The diploma thesis is focused on finding out the influence of the ground squirrel (Spermophilus citellus) on the colony of the rebel bluebird (Phengaris rebeli). The area of interest in which the diploma thesis was carried out is located in the Muránska planina National Park in the Biele vody locality. The research was conducted in the months of June - July, during one season. The ground squirrel population is found here on xerothermic meadows and pastures, where the management is donkey grazing, cattle grazing, manual or machine mowing. This management has a positive effect on the growth of the nutrient plant of this butterfly, which is Gentiana cruciata. The research was done by the method of counting eggs on a nutrient plant and by counting gentian plants. The area was divided into 16 localities. A total of 2404 gentian and 1265 eggs were recorded here. Most eggs on the plant were found on the upper leaves.