Thanks to a small grant from National Parks and Wildlife Service I was able to survey leaf mining Lepidoptera in the Republic of Ireland. Although my focus was on the border counties where leaf miners are seriously under recorded I kept the brief broad. This allowed me to travel to Meath and Dublin where I teamed up with my old friend Eamonn O’Donnell and his partner Kerri Gorentz. One of our search areas was to be the Botanic Gardens and Cemetery at Glasnevin, Co Dublin. These places are usually good for leaf miners with an array of exotic, non-native trees and shrubs. I was also well aware of the recent discovery of Ectoedemia heringella on evergreen oaks Quercus ilex at the Botanic Gardens.
E. heringella was easily found in both the Gardens and cemetery. Typically, it is already abundant with multiple mines on many leaves. I knew from looking at leaf mines in France and London that another species could also occur on these trees, S. suberivora, but that finding it has become much harder because of the density of heringella mines which can obscure it.
After about fifteen minutes of searching I found what I believed to be two mines of suberivora. Both were on leaves lacking heringella mines. The heringella mines are small ad compact taking up on average less than a square cm whereas the two suberivora mines were long (just over 4cm) and along the leaf margin. Mines of both were packed with black frass and egg upper in both cases. Without backlighting the mines are buffish in colour. As heringella increases in numbers, which it will, then suberivora is likely to become increasingly difficult to locate. A number of UK experts concurred with the identification.
Mines of E. heringella
Mine of S. suberivora (backlit)
The same mine without backlighting
Dave Allen July 2022