The biology and behaviour of Bphestia calidella and E.figulilella were studied in the laboratory, and a comparison made with the biology of the closely related storage pest E.cautella, and the pre-harvest species, Ectomyelois ceratoniae. Factors affecting the laboratory rearing of each species were investigated, and improvements in existing culture methods described. Ectomyelois required greater space for mating than the other species, and its requirements for light were more critical. Fluctuating temperature and humidity, and air-circulation inside the mating cage also improved fertility. A laboratory stock of Ephestia cautella, reared under constant conditions for four years, was less fertile and less adaptable to changes in rearing conditions than a fresh warehouse stock. The effects of constant temperature and humidity, and different light regimes on the development of each species were studied. Optimum conditions for development for all species were 30°C. 70%r.h. and between 14L/10D and 16L/8D photoperiod. Ephestia calidella, E.figulilella and Ectomyelois exhibited a larval diapause induced by short-day photoperiods. Exposures to carbon dioxide and long-day photoperiods were used to terminate diapause in Ephestia calidella. The suitability of various natural and semi-artificial diets was assessed. E.cautella was the most successful species on stored foodstuffs, and Ectomyelois the least successful. Diets rich in glucose and glycerol were more suitable for Ephestia figulilella and E.cautella than for the other species. Differences in chorion microstructure were studied under the scanning electron microscope, and their use in the identification of Phycitids considered. The adaptation of each species to its particular habitat was discussed. Ectomyelois was less able to colonize the storage environment than the other species because of its food, light and space requirements. Ephestia calidella and E. figulilella were found to have considerable potential as storage pests.
|Date of Award||1973|