Intan Ahmad

A defined artificial diet for the larvae of Manduca sexta

The tobacco hornworm, Manduca sexta (Johannson) (Lepidoptera: Sphingidae), has become an important and widely used laboratory animal. It was first cultured on the foliage of its host plants (Waldbauer et al., 1964; Hoffman et al., 1966), but is now typically cultured on undefined artificial diets that contain such complex substances as wheat germ and yeast (Yamamoto, 1969; Bell & Joachim, 1976; Baumhover, 1985). A diet that includes such ingredients, each containing the gamut of nutrients, is useful for maintaining cultures but is not appropriate for most nutritional studies, including studies of dietary self-selection. We here describe a defined diet (containing no ingredients that are chemically less well characterized than linseed oil) that is suitable for studies of self-selection and other aspects of nutrition. To the best of our knowledge, no defined diet for M. sexta has been previously published. The defined diet (Table 1), a modification of Vanderzandts (1968) diet, is prepared as follows: The group A ingredients, water and agar, are poured into a flask that is capped with aluminum foil, autoclaved for 20 min, cooled for 10 min, poured into a blender with the group B ingredients, and then thoroughly mixed. When the mixture cools below 60 ~ the group C ingredients are added, the diet is blended for 5 min and then poured into plastic molds. After the diet has cooled to room temperature, each mold is wrapped with aluminum foil and stored at 4 ~ until used. Table 1. Composition of defined diet for rearing Manduca sexta larvae

The influence of trichome characters of soybean (Glycine max Merrill) on oviposition preference of soybean pod borer Etiella zinckenella Treitschke (Lepidoptera: Pyralidae) in Indonesia

Study of oviposition behavior of Etiella zinckenella Treitschke on several Indonesian local cultivars of soybean, Glycine max (L.) Merrill was conducted with multiple choice and no choice tests. This study confirmed that sequence of eggs oviposition of E. zinckenella on tropical region does not differ with other results on non-tropical region. Total number of egg deposited and oviposition frequency of E. zinckenella do not correlate with trichome density, trichome length and pod surface when they do not have a choice of host plants. On the contrary, on the condition of many host plants to choose, E. zinckenella prefers to deposit eggs on the cultivar with many short trichomes. The preference test based on soybean phenology showed that the E. zinckenella prefers R4 stage (fully filled pod) for oviposition.

Monitoring pyrethroid resistance in field collected Blattella germanica Linn. (Dictyoptera: Blattellidae) in Indonesia

The German cockroach, Blattella germanica, is a major and the most common pest in public areas in Indonesia. Although intensive control measures have been carried out to control the populations of this pest, results have been far from successful, which is believed to be because of its resistance to insecticides. A standard World Health Organization (WHO) glass jar test was carried out to determine the resistance level of this insect to pyrethroid insecticides, the most commonly used insecticides for cockroach control in Indonesia. A susceptible S1 strain collected from Tembagapura Papua was compared with four strains collected from Bandung, West Java: strain S2, from a local restaurant; strain S3, from the Bandung train station; and strains S4 and S5, from two different hotels. All strains showed low resistance to the pyrethroid, except the S5 strain, which had a Resistance Ratio (RR)50 of 95 for permethrin. The addition of piperonyl butoxide (PBO) suggests that the detoxifying enzyme mixed function oxidases (MFO) played an important role in the development of resistance to permethrin in the S5 strain, suggested by the high Synergist Ratio (SR) of 70.4. However, the low level of resistance to cypermethrin was not affected by PBO, suggesting that other mechanisms of pyrethroid resistance are involved. Our study is the first report of German cockroach resistance to permethrin in Indonesia, and the findings can be used in formulating potential strategies for cockroach resistance management.