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NEWS RELEASE No: 1347631 MARCH 2010

Have you seen this moth?

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Pine-tree lappet moth

The Forestry Commission is appealing topeople out and about in the Inverness-shire countryside this summer to look out for pine-tree lappet moths and let it know if they see any.

A population of the species, which could potentially cause serious damage if numbers increase, has been found breeding in pinewoods west of Inverness, including the Commission’s Boblainy Forest.
Although occasional individuals have turned up in southern England, pine-tree lappets have never previously been found breeding in Britain, so the species might be a recent arrival or a previously undiscovered resident.

The pine-tree lappet (Dendrolimus pini) is a native of continental Europe, Russia and Asia, where the caterpillars feed mostly 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. Many trees die during severe outbreaks because the defoliation makes them susceptible to diseases, bark beetles and wood-boring insects.

Roddie Burgess, head of the Commission's Plant Health Service, explained,

"We are continuing research to try to determine the likelihood of pine-tree lappet being a previously unknown native species or a recent arrival in Scotland and, more importantly, 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 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.

"Meanwhile, we are appealing to people who are out and about in the area, such as walkers, anglers, bird-watchers, farmers and foresters, many of whom are keen observers of local wildlife, to keep an eye out for them this summer and report any sightings to us. This information will help us to keep track of their geographical spread and inform any decisions we might need to take.”

Mr Burgess added that it would be very helpful to the Commission to also receive digital photographs of any specimens seen, and any captured specimens if possible, for expert confirmation of their identity.

Reports of sightings, and any photographs, should be accompanied by a precise description of the spot where they were sighted or captured - preferably an Ordnance Survey grid reference.

Anyone who has captured a specimen should send a photograph and location report in the first instance, and meanwhile place the moth in a secure, rigid plastic container and telephone or email the Forestry Commission contact below for instructions about how and where to send it.

Pine-tree lappet is a large moth: the males have a wingspan of about 60mm (2.5 inches), while the females are larger at 80mm (3.2 inches). Males are a greyish or reddish brown with a white central spot in the middle of the wing and a jagged-edged band across the wing.

They are most likely to be found in or near woodland with a significant proportion of Scots pine trees, but they are also known to feed on other conifers common in Scotland, including Sitka spruce (Picea sitchensis), Douglas fir (Pseudotsuga menziesii), larch (Larix spp.) and lodgepole pine (Pinus contorta).


  1. The investigations were prompted by the discovery of a small number of male pine-tree lappets in the area in 2008, following discoveries of one in 2004 and two in 2007, which were not reported to the Forestry Commission at the time. The presence of a breeding population was confirmed in 2009 when larvae (caterpillars) and a cocoon were found. If the species is a recent arrival, there are a number of possible routes by which it might have been introduced. They might have been brought in on imported pine trees, or in association with wood products, wood packaging or vehicular machinery. However, the colonisation route has not yet been identified, despite extensive Forestry Commission investigations. Accidental or deliberate release is another possibility that cannot be ruled out.
  2. Results of DNA testing by scientists from the Forestry Commission’s Forest Research arm on a small sample of the Inverness-shire moths revealed very little genetic diversity among them. This could mean either that the population was recently founded by a small number of recently arrived individuals, or it is the early stages of the recovery of a longer-established population that for some reason had collapsed to very small numbers at some point in the past. The scientists are doing more-extensive DNA testing to obtain more-conclusive results. In particular they hope to match the mitochondrial (maternally inherited) DNA with that of populations of the moth on the Continent - the further from Scotland the nearest matching population is, the less likely it is that the Scottish moths arrived by natural means.
  3. A key part of the research is looking at the potential impact of climate change on the moths' potential to cause damage. Some parts of Scotland, particularly eastern Scotland, are predicted to experience drier summers as the climate changes. Evidence from Poland and Germany indicates that the worst damage is caused to forests on sandy soils after cold winters and hot, dry summers, when the moths' population tends to expand considerably.
  4. Scotland's forests are estimated to be worth 800 million a year in products and services such as timber, venison, tourism, recreation and other benefits. A high proportion of Scotland's forest area is dominated by the species of trees preferred by pine-tree lappet, so if it does become a pest there could be a significant risk to jobs and businesses, particularly in economically fragile rural areas. Pine forests are also the habitat of a number of iconic species, including capercaillie, red squirrel and Scottish crossbill.

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