Inhibition of Feeding, and Blood pH Changes, in Lepidopterous Larvae Infected with Crystal-forming Bacteria

Abstract

In recent years considerable work has been devoted to the Bacillus species which are pathogenic for insects. Some of these produce a proteinaceous parasporal body or crystal (8) which is toxic to a large number of insect species (11, 13). The effect of a paralytic toxin derived from cultures of Bacillus thuringiensis var. sotto on the silkworm (Bombyx mori L.) has been studied in some detail (2, 3, 4). A similar toxin has been extracted from Bacillus thuringiensis var. alesti by Fitz-James et al. (5), from B. thuringiensis var. thuringiensis by Hannay and Fitz-James (personal communication), and Bacillus entomocidus var. entomocidus Heimpel and Angus (12, also unpublished results).