The violet copper (Lycaena helle) is one of the most endangered butterflies in Europe, with a population pattern of steady decline despite consevation efforts. The main threat to the species is believed to be habitat fragmentation and loss due to changes in land use practices. In order to direct conservation efforts toward the areas where they make the most difference, we need to better understand the ecological needs of the species, on both local and meta population levels. Since habitat quality is a crucial factor for succesful reproduction, increased knowledge of the species’ habitat requirements is of utmost importance. In this study, I investigated whether there is a correlation between the share of hatched eggs and leaf size and shape of the host plant Bistorta vivipara, which vary greatly depending on the level of solar exposure. In the summer of 2022, I searched for eggs and larvae of L. helle on leaves of B. vivipara on three rich fens situated in the municipality of Ånge, Västernorrland County. All leaves with eggs and/or larvae were photographed next to a ruler in order to measure length and width, and the total number of eggs as well as the number of hatched eggs were documented. I then divided the leaves into four classes based on the length/width ratio. Chi-square tests were conducted on the share of hatched eggs per leaf class and locality. The results showed a tendency for a larger share of hatched eggs than expected in leaf class 2, and a smaller share of hatched eggs than expected in leaf class 3, but the results were non-significant. Similarly, the results showed a tendency of a larger share of hatched eggs than expected on locality 2, and slightly smaller shares of hatched eggs on localities 1 and 3, but these too were non-significant. In conclusion, more studies are needed in order to better understand how we can conserve this threatened species.

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.