Carbohydrates in the Honeydew Excreted by Ceroplastes pseudoceriferus (GREEN)

Abstract

Carbohydrate composition of the honeydew excreted by Ceroplastes pseudoceriferus (GREEN) and of tea twigs on which the the scale insects live, were analyzed by paper chromatography.
In the honeydew, glucose, maltose, raffinose, stachyose, ribitol, and D-mannitol were detected. Ribitol and D-mannitol were isolated as crystals from the honeydew. Carbohydrate composition of the honeydew varies with clones of tea plant on which the insects live.
In the tea bark, fructose, glucose, sucrose, maltose, raffinose, stachyose, and ribitol were detected. The relative amount of these carbohydrates was assumed to be in the following order: sucrose>glucose>fructose=raffinose>maltose=stachyose>ribitol. The presence of D-mannitol could not be confirmed in the tea bark.
From these results obtained it was suggested that Ceroplastes pseudoceriferus (GREEN) living on tea twigs mainly utilizes fructose and sucrose contained in their food. It is possible to assume that ribitol ingested by the scale insect was excreted without any change.
The fact that the reducing sugars content of the honeydew of the scale insect is remarkably smaller than that of aphids, seems to indicate that waxy substances of the scale insect would mainly be originated from the reducing sugars in the tea plant.