The ecology, conservation and population genetics of three species of Zygaenid moths, Zygaena lonicerae, Zygaena purpuralis and Zygaena filipendulae in North West Scotland
This study investigated the ecology of three species of Zygaenid or Burnet moth, the Narrow bordered five spot burnet or Talisker burnet (Zygaena lonicerae jocelynae) a sub-species confined to three locations on the Isle of Skye, the Transparent burnet (Zygaena purpuralis) restricted to between 25 and 30 'colonies' on the west coast of Scotland (also described as a sub-species) and the Six spot burnet (Zygaena filipendulae), which although common is restricted to coastal areas in Scotland. The burnets of Scotland have been the subject of some conservation concern given their limited distributions in Britain and the discovery that the New Forest burnet colony in Argyll was under severe pressure from an increase in sheep grazing. This concern has focused attention on the other restricted burnets. All three species occur at Talisker, Isle of Skye, where autecological studies of the species were undertaken. This data could then be examined in terms of the requirements of the three species. Grazing levels are crucial to the ecology of all three of the species and it is the variation in the vegetation structure occurring at each specific area within Talisker which allows the three species to co-occur there. The Talisker burnet is restricted to ungrazed undercliff grassland where its foodplant, Lathyrus pratensis grows in abundance. Within the ungrazed areas there is considerable variation in the vegetation heights available and in areas were the vegetation is short the larvae are found relatively high in the vegetation, as are the pupae of this species. Genetic analysis of populations of Z. purpuralis indicate that they are quite diverse, having maintained a high rate of genetic variability between populations which are relatively close and indicates that populations greater than 10 kilometres apart have very little interchange. To conservation population of Z. purpuralis grazing is required on several Z. purpuralis sites to maintain the short vegetation required, while at Talisker Z. lonicerae requires early successful areas which are created by natural rockfalls and soil slippage.