Den violetta guldvingens (Lycaena helle) äggläggningsplatser : - En fältstudie i Norrbottens kustlandskap

Sammanfattning: The violet copper (Lycaena helle) is one of Europe’s most endangered butterflies as a result of loss and fragmentation of its habitat. In order to further understand the habitat requirements of this species it is important to observe the specific characteristics of the oviposition sites. There is little research on L. helle in Sweden and the least in the northern parts. In this study I searched for eggs and larvae along a seashore meadow in Norrbotten County where a substantial number of L. helle recently had been found. The area differed from the species’ usual habitat in that the host plant Bistorta vivipara was scarce in large parts. The coastline was split into two areas for comparison according to vegetation type and direction of the shore, one seemingly more suitable for L. helle and the other less so. The results showed that oviposition sites had a lower coverage of, and average height, of the surrounding vegetation than potential oviposition sites without eggs. The coverage of the host plant did not differ between oviposition sites and sites without eggs. Most of the eggs were found on the first area where, surprisingly, a few Bistorta vivipara had up to eight eggs on a single leaf. The sometimes complete lack of eggs on the second area, while still containing a reasonable amount of Bistorta vivipara, confirms that the presence of the host plant is not enough for the females to lay eggs and that any host plant will not be chosen as an oviposition site. The amount of eggs found in the first area together with its structure and east-facing shore further confirms that this species is dependent on lower and more sparse vegetation together with high solar radiation.