Forestry investigators and moth experts in Scotland have discovered a number of pine-tree lappet moth larvae and a cocoon, indicating that the species is breeding.
Pine-tree lappets had not previously been recorded in Scotland, so the species might be a previously undiscovered resident, or a recent arrival. It had previously only been recorded in Great Britain from a handful of sightings over several decades of individual males in southern England. These are believed to have been migrants from Europe.
Using pheromone and light traps, sticky bands around trees and searching in the ground litter, Forestry Commission investigators and amateur moth recorders have discovered about 100 adults, some caterpillars and a cocoon since the summer in woodlands west of Inverness. These include Forestry Commission Scotland's Boblainy Forest.
The investigations were prompted by the discovery of a small number of male moths in the area last year, following discoveries of one in 2004 and two in 2007, which were not reported to the Forestry Commission at the time.
The pine-tree lappet (Dendrolimus pini) is a native of continental Europe, Russia and Asia, where the caterpillars feed primarily on Scots pine needles. The Forestry Commission is concerned that it could become a pest in this country.
Its populations can increase significantly from time to time in parts of its range in Europe, leaving large areas of pine woodland stripped of foliage as the caterpillars feed on the needles. Many of the trees die during severe outbreaks because the defoliated trees become susceptible to diseases, bark beetles and wood-boring insects as a consequence.
Forestry Commission plant health service head Roddie Burgess explained: "We are now doing further research to try to determine the likelihood of pine-tree lappet being a previously unknown native species or a recent arrival in Scotland, and to assess whether it poses a serious risk to Scotland's pine and spruce forests.
"If the evidence points to the balance of probability being that it is most likely a recently introduced species and that it does pose a risk, we will look at the best way of taking early action to prevent it spreading further afield and potentially causing serious damage to our woodland environment and forest industries."
Anyone who thinks they have seen a pine-tree lappet should contact Forestry Commission Scotland, by email to email@example.com or by telephone to 0131 314 6156, giving as precise a description of the location as possible — an Ordnance Survey grid reference is ideal.
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