By Stephen Palmer
The Belted Beauty moth, Lycia zonaria britannica, is an endemic subspecies in the UK and was until recently restricted to only two sites in England and one in Wales. Indications are that the Welsh population and that on the Wirral, England may well have become extinct within the last five years. Elsewhere the moth, in the form of a different subspecies, occurs on the western isles of Scotland and Ireland.
This national priority species has always been a scarce moth in Lancashire and was first recorded around 1900 at Crosby, near Liverpool. It was not until 1918 that another site for this species was found, when a female was reported from Longton Marsh, near Preston. These remained the only Lancashire locations until the 1960s and 1970s, when the moth was reported from several coastal sites near Lytham, Blackpool and Sunderland Point. Of these, only Sunderland Point still retains a colony, the other areas having been developed upon or have been the subject of unsuitable land management.
The series of records of Belted Beauty from the Sunderland Point area started in July 1975 when Pat Livermore found a larva during part of a botanical survey of north Lancashire. The next report came some seven years later when John Leedall came across a male in the same area in April 1982. This and the previous report prompted Dr Ian Wallace to search the site on 27th June 1993 when he and his wife found one larva. All these sightings suggested that the moth was just about hanging on but the extremely small area of apparently suitable habitat was very worrying. During 2001, Alice Kimpton carried out a survey of northwest England, sponsored by Butterfly Conservation, to look for suitable areas for, and signs of colonies of the moth. However, due to Foot and Mouth (FMD) restrictions it was not possible for her to visit the Sunderland Point area and another year went by with no confirmation of whether the colony still survived.
As part of the Lancashire Moth Group’s efforts to survey for scarce moth species in Lancashire, a search was organised for the Belted Beauty on 6th April 2002 at Potts Corner, south of Heysham Power Station. Butterfly Conservation was contacted and sponsored the event by paying for Dr. Paul Waring, the organiser of research into scarce moths in Britain, to attend. Alice Kimpton was also invited due to her knowledge of this species on the Wirral, the only known English colony at that time.
In Britain, the moth has always been considered a species restricted of herb-rich areas of coastal sandy grassland. However the search in 2002 proved that its habitat range also included a type of saltmarsh designated by the prevalence of saltmarsh rush (Juncus gerardii) and autumn hawk-bit (Scorzoneroides autumnalis).
The female is wingless and is therefore restricted in its ability to move any great distance. The males rest during the day in relatively open situations and are easy to locate. The green eggs are laid in low lying vegetation (particularly in old seed-heads of sea rush Juncus maritimus) and crevices and cracks in any suitable material, including old fence posts, and can survive tidal inundation. The resultant larvae feed on a wide variety of herbaceous plants growing in the marsh.
The belted beauty is readily surveyed by daytime searches for larvae or the adult moths. In Lancashire the adults are monitored annually during the main emergence period (late March to mid-May) on a series of transects and also by a single organised count with as many participants as possible. There have been noticeable peaks and troughs in numbers from year to year and the moth appears to have a staggered emergence during their long flight period. The largest count came in 2010 when over 1600 moths were found on a single day. In contrast, only a few years later, the organised count struggled to find double figures despite many participants.
Threats to the Belted Beauty in this area come from various sources, such as industrial development and amenity use; longer term predicted sea level rises may be another significant factor. The surrounding raised farmland and sea defences provide no room for expansion of the habitat. Low density cattle-grazing has taken place on the marsh for many years and may be beneficial in keeping some plant growth under control. The involvement of local residents and naturalists in the survey work plus the interest of the farmer who grazes his cattle on the marsh have proved invaluable. This collaborative effort of many individuals has demonstrated what can be done at a local level with minimal resources to establish base-line data, organise continuing surveys and hopefully enable the continued survival of one of Lancashire’s and England’s rarer moths.
Howe, M.A, Hinde, D., Bennett, D. and Palmer, S. (2004). The conservation of the belted beaty Lycia zonaria britannica (Lepidoptera, Geometridae) in the United Kingdom. Journal of Insect Conservation 8: 159-166, 2004.
Kimpton, A. 2000. A report on possible sites for the Belted Beauty Moth (Lycia zonaria britannica Harrison) in the North West of England. Butterfly Conservation, Wareham. (Butterfly Conservation report No. S00-18).
Kimpton, A. 2002. Survey for the Belted Beauty moth (Lycia zonaria britannica Harrison) in the North West of England: April to June, 2001. Butterfly Conservation, Wareham. (Butterfly Conservation report No. S02-04).
Lawson, K. 2011. A study of the habitat requirements of the belted beauty moth, Lycia zonaria britannica at Potts Corner, Middleton, Morecambe Bay 2010 – 2011. Lancaster University & Blackpool & The Fylde College.
Parsons, M.S., 2001. The European Status of the UK Biodiversity Action Plan moths. Entomologist’s Record & Journal of Variation, 113: 49-62.