Sweet Potato Hornworm, Agrius convolvuli, as a New Experimental Insect: Growth and Development under Rearing Using Artificial Diets.

Abstract

We developed a continuous rearing system for the sweet potato hornworm, Agrius convolvuli, for use as a new experimental insect for studies on insect biology. This species is closely related to the tobacco hornworm, Manduca sexta, which has occupied an important position as an experimental animal. By modifying the artificial diet for the silkworm, Bombyx mori, diets suitable for Agrius convolvuli were developed. The diets contained various amounts of sweet potato leaf powder as a substitute for mulberry leaf powder. Among the five different diets prepared, SPLP-25 and SPLP-20 (ca. 17-22% leaf powder) were suitable for the first four instar larvae, while SPLP-10 and SPLP-5 (ca. 4-9% leaf powder) for the final 5th instar. Although most of the 5th instar larvae fed and grew on a diet designated as SPLP-0 lacking leaf powder, larval life was prolonged and the resultant pupae were smaller. Year-round egg collection and rearing system were developed after a slight modification of the system devised for Manduca sexta. The sweet potato hornworm was successfully reared on the artificial diet for over 20 generations during the past 3 years under this system. The insect is considered to be a good experimental animal suitable for comparative studies with other large lepidopteran insects, such as Manduca sexta and Bombyx mori.