SYSTEMATICS, MORPHOLOGY AND PHYSIOLOGY Laboratory Environment Effects on the Reproduction and Mortality of Adult Screwworm (Diptera: Calliphoridae)

The New World screwworm, Cochliomyia hominivorax Coquerel, is mass reared for screwworm eradication initiatives that use the sterile insect technique. New methods for rearing have helped to reduce the cost of the eradication program. We examined the effect and interaction of three temperatures (24.5, 29.5 and 34.5oC), two diets (2% spray-dried blood plus 0.05% vitamins and corn syrup carrageenan) and three population densities (300, 400, and 500 fl ies/cage) on egg production, egg hatch, number of observable fertilized eggs, mortality (male and female) and ovarian development. The three population densities did not affect any of the parameters monitored. Using the protein diet increased egg production at all temperatures. Diet did not affect egg hatch or female mortality. Male mortality was signifi cantly greater when fed the protein diet and reared at 24.5oC and 34.5oC. Egg hatch was signifi cantly less when the fl ies were reared at 34.5oC. When exposed to high temperatures (37oC and 40oC) egg production, egg hatch, fertility and mortality were adversely affected. At the higher temperatures, yolk did not adequately form during oogenesis. When compared to the normal rearing photoperiod (12 L: 12 D), short photoperiod (1 L: 23 D) increased egg production, egg hatch and fertility but lowered mortality.