Intranuclear dynamics of chromosome 6 in nurse cell nuclei of Calliphora erythrocephala Mg. (Diptera: Calliphoridae) was studied. The 3D FISH method was used for the first time to study chromosome territories in highly polyploid nuclei whose chromosomes undergo morphological changes. A considerable change in the intranuclear location of chromosome 6 and a morphological alteration of the chromosome territory in the course of chromatin polytenization were revealed.