Relation of constant, daily fluctuating, and ambient feeding temperature to daily and accumulated consumption of yeast autolysate and sucrose by female Queensland fruit fly

Intake rates by the Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), of yeast autolysate and sucrose were clearly related to temperature in constant thermal regimes, but consumption occurred only in light. In regimes of fluctuating temperature, rates of consumption were not necessarily related to the temperatures that prevailed during the photophase, but were more consistently related to daily mean temperature and best related to day degrees per day above the gonadotrophic threshold of 13.5 degrees C. Day degrees per day could be related to age-specific changes in the daily rate of yeast autolysate and sucrose consumption, the rate of accumulated consumption of these foods, and thus the time taken to consume the amount of yeast autolysate known to be required for the attainment of sexual maturity. Consumption rate changed within 1 or 2 days of a change between a gonadotrophic regime and a non-gonadotrophic one (or vice versa), which is consistent with the known rapid effects of temperature change on ovarian maturation.