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Currant Shoot Borer (Lampronia capitella)

The Currant Shoot Borer (Lampronia capitella) is a very scarce moth in Britain with less than ten known active colonies. There is currently just one known site in Scotland, located in the Scottish Borders, however the adult moth can be hard to find and there is very high probability that more colonies await discovery.

The moth seems to have specific habitat requirements and we are keen to encourage surveys of other potentially suitable sites to see if this under-recorded species can be found elsewhere in Scotland. 

Habitat and Ecology

The moth's larvae are known to feed on bushes of Red Currant, Black Currant (Ribes spp) and Wild Gooseberry (Ribes uva-crispa). At the Scottish site both Red Currant and Black Currant bushes are favoured with garden escapees of Flowering Currant (Ribes sanguineum) seemingly shunned despite being present. Many of the known British sites are beside rivers under a woodland canopy and this is also true of the Scottish site. 

The adult moth is thought to fly on sunny days in May and perhaps early June. It has been observed resting on the foodplant by day, although often hidden under leaves. Egg-laying activity has been documented at the Scottish site during the mid and late-afternoon.

Eggs are laid onto developing green fruits in which the young larva then feed over the summer, perhaps causing premature ripening of the fruit. The following spring the larva resumes feeding, this time in a shoot, causing an obvious wilting of the shoot. The period of feeding in the spring is short and takes place immediately after the leaves start to emerge. 

A photo of woodland with currant bushes
Lampronia capitella habitat in the Scottish Borders

There is currently just one known site in Scotland on the outskirts of Peebles in the Scottish Borders. Historically it has been reported from many more places in Britain but has either died out or the colony has not been located. The one other previously known Scottish site was at Banchory and although the moth died out there due to habitat loss, its presence for some years did show that the moth can survive northerly latitudes. 

Identification

The adult moth is distinctive with a dark-purplish sheen to the wings which feature a a cream crossband and two large creamy spots. The moth also sports orangey-yellow head. With care the adult moth can be separated from any similar looking species in the Lampronia or Incurvaria genera. At 7-9 mm long it is not a large moth but is larger than any of the potential confusion species.

A photo of a Lampronia capitella larva poking out of a wilted shoot
Lampronia capitella larva in a wilted shoot (David Hill)

Larvae are olive green with a jet black head. If searching for wilted shoots, the most likely view of a caterpillar is the black head poking out of the shoot like in this photo. 

Identification of the foodplant

Gooseberry is readily identifiable due to the presence of thorns but at most woodland sites, the larval foodplant is likely to be Red or Black Currant. Separating these when they do not have mature fruit is a little tricky. The easiest difference to use is that Black Currant has glands on the underside of the leaf which can easily be seen with a x10 hand lens. These glands also mean that if the leaf is crushed it smells strongly of Black Currant whereas Red Currant does not smell significantly when crushed

Surveys

People surveying for Lampronia Capitella
Attendees at Lampronia Capitella workshop (Reuben Singleton)

The easiest method of finding the moth appears to be surveys for the larval feeding signs which are easy to detect early in the spring, as soon as the leaves emerge on the currant bushes. The larval feeding in the shoot causes individual leaves to wilt and droop and these leaves look much greyer than the fresh green of the other leaves. With experience, they can be detected from some distance away.

The spring larval feeding period is however very short and the wilted leaves soon drop off so surveys should be carried out as soon as the leaves appear. To confirm presence of the moth, gently peeling back the petiole of the leaf which will hopefully reveal the presence of the larva or its frass. 

A photo of a wilted shoot of blackcurrant caused by Lampronia capitella larva
A wilted shoot caused by a Lampronia capitella larva

Scottish Survey Map

The Google map below shows suggested locations for prospective surveys based upon records of the foodplants growing in riparian situations. Thanks to Stuart Bence from the Glasgow & SW Scotland branch for compiling the data for this map.

The map shows potential sites in two categories:

  • Priority 1 - desk-based surveys suggest high habitat suitability 
  • Priority 2 - desk-based surveys suggest potential habitat suitability

Getting involved

Please use the map above to help choose a survey site. The best time to look for wilted shoots is during April, particularly the 2nd and 3rd weeks of the month. This timing may be slightly later in northern Scotland and in colder areas. We would be very interested to hear of any results from surveys, including negative findings or any sightings of wilted shoots on currant bushes. 

Please report any findings from surveys using the survey form here

You can also contact David Hill at @email for further information.