During cell division, centriole duplication has to be tightly regulated to ensure that chromosomes are accurately segregated. Disengagement of parent centrioles is thought to represent the licensing event to ensure that centriole duplication occurs exactly once during the cell cycle, but the exact mechanisms are not fully understood. In this work (p. 3434), Giuliano Callaini and colleagues explore centriole duplication in spermatocytes of the butterfly Pieris brassicae. These cells have two centriole pairs that represent the platform for the assembly of four long cilium-like projections, which – unlike in most animal cells – persist during spermatogenesis and spermatid differentiation. Interestingly, the authors observe that procentrioles begin to assemble during prophase of the first meiosis when parent centrioles are still engaged. These procentrioles, however, do not fully mature because their size does not change during meiotic divisions, whereas their number increases. The authors are able to determine that the failure to assemble the full set of centriolar microtubules is the factor that prevents centriolar maturation; these procentrioles are therefore unable to function as a template for centriole organisation. Thus, this work not only provides the first evidence for an exception to the view that centriole disengagement licenses centriole duplication but also highlights this system as a unique model in which to analyse different steps of procentriole formation in detail.