Population ecology of the apollo butterfly Parnassius Apollo in the Austrian Alps – a mark-release recapture study

Abstract

Environmental changes affect the dynamics and behaviour of organisms, especially in the European Alps. Thus, studies on the population dynamics and phenology of organisms provide valuable insights on the population ecology. The Apollo butterfly, Parnassius apollo, is a flagship in insect conservation and an excellent model species to conduct population ecology studies. We assessed the population ecology of this endangered butterfly species using mark-release-recapture in the northern Alps. Based on these data, we estimated population size and structure, demography and phenology, and the dispersal of the species. The estimated population size consisted of 480 individuals, with 308 males and 172 females, i.e. the demographic structure had a male-biased sex ratio. Most individuals caught were undamaged, but the proportion of aged individuals increased over time. Mean altitude of observations was shifting up-hill with time, in mean 2.3 m per day. Individuals´ dispersal embraced the entire study area and thus dispersal was comparatively high. The strong assumed dispersal of the species should ensure that individuals are in active exchange among local populations. This should also ensure the recolonization of empty habitats. However, although being high for P. apollo, the overall population density was lower than for many other butterfly species so that the number of individuals available for connecting populations is limited.