Ash feeding moths

Tony Simpson

There has been speculation about the possible effects of Ash “Die Back” on our insect populations and I thought some information on local moths associated with this tree would be of interest.

Ash has few associated moths probably because it is a chemically well protected species and the larvae feeding on it need to be highly specialised to cope with this. Some Ash feeders also feed on related Privet species which are also in the Oleaceae family, as are Forsythia and Lilac.

Amongst the larger moths the common Centre-barred Sallow Atethmia centrago overwinters as an egg and feeds, mainly on the flowers, in the spring. Similarly the larva of the Dusky Thorn Ennomos fuscantaria feeds exclusively on this tree, as does the more uncommon Tawny Pinion Lithophane semibrunnea.

Amongst the micromoths the uncommon Zelleria hepariella feeds in a web on the young leaves in June; the common Prays fraxinella mines leaves and shoots causing drooping of young leaves in the spring; the recently separated Prays ruficeps also feeds in a web on leaves as well as mining shoots; the common Pyralid, Euzophera pinguis, feeds under the bark of mature trees, as does the rare Tortrix, Pammene suspectana.

All these species are therefore likely to be seriously affected.

The recently spreading Coronet Craniophora ligustri seems mainly to feed on Ash but is said to also feed on Privet. Ash Pug Eupithecia fraxinata is nowadays usually considered to be a form of Angle-barred Pug Eupithecia innotata which has coastal populations on Sea Buckthorn and Tamarisk in the U.K, but inland it is a rare Ash feeding resident with only three confirmed modern Worcestershire records. The nationally rare Barred Tooth-striped Trichopteryx polycommata feeds on Ash as well as more usually on Privet, but our last local record was in 1979. I have seen Privet Hawk Moth Sphinx ligustri larvae on Ash in West Wales but Privet is the usual food plant and we have only two modern records of this species.

The common micromoths Caloptilia syringella (also on Privet and Lilac) and Pseudargyrotoza conwagana (also in berries of wild Privet) are Ash feeders, as is Caloptilia cuculipennella (also on Privet) a recent arrival in the county.

It is possible loss of Ash will significantly affect these species but as they do apparently have alternative food plants they may not be so seriously affected. A lot will depend on how quickly and completely Ash is lost from the environment.