JAMES, LN*; HAHN, DA; University of Florida; University of Florida: Adult starvation reveals critical feeding threshold for reproduction in the flesh fly, Sarcophaga crassipalpis.
The quality, quantity, and temporal availability of nutritional resources acquired during adult feeding have long been recognized as important factors influencing insect reproduction. However, numerous insects carry significant larvally derived nutritional reserves into adulthood and our understanding of the relative importance of larvally derived vs. adult derived resources with respect to reproduction is poor. In this study we manipulated protein availability in adults to determine the effects of resource availability on reproductive timing and fecundity in the flesh fly, Sarcophaga crassipalpis. Flies were assigned to one of four food treatments, no liver, liver for two days after eclosion, liver for four days after eclosion, and liver for six days after eclosion. Water and sugar were provided ad libitum. Flies provided no protein did not produce mature eggs. The group fed through day six maintained a normal reproductive cycle producing mature eggs at the same time as non-restricted individuals. Flies fed through day four matured normal eggs which successfully hatched into larvae, but took longer to do so. Flies fed for only two days produced fewer mature eggs and took the longest amount of time to do so. This study suggests that flies receiving only two days of food can successfully produce eggs, although fewer and after a significantly greater amount of time than those fed longer. These results indicate that the critical threshold of protein intake for female flesh flies to produce mature eggs is between one and two days of adult feeding. Characterizing this threshold will provide the foundation for understanding the contributions of resources derived from larval and adult feeding to reproduction.