The role of the degradation system of the juvenile hormone in the reproduction of Drosophila under stress

Two natural populations of Drosophila melanogaster were analyzed for the amount of the juvenile hormone (JH) degradation under normal and heat stress conditions. It was found that both populations are polymorphic for this character: the occurrence frequency of individuals with low level of JH hydrolysis, unaffected by heat stress, is high, being 56% and 64%, respectively. The effect of heat stress on JH degradation and fertility was studied in Drosophila virilis and D. melanogaster. It was shown that the lines of wild type of both species respond to stressing effects by a decrease in the level of JH hydrolysis, delay in oviposition and also by a decrease in fertility for several days after exposure to the stress conditions. Experiments with inhibition of the juvenile hormone esterase (JHE) demonstrated that a decrease in the level of JH hydrolysis may be responsible for the response of the reproductive system of Drosophila to stress. It was shown that the in lines of Drosophila not responding to stressing agents by a decrease in the degradation level of JH, fertility is not altered under stress conditions. The role of JH in the reproduction of Drosophila under stress and in the adaptation of natural populations of Drosophila to stressing agents is discussed.