Artificial diet trials for the butterfly Jalmenus evagoras (Lepidoptera: Lycaenidae)

Abstract

Rearing insects can be costly and time consuming, particularly if their food source is a living plant. Thus, it is often more efficient to raise insects on artificial diets. Most successful artificial diets have a nutritional composition and physical texture that is similar to the insect’s natural food. The basic nutritional components of an artificial insect diet are proteins, carbohydrates, lipids, vitamins, and minerals, just like human diets. Butterflies and moths (Lepidoptera) are commonly used in experiments and, as larvae, most feed on plants. For many reasons the majority of diets developed for lepidoterans have been devised for moths, not butterflies. Because butterflies tend to have more specific dietary preferences, they do not usually accept artificial diets originally devised for moths. The endemic Australian butterfly Jalmenus evagoras (Lycaenidae) has been used as a model organism in research regarding symbiose between ants and butterflies. In order to study this symbiosis, the cultivating of both partners in the laboratory is required. All species of Jalmenus feed on plants in the genus Acacia, which are time consuming and somewhat labor intensive to grow in a greenhouse. Therefore, it would be beneficial to develop an artificial diet on which to rear the Jalmenus larvae. There have been no publications on artificial diets specifically used for rearing J. evagoras caterpillars, but diets developed for other lepidopterans, and butterflies in particular, can be used as a starting point. The purpose of this study was to develop an artificial diet that allowed for successful development of J. evagoras larvae and that resulted in healthy, viable adults comparable to butterflies reared on host plant cuttings. To achieve this I prepared a range of Lepidoptera diets found in the literature. I monitored larval survivorship and development and compared these measures to those of larvae reared on fresh host plant cuttings alone. Diets which showed promising results were then modified in an attempt to increase their effectiveness.