Three species of burnet moths (Zygaena filipendulae, Zygaena lonicerae and Zygaena viciae) were studied on the Baltic island Öland, Sweden, in order to reveal the habitat requirements of different life stages.
Larvae were found among a higher cover of their most important host plant, Lotus corniculatus, Trifolium medium/pratense or Vicia spp., than were pupae or imagines, and were also observed on plants larger than randomly examined plants. Imagines actively selected nectar plants of Centaurea and Cirsium, growing in sunny conditions, but other red and violet composite flowers were also favoured.
Pupae of Z. filipendulae were found in taller vegetation than were larvae and imagines, probably because the cocoons are spun high on stems of grasses and other plants. The chance of finding such suitable substrates rises with increasing vegetation height.
A large scale analysis of occupancy patterns was also made, evaluating the relationship between burnet presence or absence and the area of meadows and pastures within 10 x 10 km grid cells in southern Sweden. All three species showed a positive relationship with increasing area of semi-natural grassland. Thresholds for the amount of habitat, below which the likelihood of occurrence declined more rapidly, could be distinguished around a 40-50 % probability of occurrence.
Conservational work should aim at preserving and restoring open and sunny areas rich in the respective host plants and nectar sources, but vegetation management must be executed with great care or late in the season to not harm unhatched pupae and to maintain substrates suitable for Z. filipendulae pupation.
Responsible for this page: Agneta Johansson
Last updated: 05/11/09