Population structure, behaviour and selection of oviposition sites of an endangered butterfly, Parnassius mnemosyne, in Litovelske Pomoravi, Czech Republic

A population of Parnassius mnemosyne L., an endangered buttery species, was studied for two seasons by mark-release-recapture (MRR) techniques in the Litovelske Pomorav Protected Landscape Area, Czech Republic. There were four distinct colonies in the area; the MRR data indicate that the largest colony contained over 1000 adult males during peak ight in 1996 suggesting that the area harbours one of the largest populations of the species in the Czech Republic. The detected rate of intercolony movements showed that the individual colonies were not genetically isolated, but the interchange of individuals was limited. Capture sex ratio and estimated sex ratios were both consistently male-biased. We suggest that this might be caused by different behaviour of the sexes which renders the males more catchable: the females spent most of their time either egg laying or resting, which makes them inconspicuous compared to the patrolling males. Preferred oviposition sites were open, sunny patches such as forest clearings which may be due to different hostplant quality compared to hostplants under closed canopy. The heliophily of the species and the dependency of females on open oviposition sites render the buttery vulnerable due to a decline in coppice management and replacement of ne mosaic of sunny and shady patches by even-aged forest stands.