Rearing the oligophagous Cactoblastis cactorum (Lepideptera: Pyralidae) on meridic diets without host plant materials

Authors: Carpenter, James; Hight, Stephen

Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/25/2012
Publication Date: 12/1/2012
Citation: Carpenter, J.E., Hight, S.D. 2012. Rearing the oligophagous Cactoblastis cactorum (Lepideptera: Pyralidae) on meridic diets without host plant materials. Florida Entomologist. 95(4):1132-1141.

Interpretive Summary: Cactoblastis cactorum (Berg), the South America cactus moth, has been used successfully as a biological control agent for several invasive prickly pear cacti (Opuntia species) around the world. However, its unintentional arrival in Florida raised serious concern over its possible effect on native Opuntia biodiversity and Opuntia-based industries. Development of control tactics to mitigate the threat of this invasive pest to North America relied upon a constant supply of all life stages of this species. Therefore, three strains of C. cactorum were established in a laboratory insectary and trials were initiated to optimize rearing methods using an artificial diet. Because moth larvae which have a limited host range may be sensitive to the balance of nutrients and/or the presence of specific feeding cues and may respond differently to various artificial diets, we compared the development and survival of three strains of C. cactorum on several artificial diets containing different non-host proteins. Although C. cactorum usually attack only cacti within the genus Opuntia, it accepted and developed on several non-host plant, yeast, and animal proteins. The source and balance of non-host proteins significantly affected all reproductive parameters. The best performance of C. cactorum was on diets that contained white kidney beans, brewer’s yeast, wheat germ and/or soybeans as protein sources.

Technical Abstract: Cactoblastis cactorum (Berg), an oligophagous Opuntia spp. herbivore from South America, has been used successfully as a biological control agent for several invasive Opuntia species around the world. However, its unintentional arrival in Florida raised serious concern over its possible effect on native Opuntia biodiversity and Opuntia-based industries. Development of control tactics to mitigate the threat of this invasive pest to North America relied upon a constant supply of all life stages of this species. Therefore, three strains of C. cactorum were established in a laboratory insectary and trials were initiated to optimize rearing methods using an artificial diet. Because monophagous or oligophagous lepidopterans may be sensitive to the balance of nutrients and/or the presence of specific feeding cues and because different strains of an oligophagous lepidopteran may respond differently to various meridic diets, we compared the development and survival of three strains of C. cactorum on several meridic diets containing different non-host proteins. Although C. cactorum is an oligophage within the genus Opuntia, it accepted and developed on several non-host plant, yeast, and animal proteins. The source and balance of non-host proteins significantly affected all reproductive parameters. The best performance of C. cactorum was on diets that contained white kidney beans, brewer’s yeast, wheat germ and/or soybeans as protein sources.