Mortality Oscillations Induced by Periodic Starvation Alter Sex-Mortality Differentials in Mediterranean Fruit Flies

Sex-specific mortality ratesofmedfliesweremonitaredin cagescontainingindividuals ofbothsexesand withfood (either sugar-onlyorfull diet)removedevery2nd, 3rd,or4th day (plusad libitum controls). The generaljinding is thatperiodic starvationled to markedoscillationsin raw mortalityrates. The specijicjindings areasfollows: (i)female medfiieslive longerthan malemedflies whentheyaresubjected to periodic starvation; (ii) malemedflies maintainedon afulldietexperi-encea catastrophic increase in mortality(40%) on thejirst dayfood is removed. Thismortality surge wasnot observedfor females on eitherdietorfor malesmaintainedon a sugar-only diet;(üi) life expectancy is inversely relatedto the amplitude ofmortality oscillations causedbyfood deprivation; and (iv)the largeperturbations in mortality atyoungeragescausedby periodicstarvation has littleeffecton the amplitudeofmortalityat olderages.In general, our datashed new light on the complexityofthe mortality response ofmedfliesto boththe typeand availability offood and thusprovidea complimentary perspective tojindingsfrom dietary restriction studies on bothvertebrate and invertebrate systems. ORGANISMS have evolved a wide range of physiologicaladaptations to increase their survival when food is scarce, including the ability to enter arrested states (1), draw on fat re-serves (2), reduce metabolic rates (3), and postpone aging (4). Despite the large amount of research that has been conducted on physiological and actuarial responses of organisms to nutri