The behaviour of ciliate nuclei.
Starvation induces cyst formation or cell mating.
Only one macronucleus and one micronucleus are retained in a cyst. A diploid micronucleus is formed by the fusion of two haploid micronuclei. The new diploid micronucleus divides mitotically and one of them develops into a new macronucleus. The remaining new diploid micronucleus divides again to give two micronuclei. At the end of development, the macronucleus divides so that the nuclear complement of two macronuclei and two micronuclei is reconstituted.