The dynamics the flight of the imago of the fritillary Clossiana freija (Insect, Lepidoptera, Nymphalidae) and the number of its local populations in the middle taiga landscape (on the example of the Kivach Nature Reserve)

The dynamics of the flight of the imago of the pearl butterfly C. freija was studied based on the materials of field experiments with labeled butterflies. The research was performed in the Kivach Nature Reserve (Republic of Karelia) in 1996 and 2016. The species population in the study area is organized according to the type of metapopulation, the spatial structure of which is formed by three local populations (subpopulations). To calculate the demographic parameters of these populations, the stochastic Jolly–Seber model was used, and the absolute number was estimated by the Poisson distribution. The maximum size of the largest local population was about three hundred imagos. The butterfly flight begins in the last decade of May and lasts about three weeks. Sexual differentiation consisted in the emergence of males earlier, by 4-5 days – their density by the time of the emergence of females was approaching the maximum values. The model estimate of the daily replenishment of subpopulations due to the birth and immigration of butterflies averaged about one third of their total number. The interval between the first and the last catches of an individual was on average 2–3 days, with a maximum value of 8 days. The time of the presence of an individual in the habitat calculated on the basis of the model reached 12 days. The sex ratio in the local populations varied from equality to a fourfold predominance of males. The asynchrony of the course of the population curves in local populations indicates the autonomy of the demographic processes occurring in them. In the conditions of the nature reserve, the cause of the degradation of the existing population system may be a steady decline in the quality of habitats due to weather changes associated with global warming.