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Suffolk Natural History, Vol. 33 T H E Q U E E N O F SPAIN F R I T I L L A R Y ARGYNNIS LATHONIA L. 1758 AT M I N S M E R E R S P B R E S E R V E , S U F F O L K . C. ANDERSON AND R. WILSON
Introduction The Queen of Spain Fritillary is a rare butterfly in Suffolk. The only acceptable records this Century prior to 1995 are an individual sighted at Battisford in August 1900 (Mendel and Piotrowski, 1986) and an individual feeding on buddleia Buddleia davidii Franchet at Gorleston on Sea in 1991 (Stewart, 1996). This fritillary has been documented as probably breeding in Britain once, during the summer of 1945 in Cornwall, thus producing a second brood. No specimens were recorded the following spring (Emmet and Heath, 1989). During 1995 and 1996, this fritillary was seen at Minsniere. Distribution and Biology Higgins and Riley (1993) describe the ränge of this species as being from western Europe, north Africa and the Canary Islands and across central Asia to the Himalayas and western China. The food plant of this species is typical of the family, being any member of the violet family, Violaceae. The butterfly is a notable migrant and is said to hibernate as an egg, larva or imago according to local conditions (Higgins and Riley, 1993). Carter and Hargreaves (1994) State that the Queen of Spain Fritillary has two, or occasionally three, broods per year. Eggs are laid on the food plant in August (second brood) and hatch in about a week. The Caterpillar takes roughly one month to become fully grown. The flight period can Start in February and continue into November. The Queen of Spain Fritillary at Minsniere, 1995-1996 In 1995, a Queen of Spain Fritillary was observed on a warden's buddleia bush at approximately 16:30 on 6 August (Anderson, 1995). It was observed by a few people before flying off. This was the first observed individual to be seen in Suffolk since 1991 and the first record of this species for the reserve. The second record for this species occurred in somewhat unusual circumstances in that it was found dead in a pitfall trap located on the heathland and is documented in Wilson (1995). The conclusion from these records is that these were migrants and it was thought at the time that this was probably a one-off event. In 1996, there was a large influx of the Painted Lady Cynthia cardui L. 1758 along the east coast, where numbers in excess of 100 individuals were seen in some places. On 10 July, a small fritillary was reported flitting along a woodland bridleway on the reserve. However, the views obtained were not good enough to assign it to a species and the record remains unconfirmed. Fritillaries are rare in Suffolk and especially so at Minsmere, the only species recorded recently at Minsmere is the Queen of Spain. The next record was on the same buddleia bush as in 1995. An individual was observed on 31 July nectaring. However, this was not the last record. The majority of the records feil between 17 August and 16 September when
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up to six individuals were present at any one time. They were all located within a small area of rough ground in the northern half of the reserve. The first record consisted of two individuals, noted on a guided walk led by the Senior Warden, Ian Robinson. These were observed sunning themselves on an area of sandy ground on the heath. The following day, four individuals were observed in the same locality. The next few days resulted in almost total coverage of the site as a result of informing the general public and giving guided walks to show them the butterflies. On 22 August, five individuals were noted in three localities, two on an arable field and three on heathland rides. The highest count was of six on 26 August. As in 1995, a Queen of Spain was collected in a pitfall trap on the heath between 12-26 August. On 29 August, over 80mm (3 inches) of rain feil and it was assumed that this would have killed off any surviving individuals. However, on 31 August, two individuals were observed in separate arable fields. On 1 September, one individual was observed. A gap of three days passed when no one went to see them, but on 5 September, four individuals were observed in an arable field. On 7 September four individuals were observed in three different localities, one on a bridleway, one in an arable field and two on a ride. Following these observations, numbers dwindled to 1-3 and the last confirmed sighting was of two individuals, one frayed and one quite fresh, on the 16 September. Behaviour of Individuals All records of behaviour relate to individuals seen from 22 August onwards. The butterflies were generally observed from approximately 11:00 to 15:30 (Radford, pers comm). DĂźring the first few days, the butterflies were observed sunning themselves in warm, sheltered areas on the ground where the Vegetation was very short due to heavy grazing by rabbits. When a fritillary approached another individual sunning itself, the 'resident' would fly up and chase off the intruder in a characteristic spiralling flight which was interpreted as territorial behaviour. This behaviour was noted on several occasions. Towards the end of the period. the butterflies were noted flying in arable fields. On close inspection, it was noted that there were large numbers of field pansy Viola arvensis Murray. This is a potential food plant as it is a member of the violet family. Although no observations were made of ovipositing, two indirect factors suggest that the butterflies were breeding. The evidence is as follows: 1. Over a period of 23 days, a continuous record of Queen of Spain Fritillaries was noted. These were not all the same ones as during this period, fresh individuals were noted. This suggests that they had hatched out within a few days of being observed. 2. With the exception of Carlton Marshes, Minsmere was the only locality on the east coast of Britain where Queen of Spain Fritillaries were recorded in 1996. This would be unusual if continuous migration from the continent was occurring and suggests that the fresh individuals were bred locally. Conclusions Over a period of six weeks, Queen of Spain Fritillaries were recorded at Minsmere RSPB Reserve, but the majority of records were noted in a 31 day
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period between 17 August and 16 September. Indirect evidence suggests that they bred on the reserve or adjacent to the reserve. A food plant, field pansy is present in large numbers where the butterflies were observed. Although no individuals were seen to oviposit on these plants, the gap between the first record (July) and the flight period in August and September coincides with the known length of time for the larval stage to mature. In our opinion, during 1996 a few individuals (gravid females/females and males) arrived on the east coast at or near Minsmere. The isolated July record may represent this scenario. This 'pioneer' then discovered suitable breeding habitat and laid eggs on the field pansies in nearby the arable fields. This resulted in a brood which hatched out intermittently in the 31 day period when several individuals in varying states of freshness were noted. Acknowledgements The authors would like thank Doug Radford and Geoff Welch for comments regarding the production of this paper. References Anderson, C. (Co-ordinator). (1995). Butterfly records at Minsmere, 1995. (Unpublished). Carter, D J . and Hargreaves, B. (1994). Collins Field Guide: Caterpillars of Britain and Europe. Collins: London. Emmet, A.M. and Heath, J. (1989). The Moths and butterflies ofGreat Britain and Ireland, Volume 7, part 1: Hesperiidae-Nymphalidae. Harley Books: Colchester. Higgins, L.G. and Riley, N.D. (1993). Collins Field Guide: Butterflies of Britain and Europe. Collins: London. Mendel, H. and Piotrowski, S.H. (1986). The butterflies of Suffolk. Ipswich Suffolk Naturalists' Society, Ipswich. Stewart, R.G. (1996). 1995 - A record year for rare butterflies in Suffolk. Trans Suffolk Nat. Soc., 32: 6-16. Wilson, R.I. (1995). Report on the invertebrates of Minsmere RSPB Reserve. (Unpublished). Richard Wilson Charlotte Anderson Reserves Ecology, Minsmere RSPB Reserve, RSPB, Westleton, Stalham House, Saxmundham, 65 Thorpe Road, Suffolk, Norwich, IP17 2BY Norfolk, NR11UD
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