THE ECOLOGY OF THE CHEQUERED SKIPPER BUTTERFLY CARTEROCEPHALUS PALAEMON IN SCOTLAND .1. MICROHABITAT

1. The microhabitat of adults and larvae of the butterfly C. palaemon was studied by comparing their microdistributions with the variety of vegetation present within a study site. 2. The vegetation of the study area was described and mapped: four communities were readily identified in the field and a further eight were classified by ordination techniques. Most communities were peaty bogs and mires dominated by the foodplant of C. palaemon, purple moor-grass Molinia caerulea. 3. Adult males and females, and larvae, occurred at low densities and had separate microhabitats. 4. Males were confined to areas of sparse vegetation on drier ground in bays in the woodland edge, selected to aid mate location. Females spent most of their time feeding and their microdistribution was correlated with discrete patches of favoured nectar plants. The larval foodplant was sparse in all adult microhabitats. 5. Larvae were found in more widespread microhabitats where the foodplant grew in association with Myrica gale, Betula pubescens or Pteridium aquilinum. Larval microhabitats occurred on slopes in the zone between drier soils of the woodland edge and waterlogged peats of level ground. M. caerulea was notably more luxuriant in these microhabitats and few larvae were found in nutrient-poor areas characterized by Erica tetralix and Juncus sp. 6. The results are discussed in relation to the availability of suitable microhabitats in western Scotland and it is suggested that the restricted abundance of adult resources limits population distribution. Large areas of continuous and varied semi-natural habitat are required to support both adults and larvae. The implications for management and the extinction of a population of C. palaemon in England earlier this century are discussed.