The number of nuclei in the nurse chamber and the frequency distribution of nurse chambers with different numbers of nuclei in seven different species of non-paedogenetic gall midges of the subfamily Cecidomyiinae were analyzed. No evidence was found to indicate that the egg follicles with a low number of nurse nuclei undergo a selective degeneration in the ovarian development of non-paedogenetic gall midges. It is known that the multinucleate nurse chamber in Cecidomyiidae develops by the fusion of a variable number of somatic cells with the germ-line-derived nurse cell. This situation is interpreted by us as an unusual oogenetic strategy for increasing the number of rDNA templates available for transcription, which evolved in the insect group extremely poor in ribosomal RNA genes.