Appropriate number of inoculated eggs for mass-rearing the West Indian sweet potato weevil, Euscepes postfasciatus (Coleoptera: Curculionidae)

It is necessary to establish an economical mass-rearing system for the West Indian sweet potato weevil Euscepes postfasciatus (Fairmaire) so that large numbers can be created for use in the sterile insect technique (SIT) to control wild infestations. Both the quality of offspring and the number of adult weevils produced are important. As an adult female with a dry weight of less than 1.4 mg has an extremely low rate of production of offspring, we investigated the effect of an inoculated dose of egg suspension on both yield rate and body size, in order to determine the appropriate dose to attain the maximum yield of productive females. The number of emerged weevils increased as the inoculated dose of egg suspension increased. In brief, both yield rate and female body size significantly decreased as the inoculated dose of egg suspension increased, perhaps as a result of density effects. We conclude that the appropriate dose of inoculated egg suspension to attain the maximum yield from productive females of E. postfasciatus in the current mass-rearing system is 3 mL (containing approximately 450 eggs) per rearing container.