Genetica 101: 59–66, 1997. 59 c 1997 Kluwer Academic Publishers. Printed in the Netherlands. Allozyme variation in Parnassius mnemosyne (L.) (Lepidoptera) populations in North-East Hungary: variation within a subspecies group Emese Megl´ ecz 1 , Katalin Pecsenye 1 , L´ aszl´ o Peregovits 2 & Zolt´ an Varga 1 1 Department of Evolutionary Zoology and Human Biology, Kossuth Lajos University, Debrecen H-4010, Egyetem t´ er 1., Hungary; 2 Hungarian Natural History Museum, Department of Zoology, Budapest H-1088, Baross u. 13., Hungary Received 17 September 1996 Accepted 15 April 1997 Key words: allozyme frequencies, genetic drift, heterozygote deficiency, Lepidoptera, Parnassius mnemosyne Abstract Allozyme polymorphism was studied in 11 Parnassius mnemosyne (Linnaeus, 1758) populations in North-East Hungary. Significant departures from Hardy-Weinberg equilibrium were observed in several cases due to heterozy- gote deficiency. Genetic variability did not display geographical pattern; the level of genetic differentiation was similar between adjacent populations and between populations originating from different geographical regions. Even a completely isolated population was not differentiated markedly from the others. Thus, genetic drift can be expected as the main evolutionary force acting in the populations. Introduction Conservation of biological diversity at different levels is an increasingly important task in the face of mas- sive destruction and fragmentation of natural habitats (Soul´ e, 1986). To develop a proper conservation strat- egy for a particular species, it is important to have information both on the genetic diversity and on the ecological characteristics of the species in question. The main goal of this study was to investigate genet- ic diversity in populations of the butterfly Parnassius mnemosyne (Linnaeus, 1758), which is highly endan- gered in Northern and Central Europe (Heath, 1981) and included in the list of the Bern Convention on the protected species. In Hungary, this species still occurs in strong populations. Nevertheless, several popula- tions are isolated and at least potentially threatened, hence the species is protected and included in the Red Data Book of Hungary (Rakonczay, 1990). The inves- tigated populations (Figure 1) originated from the mar- ginal area of the distribution of the P. mnemosyne ari- ovistus (Fruhstorfer, 1907) subspecies group, which is widely distributed in the Northern Carpathians (Zelny, 1956; Varga, 1993). Parnassius mnemosyne is a specialized K- strategist; females can mate only once and they lay about 50 eggs dispersed over a large area (Weide- man, 1986). This species requires structured habitats; larvae feed on Corydalis cava and C. solida, which occur in humid, deciduous forests, while imagoes pre- fer clearings for mating and feeding. After the last glacial period, the investigated area was continuously covered with forest until the appearance of Neolithic culture approximately 6000 years ago (Willis et al., 1997). As a consequence of human activities, exten- sive deforestation occurred in the valleys, resulting in the separation of the forested area of the Aggtelek karst (Figure 1: pops. 1–2), B¨ ukk mountains (Figure 1: pops. 3–10), and the hardwood gallery forests of the Tisza region (Figure 1: pop. 11). The largest continuous woodland in northeast Hungary remained on the B¨ ukk plateau (Figure 1: pops. 3, 4, 8, 9) until recent clear- fellings approximately 200 years ago. Concurrently, the extreme fragmentation of gallery forests due to the control of Tisza river and its tributaries (i.e., altering the river bed by cutting of its curves) resulted in the isolation of the Saj´ ol´ ad forest (Figure 1: pop. 11). The aim of our work was to answer the follow- ing questions: Does genetic substructuring exist in the