CROATIAN FAUNA – BUTTERFLIES, marsh fritillary

Marsh fritillary Euphydryas aurinia Marsh fritillary (Euphydryas aurinia) is one of the most recognizable species from the brush-footed butterflies family (Nymphalidae). It was named after the type of habitat in which it most often resides, namely wet meadows. Two ecological types of this species are known in Croatia - populations inhabiting the wet grasslands of the continental region and populations inhabiting the dry grasslands of the Alpine and Mediterranean regions of Croatia. In the continental region, its populations are usually isolated with fragmented suitable habitats. The destruction of such smaller wetlands and changes in the water regime represent the most pronounced threat to the continental region, which can lead to the local extinction of the species. In the Alpine and Mediterranean regions, the species' populations are more numerous and present on larger pastures and grasslands, where succession caused by the reduction of extensive grazing poses the main threat. Recent research has confirmed the presence of the species in almost all historically known areas and numerous new localities in all regions of Croatia, with numerous populations throughout the Dalmatian hinterland. The marsh fritillary lives in wet limestone open meadows with feeding plants from the genera of pincushions (Scabiosa), widow flowers (Knautia), knapweeds (Centaurea), honeysuckles (Lonicera), Plantago, Teucrium, as well as devil's-bit (Succisa pratensis). Host plants of its caterpillar include the great yellow gentian (Gentiana lutea), the common honeysuckle (Lonicera periclymenum), the dwarf pincushion flower (Scabiosa columbaria) etc. Females choose larger, more prominent host plants or smaller areas with lower vegetation where host plants grow in great abundance. Females lay up to 350 round yellow eggs in piles on the underside of leaves, and, at the end of July, caterpillars emerge from them. The species' caterpillars have a dark to black ground color and prominent bristles on the body. At the beginning of their development, the caterpillars do not feed individually, but rather colonially and in small silk webs. Starting from September, the marsh fritillary hibernates colonially in the fourth life stage of the caterpillar in winter hibernation webs, its silky shelter. At the end of March of the following year, after hibernation, caterpillars in their fourth life stage stop the "collective" feeding, and so in their fifth and sixth stages they feed individually. From the end of April to the beginning of May, the species lives in the pupal stage, and, in the first or second week of May, depending on the weather conditions, an adult butterfly in its reproductive development phase emerges from it. Marsh fritillaries create one generation per year, and their imago flies from April to July. In Croatia, the marsh fritillary can most often be seen in May and June. The species is threatened by the loss of habitats due to succession, meadow desiccation due to changes in the water regime, or intensification of agricultural production. Parasitoids of the Hymenoptera order also greatly affect the decrease in the number of the fritillary's population. Marsh fritillaries are protected by the Nature Protection Act in the category of strictly protected native wild taxa. The species can be found in Appendix II and IV of the Directive on the conservation of natural habitats and of wild fauna and flora (Council Directive 92/43/EEC), and its preservation is among the preservation goals of 26 areas within the Ecological Network of the Republic of Croatia.