Metabolic pool, metabolic rates and diapause in Drosophila melanogaster.

摘要

Diapause, a period of suspended growth or development, decreased metabolic rate and cessation of reproduction, allows invertebrates to survive over unfavorable seasonal events subsequently increasing their life span and resuming reproduction when conditions become more favorable. Drosophila melanogaster exhibits a type of reproductive diapause. In D. melanogaster, diapause extends longevity and increases stress resistance. D. melanogaster is a unique species in that it has variation for the expression of the diapausing phenotype, thus allowing comparisons of the nondiapausing and diapausing genotypes in the same species. I employed this system to better examine the physiological characteristics of diapause, ageing and starvation resistance. In this study, I quantified metabolic rates, lipid mass, and protein mass on 5, 15 and 25 day-old individuals from lines that are solely diapausing or nondiapausing in standard conditions and diapause-inducing conditions. I also exposed these lines to a 24 hours of starvation and the measured metabolic rates, lipid mass, and protein mass. The diapause genotype did not appear to involve modifications to metabolic pool storage or metabolic rates. Diapausing lines are not storing more or using less energy than nondiapausing lines, and the observed increased resistance to starvation and cold are not due to an increased availability of lipid or proteins. Available metabolic pools do not appear to be driving the differences in fecundity and longevity observed between the two genotypes. Diapause in D. melanogaster appears to use a pathway that does not involve modifications to metabolic storage pathways. Future research into diapause in D. melanogaster needs to focus on investigating genetic and hormonal causes.