ARS | Publication request: Evaluation of waste artificial larval rearing media as oviposition attractant for New World screwworm (Diptera: Calliphoridae)

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 16, 2011
Publication Date: March 15, 2012
Citation: Chaudhury, M.F., Sagel, A., Skoda, S.R. 2012. Evaluation of waste artificial larval rearing media as oviposition attractant for New World screwworm (Diptera: Calliphoridae). Journal of Medical Entomology. 49(2):293-298.

Interpretive Summary: There are many naturally occurring chemical and physical factors which play behavior-modifying roles in insects. Egg-laying behavior of the New World Screwworm appears to be under the influence of some of these factors. In this research, the spent, artificial media, based on gel or cellulose fiber as bulking agents, that remained after the screwworm larvae were reared was evaluated for effectiveness as an attractant and stimulant for egg-laying for the adult female screwworm flies. Various concentrations of waste larval media containing either bulking agent were evaluated over a 4-week period. Treatments with 10 and 25% three-day-old waste medium were most attractive to gravid female flies for egg-laying. One-day- and seven-day-old waste media at all concentrations were less attractive for egg-laying than three-day-old media. The media tested on the same day of collection, as well as those that were two weeks and four weeks old were the least attractive for egg-laying. The waste from the cellulose fiber-based diet resulted in significantly more eggs compared to the waste from the gel-based diet. Microorganisms growing in the waste media most likely produce metabolites which attract gravid screwworm flies to deposit eggs. It is hypothesized that the waste products of appropriate age and dilution as attractant substances will increase egg production, thereby realizing eficiencies in the mass rearing of screwworms.

Technical Abstract: The waste artificial larval rearing media of the New World Screwworm, Cochliomyia hominivorax (Coquerel) were evaluated to determine their effectiveness as oviposition attractants. Various concentrations of waste larval media resulting from rearing screwworm larvae in gel and cellulose fiber-based artificial diets tested over a 4-week period attracted varying numbers of gravid screwworm flies to oviposit. Three-day-old waste medium with concentrations of 10 and 25% were most attractive to gravid female flies for oviposition and resulted in most oviposition. Waste from one and 7-day-old media at all concentrations were less attractive for oviposition than the 3-day-old media. Fresh (0-day-old), 14-day- and 28-day-old waste media were the least attractive substrates for oviposition. Waste from the cellulose fiber-based diet resulted in significantly more oviposition compared to waste of gel-based diet. Microorganisms growing in the waste media probably produce metabolites which attract gravid screwworm flies to oviposit. It is hypothesized that the waste products of appropriate age and dilution as oviposition substrates will enhance oviposition in the mass production colony cages, thereby increasing the overall efficiency of mass rearing screwworms.