Conserving the Barberry Carpet moth in Suffolk

CONSERVING THE BARBERRY CARPET MOTH IN S U F F O L K P.

WARING

The Barberry Carpet moth, Pareulype berberata Schiff., is an endangered species in Britain (Shirt, 1987). It is protected by law under the terms of the Wildlife and Countryside Act, 1981, Schedule 5, which makes it an offence to collect or trade in the eggs, caterpillars, pupae or adult moths, without a licence. The caterpillars of the moth feed on Wild Barberry, Berberis vulgaris L. For the last 18 years the only known breeding ground for the moth has been a Single site in west Suffolk. In recent years the site has been managed with the conservation of the moth in mind. This has involved a working partnership between the private landowners, the local Borough Council, the Suffolk Wildlife Trust, the Suffolk Naturalists' Society and the Nature Conservancy Council. The site presently contains about 120m 1 of Berberis, growing with blackthorn, elm and other species in two hedgerows.

Historical Background The Suffolk colony of moths has a long recorded history extending back at least to the 1860s, when it was discovered by Skepper (Morley, 1937). In the late 1960s and early 1970s the site was threatened with destruction by proposed roadworks. In response to this threat the late Charles Pierce and his colleagues reared the moth in captivity and attempted to establish a new colony on some ground which they planted with Berberis for the purpose.

Pierce has recorded the details in earlier volumes of these Transactions.

There were practical difficulties both in rearing the moth in the quantities required for the founding of a new colony and in the preparation of the site to receive them. There was insufficient time to allow the young Berberis plants to grow and this was probably the major factor that led to the ultimate failure to establish the moth. In addition there was a fire which destroyed some of the young plants. Pierce released his stock at another site which had a Single well-established bush of native Berberis vulgaris but the success of this release in founding a new colony is not recorded.

In the meantime the route of the proposed roadworks was modified and the original colony was spared for the time being. However, only a short while later several of the largest Berberis bushes were destroyed during minor roadworks at one end of the colony (R. Eley, pers. comm.). Then, c. 1983, street lights were installed which light up the area. Fortunately these are of the yellow sodium type which do not seem to be particularly attractive to moths. In the late summer of 1983 some of the surviving Berberis bushes were scorched when vandals set fire to some bales of straw that were stacked near the hedgerow (E. Milne-Redhead, pers. comm.).

In 1985 the location of the colony was declared a site of special scientific interest (SSSI) by the Nature Conservancy Council (NCC). As a result of this

Trans. Suffolk Nat. Soc. 25

38

Suffolk Natural History, Vol. 25

designation NCC must be notified in advance of any proposals for further developments or changes of management that may interfere with the moths or any other aspects of the scientific interest of the site. Since then the hedgerows have been sensitively managed to encourage the Berberis and to reduce crowding from competing species. The Suffolk Wildlife Trust have organised selective pruning of the Berberis on rotation. The Borough Council have attended to the remainder of both hedgerows. In 1986 further roadworks were proposed which would result in the loss of a length of 9m from the middle of one of the hedgerows. This section of hedge contained no Berberis and after considering the matter NCC issued consent for the work to proceed. The work was carried out during last winter (1988/89). The intention is that some young Berberis will be planted near the gap to restore the protection from the wind and to provide the moth with additional food-plant.

Present Conservation Efforts In 1987 the post of moth specialist was created within the Terrestrial Invertebrate Zoology Branch of NCC, initially as a three year contract. This has enabled me to review the status and conservation of the Barberry Carpet moth in Britain and to augment the continuing efforts of the Suffolk Wildlife Trust and N C C regional Office. As a result of this work I report the following items of information: 1. Suffolk has supplied almost all the specimens of this moth that are preserved in British collections since the discovery of the colony in the 1860s. O n the basis of the collections I have seen, there are several thousand specimens in existence at minimum. These constitute a unique record of the colony over the years. As long as the colony continues, the moths can be compared with related individuals taken on the same site over a hundred years previously and at various times in between. This could be of value to future studies in a variety of biological disciplines, including evolutionary genetics and analysis of biochemical markers.

2. The Suffolk colony of Barberry Carpets is the only one with a long unbroken history. Formerly the Barberry Carpet was widespread in Britain. Jenner-Fust (1868) notes it from a number of regions of England including the Wilts/Dorset area, Essex/Herts/Middx, the Cambs/Hunts/ Northants/Beds area, Hereford/Worcs/Warwickshire, and the Notts/ Derby/Leicestershire region. By the turn of the Century Barrett (1902) reported that the moth had been 'exterminated in some of its localities by the destruction of its foodplant in consequence of the injurious influence which a microscopic fungus growing upon it exerts upon adjacent wheat crops'. It had been discovered that Berberis was host to the wheat rust fungus, Puccinia graminis and this led to the grubbing out of Berberis from hedgerows. This practice of Berberis eradication has continued during the twentieth Century though today strains of wheat are grown which are resistant to the disease and Berberis removal is no longer being advocated.

