Wing patterning in faster developing Drosophila is associated with high ecdysone titer and wingless expression

‘Developmental robustness’ is the ability of biological systems to maintain a stable phenotype despite genetic, environmental or physiological perturbations. In holometabolous insects, accurate patterning and development is guaranteed by alignment of final gene expression patterns in tissues at specific developmental stage such as molting and pupariation, irrespective of individual rate of development. In the present study, we used faster developing Drosophila melanogaster populations that show reduction of ~22% in egg to adult development time. Flies from the faster developing population exhibit phenotype constancy, although significantly small in size. The reduction in development time in faster developing flies is possibly due to coordination between higher ecdysteroid release and higher expression of developmental genes. The two together might be ensuring appropriate pattern formation and early exit at each development stage in the populations selected for faster pre-adult development compared to their ancestral controls. We report that apart from plasticity in the rate of pattern progression, alteration in the level of gene expression may be responsible for pattern integrity even under reduced development time. • Drosophila melanogaster populations selected for faster development emerge as functional adults in just 7 and half days. • The selected flies are significantly smaller than control flies, yet show no phenotypic abnormalities. • Small yet normal phenotype suggests normal tissue and organ patterning. • Increased ecdysone levels during entire third larval instar ensures completion of stage specific growth within the available short time. • Pattern stability may be maintained by higher intensity of Wg and downstream Ac and Ct in wing imaginal discs.