Submitted to: Florida Entomologist
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/1/2004
Publication Date: 12/10/2004
Citation: Teal, P.E., Gavilanez-Slone, J.M., Dueben, B.D. Effects of surcrose in adult diet on mortality of males of Anastrepha suspensea (Diptera: Tephritidae). Florida Entomologist. 87(4):487-491. Interpretive Summary: The Caribbean fruit fly is a pest of significant importance to the citrus and vegetable industries in Florida. One way to control this pest is the sterile insect technique (SIT). Control is achieved in SIT by mass release of sterile males who mate with wild females. Wild females that mate with sterile males do not produce viable eggs which, over time, results in population decline and eradication. One of the more significant costs associated with SIT protocols for the Caribbean fruit fly is the need to hold mass reared adult flies for as many as 7 days prior to release because males require time to become sexually mature. Minimizing the costs associated with adult holding is a key element in improving efficacy of SIT management protocols. One way to do this is to minimize the expense associated with feeding adult flies prior to release. Scientists at the Center for Medical Agricultural and Veterinary Entomology, USDA-ARS, Gainesville Florida, have been studying how diet affects survival of adult Caribbean flies in hopes of developing a cost effective way to feed sterile males for use in SIT. They have discovered that sugar is a critical element in the diet of the flies and that without sugar flies live for only about 2 days. The results show clearly that sugar can not be excluded from the diet used to feed sterile males prior to release and that a continuous supply of sugar is critical to survival. This will aid in strategies being devise to reduce the cost of SIT because we now know that sugar can not be excluded from the diet fed to adults.
Technical Abstract: The survival of adult male Caribbean fruit flies fed sucrose and protein in the form of hydrolyzed brewers yeast was studied under greenhouse conditions. Flies fed either a 3:1 mixture of sucrose and protein (optimal) or just sugar from the day of adult eclosion showed no appreciable mortality during the 14-day test period. However, flies fed just protein or which were not provided with sugar or protein showed rapid rates of mortality with 50% mortality occurring at 1.87 and 1.53 days, respectively, and 95% mortality occurring at 2.8 and 2.5 days. Switching flies from the optimal diet to either the protein-only diet or nothing at 7 or 11 days after emergence resulted in values for both 50% and 95% mortality that were similar to those for flies reared from eclosion on either just protein or nothing. No significant mortality occurred among males maintained on the optimal or sugar-only diets or when flies were shifted from the optimal diet to only sugar at either day 7 or 11 after emergence. The data demonstrated that flies had an absolute requirement for carbohydrate in the adult diet and maintained very limited stores of available glycogen or trehalose in either fat body, muscle or hemolymph. Additionally, the inability of flies to convert amino acids from protein hydrolysate into precursors useful for generating metabolic energy indicated that adult males probably lack transaminases required for generation of pyruvate, oxaloacetate or -ketoglutatrate for use in the Krebs cycle.