The Waxy Secretions Of Coccidae And Its Significance In Systematics(Homoptera:Coccoidea)

The ultra-structure, infrared spectral characters and chemical composition of the waxy secretions from 14 species of scale insects belonging to 11 genera of 5 subfamilies in Coccidae are studied by applying the techniques of scanning electron microscopy (SEM), infrared spectra (JR) and gas chromatograph I mass spectrometry(GC/MS).The results are as follows:1.The waxes secreted by the Coccidae can be grouped as dry and wet wax with various micro-morphology, such as fluid, mud-like, granular, lamellar, lump-like, forming hollow thread or coiled filament. It is found by this research that the waxy substance changed their micro-morphological characters along with the different metamorphic stages. Such transformations of waxy secretion are discussed on the basis of its relationships with the metamorphic changes of wax glands.2.The coiled and hollow wax filaments are always found on the spiracular furrow and around the valva. They are secreted respectively by the quinque-locular disc-pores and the multilocular disc-pores. The relationships are discussed between the wax morphological characters and their function in providing air for breathing of the scale insect and in protecting the eggs.3.The results of the waxy secretion ultra-structure research of Coccidae are used to evaluate the two representative classificatory systems of Coccidae. The Hodgson( 1994) system is rather strongly supported by this study. Some systematic regularities revealed by the waxy micro-morphology is similar to those indicated by other morphological characters. New evidences are provided by waxy secretion in supporting of classification based on general morphology.4.The infrared spectral technique is here firstly applied on the study of scale insect wax. The infrared characteristics and patterns of the waxy secretions were workcd nut specifically and segregated into 6-groups according to the characteristicvibration absorption peaks of chemical function groups. In some extent, spectral patterns can indicate not only the systematic relationships of species and genera, but also the differences between sexes and instars of the same species. The conclusion is consistent with the micro-morphology of waxes results of this research. It is proved that the infrared spectral character of waxy secretion would be an useful tool in the systematical works on scale insects.5.The chemical components of the waxes from 10 species of Coccidae were determined by GC/MS, on the condition of esterified and unesterified. Their gas chromotogram, mass-spectrogram, molecular formulae, molecular weights, structure formulae and relative contents were obtained. Among the 10 species, 7 species are studied for the first time on the chemistry of their waxy secretions. It is revealed that the micro-morphological pattern difference of the waxes is largely congruent with those of their chemical compositions.6.Based on the results of OC!MS, it is discovered that the two populations of Ceroplastes cer~ferus inhabiting different host plants and distributional areas have the same chemical composition. On the other side, the two sibling species Eulecanium gigantea and E. kuwanai possess different chemical components. The chemical characters of waxes are expected to the valuable in the identification of scale insects.7.The systematical significance of waxy secretion and other relative problems are discussed and appraised.