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Forester Moth Credit: Paul Wilkinson YDNPA

Rare Moths in the Dales

Barred Tooth-striped Moth

Trichopteryx polycommata

The barred tooth-striped is a moth of limestone and chalk areas with open woodland and scrub where wild privet (Ligustrum vulgare) occurs.

This is a nationally scarce-A moth with only two known sites in Yorkshire both of which are in the Yorkshire Dales National Park.

The adults are nocturnal and on the wing between mid March and late April.  Eggs are laid in April and the pupas overwinter in the soil.

The threats to this moth are from habitat destruction and the change in existing habitat quality.

Wild privet is understood to be the main food plant for the larvae but larvae have been recorded using ash (Fraxinus excelsior).  Ash of course is (even with ash dieback disease) widespread in the national park so further work with moth trapping may reveal other sites for this species in the Dales.  In the Yorkshire Dales National Park we have very few woodland sites that contain wild privet and so we are working with partners to increase the numbers of these plants in the limestone woodlands of the Dales.  An increase in wild privet should help safeguard the current populations and enable them to spread in to new areas and buffer the potential impacts from ash dieback disease.

Forester Moth

Forester Moth

Adscita statices

This moth is a scarce and local species in Yorkshire with only one known site in the national park.

This day flying moth is on the wing from May to July and uses common sorrel (Rumex acetosa) and sheep’s sorrel (Rumex acetosella) for its larval food plant.

This species can easily be confused with the more widespread Cistus forester (Adscita geryon) which is only slightly smaller than the forester.  The larval food plant for the Cistus forester is common rock rose (Helianthemum nummularium) therefore the habitat preferences are different but, as with the site in the Dales, it is still possible to have the two species on adjacent habitats.

The requirement for open habitats with sorrel species should makes this moth more widespread than it is.  Work is ongoing to try and identify other sites in the Dales which may hold as yet undiscovered populations of the forester moth.

Tissue Moth

Triphosa dubitata

Nationally this moth species has a local distribution but in Yorkshire the tissue moth is rare and very local.

This moth seems to have a significant population, relatively speaking, within the limestone areas of the Yorkshire Dales.

The tissue moth hibernates over winter as an adult using the many caves that are present in the Dales; they emerge in spring and seek out purging buckthorn ( Rhamnus cathartica) to lay their eggs on.  The tissue moth will use alder buckthorn (Frangula alnus) which grows on acidic soils but larvae collected in the Dales don’t seem to be interested in it.

It would seem that declining habitat quality and fragmentation are important factors in the decline of this species and consequently its local distribution.

Open scrubby places and woodlands on limestone and chalk are key habitats with the presence of purging buckthorn (on limestone) being essential in providing, as far as we know, the only food plant for the larvae.

We are running a project to propagate plants from the remaining mature shrubs in the national park so that they can be planted out across the limestone areas of the Dales which should safeguard the current population of tissue moth and enable it to expand.