The effect of an artificial diet on the developmental rate, a life history parameter, was examined for the swallowtail butterfly, Papilio xuthus. Artificial insect diets are an essential component of many insect rearing systems that produce insects for research purposes. Complex agar-gelled diets are generally prepared in large batches and used shortly after preparation because the degradation of perishable diet ingredients, such as vitamins and fatty acids, can adversely affect insect quality (Brewer F D 1984). However, the timing of diet preparation may be inconvenient and large batches wasteful if the unused, excess diet is discarded. This study showed that if the artificial diet was fed during the larval stage, the larval and pupal developmental periods, the percentage of pupation, and the pupal weight generally did not differ significantly among the five artificial diets evaluated. The percentage of pupation varied considerably, with no significant differences among diets except for diet C. A maximum pupation percentage of 83% was observed on diet C. Pellet-type diets were investigated with the aim of developing a more easily prepared diet. The extrusion of the artificial diet under high temperature and pressure may induce desirable chemical and physical changes in the extruded product. The purpose of the present study was to develop an artificial diet for rearing P. xuthus.

Development of pellet-type artificial diet for insect was tried by using a twin screw extruder(TSE). Screws were arranged several times and two reverse screws were equipped on the foreparts of 2 axes of TSE. Pellet-type diet could be produced successfully under conditions of TSE set as the following. , 300 rpm of main motor speed, 228 rpm of feed motor speed, 75㎖/min of running water speed and 5 ㎜ of extrusion diameter. The optimum adding quantity of water to the manufactured diet was 1.2~1.5 times of dry diet. On the rearing results of beet armyworm, Spodoptera exigua and common cutworm, Spodoptera litura with the pellet-type diet, the final survival ratio (emergence rate) of these two species was over than 50%, and so it was concluded that the manufactured pellet-type artificial diet was sufficient dietetically to rear those insects.