Since 1900 there have been scattered records of odd individuals of the

Trans. Suffolk Nat. Soc. 25

CONSERVING T H E BARBERRY CARPET MOTH IN SUFFOLK

3.

4.

5.

6.

39

Barberry Carpet moth from such widely separated counties as Devon, Sussex, Lincolnshire and Gloucestershire but outside Suffolk the only known breeding colony in recent years was a small one in Hampshire.

This was damaged by uncontrolled stubble-burning and the last specimens were seen in 1971 (Skinner, 1984; Shirt, 1987).

I visited the Suffolk colony on several occasions in 1987 and 1988. The traditional method of obtaining the moth is to beat the bushes with a stick, over a sheet for the caterpillars and over a net for adults. Use of this method has been largely avoided to minimise disturbance. Consequently the numbers seen have been small - six adults on one visit and three caterpillars on another. Nevertheless the adult moths have been seen at both ends of the site and the density of the larvae may be quite high. All three caterpillars were found within a metre of each other using the beating method at a Single point. The rest of the bushes were left undisturbed but signs of larval feeding by this species were seen elsewhere in the hedge.

The winter pruning of parts of the hedge over the last two years has encouraged some vigorous new growth of the Berberis and the larvae and some of the adults were seen at these parts of the hedge. The Berberis also flowered well in 1988, on a scale apparently unrivalled for years (H. Mendel, pers. comm.).

A new captive stock of Barberry Carpet moth has been developed from one of two females seen in May 1988. She laid over seventy eggs which produced a generation of adults in July and August 1988. From these approximately 1650 eggs have been produced. This stock is providing the basis for a renewed attempt to establish some new colonies to replace those that have been lost through removal and destruction of Berberis.

Several sites with Berberis vulgaris are being intensively surveyed to ascertain whether any Barberry Carpets are present. This has involved both light-trapping for adults and beating for caterpillars. Among these sites are the two at which Pierce released stock. These have been examined on several occasions and no Barberry Carpet have been found.

In contrast both sites support populations of another moth that is dependent on Berberis and that also occurs at the traditional Barberry Carpet colony. This is the Scarce Tissue moth, Rheumaptera cervinalis, which is related to the Barberry Carpet, and its presence indicates that the quantity of Berberis is sufficient to support viable populations of such moths.

The Suffolk Wildlife Trust have managed one of these sites continuously since Pierce's day, in preparation for another attempt at establishment. In 1984 H. Mendal proposed moving some adults from the original colony, but so few were seen that the attempt did not go ahead for fear of jeopardising the main population. It is a great pleasure to report that, provided there are no problems with our captive stock, a trial release will take place during 1989, with follow-up monitoring provided by NCC for 1989/90.

Trans. Suffolk Nat. Soc. 25

40

Suffolk

Natural History,

Vol. 25

Recommendations for the Future 1. All e f f o r t s must be m a d e to maintain the existing colony b e c a u s e of its historical continuity. A d d i t i o n a l Berberis vulgaris should b e planted within t h e SSSI and in t h e vicinity t o replace the bushes that have b e e n lost over t h e years. Berberis vulgaris of native p r o v e n a n c e has b e c o m e difficult to obtain in recent times. All the Berberis stock we have seen u n d e r t h e n a m e B. vulgaris since 1987 has p r o v e d not to r e s e m b l e the wild British f o r m . R e g r e t t a b l y this is t r u e in the case of the small Berberis that w e r e p l a n t e d in the 1980s after t h e roadworks. T h e r e is no evidence that these a r e being used by larvae although they have been present for several years. A b s e n c e of caterpillars m a y be because t h e plants are still less than a m e t r e tall h o w e v e r .

2. T o e n a b l e f u t u r e plantings with native Berberis vulgaris new plants should be p r o p a g a t e d f r o m berries that could be collected f r o m t h e SSSI this a u t u m n , now that the bushes are flowering well. T h e r e is much available space f o r establishing new plants in the vicinity of the existing colony. A p r o p a g a t i o n p r o j e c t should be p a r t of a sustained, long term p r o g r a m m e f o r t h e site. H . M e n d e l informs m e that t h e r e a r e local naturalists Willing to a t t e m p t Berberis p r o p a g a t i o n f r o m native berries.

3. N o m o r e of the original Berberis bushes must be lost f r o m t h e traditional site. T h e quantity of Berberis has already b e e n seriously e r o d e d in recent years. Y o u n g plants are no trade-off for established bushes, at least not in t h e s h o r t t e r m , and this is c o m p o u n d e d by the difficulties of getting suitable stock. It is clear f r o m Pierce's planting in the 1970s that native Berberis vulgaris can t a k e at least a d e c a d e to achieve suitable s t a t u r e . It is slower growing t h a n m a n y of t h e p o p u l ä r cultivars and related Berberis species.

