An increasing number of new moth species are arriving and settling in the UK as a result of the global reach of the horticultural trade and the changing climate, moth experts have revealed.

Almost 30 new species of pyralid moth have been recorded in the UK in the last 30 years with eight becoming established residents, wildlife publisher Atropos and charity Butterfly Conservation said.

Pyralid moths include some of the largest and most distinctive of the 1,600 species of micro-moths found in the UK. Around 900 species of generally larger and better known macro–moths are also found here.

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Musotima nitidalis. Photo: Les Hill, Butterfly Conservation

The North Sea and English Channel provide a natural barrier to many potential colonising species, but the horticultural trade can provide a route into the UK with moth eggs, caterpillars or even pupae hitching a ride on imported plants.

Climate change is also altering conditions enabling moths to take advantage of habitats in new areas.

This recent increase in new species comes at a time when many of the UK’s moths are in decline as a result of habitat loss and agricultural intensification.

As part of this year’s Moth Night, an annual UK-wide event to record and celebrate moths, organisers Atropos, Butterfly Conservation and the Centre for Ecology & Hydrology are asking the public to look for pyralid moths in their gardens, the countryside and at specially organised moth trapping events.

Pyralids are often under-recorded so scientists need new records of sightings to determine how these moths are faring across the UK and to spot any new species that have arrived.

The moth Musotima nitidalis, originally from Australia and New Zealand, is thought to have arrived in the UK in 2009 as a result of the horticultural trade. The moth is now found in several locations in southern England where its caterpillars feed on ferns such as Bracken.

Many of the recent pyralid colonists have arrived naturally, probably assisted by climate change, including the beautifully coloured Evergestis limbata. This species has now settled along the south coast of England after first being recorded in 1994.

Easy to see native pyralids include the day-flying Mint Moth, which can be found in garden herb patches as well as in open grassland habitats.

The distinctive black and white Small Magpie and the Mother of Pearl which sports a pearly sheen on its upper wings can also be found in gardens or near nettle patches. Common migrants to look out for included the Rush Veneer and Rusty-dot Pearl.

Another group of pyralid moth, the China-marks, are found in wetlands, their caterpillars living in an air-filled bubble of spun leaves at or just under the water’s surface in ponds and at the edges of streams.

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Scarce Crimson and Gold (Pyrausta sanguinalis). Photo: Marcell Kárpáti, Butterfly Conservation

Several pyralids are rare and threatened in the UK including the White-spotted Sable, a declining species of woodland glades and hillsides, and the Scarce Crimson and Gold, which is thought to occur in sand dunes habitats in Northern Ireland, but still survives on the Isle of Man, having been lost from England and Scotland.

Butterfly Conservation associate director of recording, Richard Fox said: “Moths are often portrayed as boring, brown and impossible to identify but pyralids explode these myths with simply stunning species such as the Scarce Crimson and Gold and amazing life histories, such as the Beautiful China-mark, whose caterpillars live under water.”

Moth Night 2018 runs from June 14-16 and includes moth trapping events across the UK.