Food consumption and individual lifespan of adults of the blowfly, Calliphora stygia: a test of the ‘rate of living’ theory of aging

Abstract

Following eclosion, adult Calliphora stygia were individually housed (at 22 °C and 73% RH) in 125 ml plastic vials and provided with ad libitum access to either 0.125 or 0.2 M sucrose as a food source and daily food consumption measured throughout their adult life. All blowflies were weighed daily and food consumed is determined by weighing individual food dishes. Blowflies provided with 0.125 M sucrose ( N=59) consumed daily a significantly greater amount of the sucrose solution than those provided with 0.2 M sucrose ( n=55) such that the average rates of sucrose consumption were, respectively, 1.72 and 1.96 mg sucrose day −1. There was no significant difference in the survival curves of the two populations with respective average (±SEM) lifespans being 25.4 (±1.2) and 26.5 (±1.2) days. The respective ranges of individual lifespans were 4–53 and 5–50 days. There was no statistically significant relationship between mass-specific rate of sucrose consumption and lifespan in either population but there were highly significant ( P<0.0001) correlations between lifetime sucrose consumption and lifespan in both groups of blowflies. These findings contradict the predictions of the ‘rate of living’ theory of aging. In both populations of blowflies, body mass and the rate of food consumption were relatively constant through the adult life of blowflies, except that a few days before death both sucrose consumption and body mass showed a dramatic decline.