Effects of new dietary ingredients used in artificial diet for screwworm larvae (Diptera: Calliphoridae)

Authors: Chaudhury, Muhammad; Chen, Hong; SAGEL, AGUSTIN - Us Embassy, Panama; Skoda, Steven

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/9/2015
Publication Date: 3/23/2015
Publication URL: https://handle.nal.usda.gov/10113/62165
Citation: Chaudhury, M.F., Chen, H., Sagel, A., Skoda, S.R. 2015. Effects of new dietary ingredients used in artificial diet for screwworm larvae (Diptera: Calliphoridae). Journal of Economic Entomology. 108(3):1429-1434.

Interpretive Summary: Spray-dried whole bovine blood, dry poultry egg, and a dry milk substitute are the constituents of the standard artificial diet currently used for mass rearing immature screwworms. Due to high cost and uncertainty of the commercial supply of spray-dried blood, research was conducted to identify alternative, locally available, inexpensive, dietary ingredients which could reduce costs and eliminate concerns of short supply. Several experimental diets were prepared without any blood component and others with various ratios of bovine animal blood cell product and defatted soy flour combined with the other ingredients used in the standard artificial diet for screwworms. Results show that spray-dried bovine blood could be replaced by the blood cell product which is readily available and less expensive. When the quantity of whole blood or blood cell component was reduced or removed completely from the diet formulation, the larvae did not feed adequately, resulting in high mortality of larvae. Those larvae that survived produced low-weight pupae that were not of acceptable quality. When the milk product was replaced by soy flour, the pupae were slightly smaller but of acceptable size; however, replacement of egg product with soy flour produced significantly smaller pupae compared to those produced by the standard diet. Longevity of most of the adult flies that emerged from these pupae was significantly short and the females deposited fewer eggs than those from the standard diet. These results indicate that soy flour, although it contains all the essential nutrients, cannot replace the bovine blood component from the diet, but could replace the milk product successfully. It is probable that the blood acts as a feeding stimulant, without which larvae are unable to feed properly which in turn results in high mortality of developing larvae.

Technical Abstract: Spray-dried whole bovine blood, dry poultry egg, and a dry milk substitute are the constituents of the standard artificial diet currently used for mass rearing screwworm larvae, Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae). Due to high cost and uncertainty of the commercial supply of spray-dried blood, research was conducted to identify alternative, locally available, inexpensive, dietary ingredients which could reduce cost and eliminate concerns of short supply. Several experimental diets were prepared without any blood component and others with various ratios of bovine animal blood cell product and defatted soy flour combined with the other ingredients used in the standard artificial diet for screwworms. Results show that spray-dried bovine blood could be replaced by the blood cell product which is readily available and less expensive. When the quantity of whole blood or blood cell component was reduced or removed completely from the diet formulation, the larvae did not feed adequately, resulting in high larval mortality. Those larvae that survived produced low-weight pupae that were not of acceptable quality. When the milk product was replaced by soy flour, the pupae were slightly smaller but of acceptable size; however, replacement of egg product with soy flour produced significantly smaller pupae compared to those produced by the standard diet. Longevity of most of the adult flies that emerged from these pupae was significantly short and the females deposited fewer eggs than those from the standard diet. These results indicate that soy flour, although it contains all the essential nutrients, cannot replace the bovine blood component from the diet, but could replace the milk product successfully. It is probable that the blood acts as a feeding stimulant, without which larvae are unable to feed properly which in turn results in high larval mortality.