Effects of age and lifetime flight behavior on flight capacity in Drosophila melanogaster

The effects of behavior on physiology and senescence may be profound in flying insects, which attain among the highest metabolic rates ever measured. Previous studies have shown that flight capacity in insects decreases with age, and that limiting flight behavior extends lifespan and slows the age-related loss of antioxidant capacity and accumulation of oxidative damage in flight muscles. In this study, we tested the effects of age and lifetime flight behavior on flight kinematics and flight capacity by measuring wing beat frequency and the ability to fly in a hypo-dense gas mixture in Drosophila melanogaster. Specifically, 5-day old adult flies were separated into three life-long treatments: (A) those not allowed to fly (no flight), (B) those allowed – but not forced – to fly (voluntary flight), and (C) those mechanically stimulated to fly (forced flight). Flight capacity senesced earliest in flies from the no-flight treatment, followed by the forced-flight group and then the voluntary flight group. Wing beat frequency senesced with age in all treatment groups but was greatest in the forced flight group. Senescence of wing beat frequency and flight capacity in the forced flight group was likely due to use effects such as the rapid accumulation of damage at the cellular level, while the early loss of flight capacity in the no-flight group demonstrates that disuse effects can also significantly alter senescence patterns.