle but there are several suggestions. The termination of large-scale sedge cutting and peat digging in the area has encouraged Carr (wet woodland) encroachment and the loss of suitable ground for purple willow Salix purpurea establishment, particularly near open water.

Purple willow is the only tree species on which the surviving colony breeds. Land drainage has resulted in reduced water tables, which also discourages purple willow growth. Cattle are grazing/browsing up to 30% of the beetle’s suitable breeding habitat at the surviving colony each year, which not only reduces the number of breeding sites available but also removes eggs and larvae.

Current Work

• Surveying work is being carried out at Wicken and at the secret site as well as monitoring of the existing colony.
• Willow planting and habitat management work is also being implemented at the secret site in order to increase the population.

Contacts

• Dr Stuart Warrington, Nature Conservation Adviser, East of England
• Jon Webb – English Nature, Peterborough Head Office