Relationship between life expectancy, endogenous antioxidants and products of oxygen free radical reactions in the housefly, Musca domestica.

The general objective of this study was to identify biochemical correlates of life expectancy in the adult male housefly. All houseflies lose flying ability prior to death, whereby, in an aging population, shorter-lived flies can be identified as flightless 'crawlers' from their longer-lived cohorts, the 'fliers'; the average lifespan of crawlers is about one-third shorter than the fliers. Neither crawlers nor fliers exhibited any physical damage to their chemoreceptive tarsi, thereby ruling out starvation as a probable cause of death. Levels of antioxidant defenses (superoxide dismutase, catalase and glutathione) and products of oxygen free radical reactions (inorganic peroxides and thiobarbituric acid [TBA]-reactants) were compared between crawlers and fliers. The fliers showed higher superoxide dismutase and catalase activities and glutathione concentration than crawlers, whereas, the amount of inorganic peroxides (H2O2) and TBA-reactants was higher in the crawlers than in fliers. Results of this study demonstrate, for the first time, that longer life expectancy of organisms belonging to the same cohort group is associated with relatively higher levels of antioxidants and lower concentrations of products of oxygen free radical reactions.