Influence de l'âge parental sur la dimension des œufs, la durée de développement, et la taille thoracique des descendants, chez Drosophila melanogaster

The successive daily batches of a population of Drosophila melanogaster were analysed for a period of 3 weeks. Variables considered were: duration of embryonic development from egg laying to hatching of the larva, total duration of development from egg laying to emergence of the adult, egg length, and adult thoracic size. The interrelationships among these variables were considered first within each individual age group and then within the pooled progeny. Both egg length and duration of embryonic development showed the same pattern of variation with parental age: they increased up to a maximum corresponding to the tenth to the fourteenth day, then they decreased up to the end of the observation period. On the other hand, total duration of development varied cyclically with parental age: it decreased up to a minimum corresponding to the fifth to seventh day, then it increased up to the twelfth to thirteenth day, and finally it decreased again up to the last day of observation. Variations of thoracic size are statistically less significant. A negative correlation exists between thoracic size and duration of development, and this both in each daily batch and within the pooled progeny.