The influence of larval crowding on the development time of populations of Drosophila melanogaster on chemically defined medium

Abstract

Work with Drosophila melanogaster, cultured on chemically defined amino acid medium, showed that at extreme larval densities the average time to pupation and eclosion of the survivors of the insect population is a decreasing function of the initial density. Evidence is presented which illustrates that at extreme densities larval development rate is significantly increased. Possible causes of this phenomenon are cited. It is stressed, however, that a very complex situation exists and more experimentation, particularly biochemical analysis, will be necessary to arrive at the proper causative factors. A new formula is presented for a chemically defined medium for Drosophila melanogaster, and detailed methods of preparation given. The new formula will support an estimated 200 larvae through complete development to adult flies on 5 ml of medium. It is thought that the system utilizing the development of Drosophila melanogaster on chemically defined amino acid medium is a fundamental one for the experimental analysis of developing insect populations.