Scanning Electron Microscopic Observation of the Waxy Substances Secreted by Some Scale Insects

Abstract

The shape and fine structure of the waxy substances secreted by scale insects appeared to be species characteristic, when examined under scanning electron microscope. In Lecanium horii, Icerya purchasi and Pseudaulacaspis pentagona the outermost surface of the eggs was covered with numerous waxy substances mostly in one- or two-pitch coil form. The egg sac of L. horii, Phenacoccus pergandei and I. purchasi constituted a mass of network structure with long-tubular waxy substances. It was also found that the waxy substances secreted on the dorsum of the male first instar larvae of Ericerus pela could be classified into two types, one the coil form and the other the long-tubular form, while the surface of the adult female was covered with numerous long-tubes only. The waxy substances secreted on the dorsum of the second instar larvae of Ceroplastes pseudoceriferus, C. japonicus, and C. rubens were found to be piled up, one layer plate upon the other, and they were observed in a regular net structure on the marginal area of the dorsum of C. pseudoceriferus and C. japonicus. In the first instar larvae of P. pentagona a pair of horn-shaped waxy substances and some thread-shaped waxy substances were observed on the body surface.
Some of the chemical constituents of the waxes obtained from the egg sac, egg surface or body surface were determined by gas-liquid chromatography, and the relationship between structure and function of the waxes was discussed.