Meeting Abstract

P1.18  Monday, Jan. 4  Effects of reduced dietary intake and reduced reproduction on longevity in the lubber grasshopper DREWRY, M.D.*; WILLIAMS, J.M.; HATLE, J.D.; University of North Florida m.drewry@unf.edu

Many studies that use reduced dietary intake to produce longevity have not been able to separate the effects of reduced reproduction that correspond to the reduction in diet. A previous study on grasshoppers has shown that ovariectomized females (OVX) can live up to 30% longer than fully reproductive controls (sham). A separate study showed that grasshoppers subjected to dietary restriction (60-70% ad libitum; DR) live >50% longer than ad libitum fed controls (FD). With this study we have combined these two manipulations to test the life spans of: OVX & DR; OVX & FD; sham & DR; sham & FD. This will allow us to determine whether the treatments are additive, which would suggest that they extend lifespan in separate ways. To date, only 12.5% have died, so survivorship curves cannot be reported. However, there are strong independent effects of diet or surgery on body mass (P > 0.01), but little effect of the interaction of diet and surgery on body mass. Reproductive data from the sham groups shows a decrease in the number of eggs laid per clutch in response to DR (P < 0.0004), but no change in age at reproduction (P > 0.4999). These data suggest that our DR treatments are effective at limiting the nutrition of the grasshoppers, and that DR is reducing reproductive output but not delaying reproductive timing. In addition, there is no significant difference in the total antioxidant activity of the hemolymph among any of the groups at ~100 days (P > 0.25). Survivorship and reproductive output data will be discussed in terms of whether or not OVX and DR are additive and extending lifespan in different ways. An additional treatment of partial ovariectomy will help determine whether the level of reproduction corresponds to longevity, or if any non-zero reproduction shortens lifespan.