The Effects of Stress-Related Hormones on the Stress Resistance in Drosophila melanogaster Carrying Mutation in the Dilp6 Gene

The heat stress resistance of Drosophila melanogaster females carrying a hypomorphic mutation of the DILP6 insulin-like protein gene (dilp6 41 ) under a change in the level of stress-related hormones (juvenile hormone and octopamine) is studied. It is revealed that the dilp6 41 mutation decreases the heat stress resistance of mature D. melanogaster females. An experimental decrease in the level of juvenile hormone is shown to restore the stress resistance of mutant females to the level of stress resistance observed in wild type Canton S females. These data suggest that the effects of the dilp6 41 mutation on the stress resistance of females are mediated by an increased level of juvenile hormone. An experimental increase in the octopamine level that causes an increase in juvenile hormone level supports this hypothesis: the resistance to heat stress decreases in females of both lines and this decrease is more significant in mutant females than in the control line. Thus, it is established for the first time that the effect of the hypomorphic dilp6 gene mutation on the heat stress resistance of D. melanogaster females is mediated by juvenile hormone.