BUSKIRK, MC*; HAHN, DA; Univ. of Florida; Univ. of Florida: Starvation reveals critical larval body size for adult development in the flesh fly, Sarcophaga crassipalpis.

Documenting the regulation of cellular growth and proliferation during development is essential for understanding both normal ontogeny and disease phenotypes. Diapause-destined individuals of the flesh fly Sarcophaga crassipalpis grow substantially larger during larval development than their non-diapausing counterparts, making this species a natural model for studying cellular growth and proliferation. A controlled starvation experiment was used to determine the larval body size threshold for successful pupariation and progression to adult development in non-diapause individuals, and to generate a range of adult body sizes. Starved individuals were observed for pupariation and subsequent eclosion, at which points weight and body size measurements were recorded. As expected, survival rate and body size increased with the number of days spent feeding. Larvae extirpated on or before the third day after deposition did not survive, though removal on day 4 resulted in a 66% survival and pupariation rate. All larvae isolated at day 5 or later successfully pupated. This suggests that a threshold for minimum feeding time exists between days 3 and 4 of larval development. The critical weight at this threshold for pupariation and subsequent adult development is estimated at 35 mg, which is approximately 25% of the mean weight of larvae allowed to progress through development undisturbed with ad libitum food. In addition, the ability to produce individuals over a range of body sizes as demonstrated by this study will allow us to determine the importance of body size to survival and fecundity in both diapausing and non-diapausing individuals.