4. E v e n if a p p a r e n t l y successful, t h e efforts to establish new colonies of the B a r b e r r y C a r p e t a r e n o Substitute for the traditional colony. T h e latter has p r o v e n viability for over a Century. T h e o u t c o m e of the establishment trials is at present uncertain. W e may fail f r o m the outset as Pierce did.

E v e n if we succeed in finding a first generation of d e s c e n d e n t s f r o m the stock w e release, we cannot g u a r a n t e e that it will survive in t h e long t e r m .

T h e r e a r e many e x a m p l e s of butterfly introductions that have t a k e n for a few y e a r s and t h e n died o u t . It will be some years b e f o r e we k n o w w h e t h e r or n o t o u r establishments are truly successful. T h e new trials must be seen purely as an a t t e m p t to a u g m e n t the surviving colony. T h e t o p priority must b e to e n s u r e that the traditional colony continues its 130 years of k n o w n history on t h e original site.

5. R e g u l ä r m o n i t o r i n g of t h e original site and any introductions must b e o r g a n i s e d at the local level. T h e search for the B a r b e r r y C a r p e t and t h e m o n i t o r i n g of the k n o w n colony have b e e n extremely e n j o y a b l e for m e .

F o r practical r e a s o n s t h e skills a n d observations that I have m a d e should be passed on to v o l u n t e e r s that a r e based locally for regulär m o n i t o r i n g work f r o m 1990 o n w a r d s . A s t h e species is of national as well as local interest a short s u m m a r y of the results (one page only) should b e issued annually in the national conservation press. This should be c o o r d i n a t e d byNCC. Trans. Suffolk

Nat. Soc. 25

CONSERVING T H E BARBERRY CARPET MOTH IN SUFFOI.K

41

Acknowledgements I would like to t h a n k t h e staff of the Suffolk Biological R e c o r d s C e n t r e , the Suffolk Wildlife Trust and the regional office of the N a t u r e Conservancy Council past a n d p r e s e n t for providing both the archive material a n d the opportunities f o r the continuing conservation of the B a r b e r r y C a r p e t m o t h .

In particular I t h a n k M a r t i n G e o r g e , A n d r e w M o o r e and John Shackles of N C C East A n g l i a n region, H o w a r d M e n d e l and E d g a r M i l n e - R e d h e a d , the contract and m a n - p o w e r services commission staff w h o have carried out the practical w o r k , and t h e B o r o u g h Council and the o w n e r s of each site for their co-operation in m a n a g i n g the sites over recent years. Finally I t h a n k R a f e Eley and G e r r y H a g g e t t w h o a r e currently working to provide the captive stock for t h e a t t e m p t s to establish new colonies. R a f e and G e r r y have spent many h o u r s of their s p a r e time during 1988 feeding and tending caterpillars and m o t h s . It is thanks to their skills and continuing effort that releases can be c o n t e m p l a t e d for 1989.

References Barrett, C. G . (1902). The lepidoptera of the British Isles. 8 , 1 3 8 - 1 4 0 . R e e v e & Co., London.

Fust, H . J e n n e r (1868). O n t h e distribution of lepidoptera in G r e a t Britain and I r e l a n d . Trans. R. ent. Soc. London, Series 3, 4, 417.

Morley, C . ( E d . ) (1937). Memoirs of the Suffolk Naturalists' Society. N o b b s & G o a t e , Beccles.

Pierce, C. W . (1970). B a r b e r r y C a r p e t M o t h . Trans. Suffolk Nat. Soc. 15, 273.

Pierce, C. W . (1971). B a r b e r r y C a r p e t M o t h . Second R e p o r t . Trans. Suffolk Nat. Soc. 15, 511.

Pierce, C . W . (1974). B a r b e r r y C a r p e t M o t h . Third R e p o r t . Trans.

Suffolk Nat. Soc. 16, 316.

Pierce, C . W . (1975). B a r b e r r y C a r p e t M o t h . F o u r t h R e p o r t . Trans. Suffolk Nat. Soc. 17, 394.

Shirt, D . B. ( E d . ) (1987). British red data books. 2. Insects. N a t u r e Conservancy Council, P e t e r b o r o u g h .

Skinner, B. (1984). Colour identification guide to moths of the British Isles.

Viking, M i d d x .

P. W a r i n g , Terrestrial I n v e r t e b r a t e Z o o l o g y B r a n c h , N a t u r e C o n s e r v a n c y Council, Northminster House, Peterborough, PE1 1UA.

Trans. Suffolk

Nat. Soc. 25

Plate 3: Barberry Carpet, Pareulype berberata (p. 37).

- an endangered moth in Britain, still found in West Suffolk (Photo: Paul Waring)

Plate 4: The larva of the Barberry Carpet on Barberry, Berberis vulgaris (p. 37).

(Photo: Paul Waring)