Ábrahám Levente – Farkas Sándor: Butterflies along the river Drava, 2008

Within biodiversity, the greatest proportion of species diversity is made up by invertebrate animals. The number of invertebrate species indicated by nature conservation research pursued during the past two decades along river Drava is around 4000. The actual number of invertebrate organisms, though, is probably much higher, maybe reaching as many as 25 000 species. This huge number of animals indicate dearly the high natural value of the Drava area. One of the most species-rich group of invertebrate animals are butterflies and moths (Eepidoptera). Even in a relatively small area such as the Drava region, their numbers are beyond 2000. The majority of them about 1300 species - are small-bodied moths flying usually at night. However, the largest insect species found in Europe also belongs to the group of moths (e.g. great peacock - Saturnia pyri). According to the traditional division of moths and butterflies, another group is that of larger moths, about 90% of them being nocturnal species. Among larger moths, there are only few diurnal species (butterflies), yet they are the most well-known insects, due to their colourful appearance. The life of a butterfly is usually very short, only seldom exceeding two weeks. The most important stages of their life is mating flight and copulation, ensuring continuity into the next generation. Fertilised females are careful in choosing the particular plant they are to deposit their eggs onto, as this hostplant will serve as food for the hatching caterpillars. The caterpillars of the majority of butterflies are food specialists, feeding on only one or just few plant species. The life of caterpillars is spent almost exclusively with feeding: they can consume green foliage matter as much as their own weight each day. Accordingly, they develop fast, and after a number of moults (replacement of old larval integument) they will eventually pupate. The pupae of butterflies are normally hung upside down on plant stems or tree trunks where they remain motionless. Although butterflies appear dormant in a their pupa stage, in fact this is the time when there are the greatest changes during the life of a butterfly: the caterpillar develops into a magnificently coloured butterfly. Butterflies are quite variable in colour. In most cases, different species can be easily identified based on the patterns of their wings, which are actually formed by the arrangement of tiny chitinous platelets. This small brochure intends to provide information about the habitats of butterflies living along river Drava, and guidance for visual species identification.