Fatty Acids, Alcohols and Hydrocarbons in the Waxy Covering of Ceroplastes pseudoceriferus GREEN, Ceroplastes japonicus GREEN and Ceroplastes rubens MASKELL (Homoptera : Coccidae)

Abstract

Wax materials of waxy covering secreted by mature adults of three scale insects belonging to genus Ceroplastes were analyzed chemically with special interest in the compositions of higher fatty acids, higher alcohols and higher hydrocarbons. The ethanol insoluble fractions of the wax materials obtained from the three scale insects consisted mostly of esters. Amounts of straight chain esters were smaller than esters composed of cyclic (or branched chain ) alcohols and normal fatty acids. Free acids were also detected in the ethanol insoluble fractions from C. japonicus and C. rubens. The higher fatty acids were found to be mixtures of from 9 to 11 normal acids of even carbon number, i.e., 9 acids ranging from C_<16> to C_<34> (major acids : C_<30>, C_<32> in C. pseudoceriferus. 9 acids ranging from C_<18> to C_<34> (major acids : C_<32>, C_<34> in C. japonicus, and 11 acids ranging from C_<18> to C_<38> (major acids : C_<32>, C_<34>, C_<36> in C. rubens. The higher alcohols were four normal alcohols of even carbon number ranging from C_<24> to C_<30>. Of these, C_<25>-alcohol was the major component in C. pseudoceriferus and C. japonicus, but C_<28>-alcohol was the major one in C. rubens. Three to four hydrocarbons of odd carbon number ranging from C_<27> to C_<33> were detected in the three species. In respect of chemical properties of their waxes, C. japonicus seems to take an intermediate position between C. pseudoceriferus and C. rubens. Percentage of higher molecules of fatty acids and alcohols is larger in C. rubens than these in the other two soil species. It can be explained that the hardness of the waxy covering of C. rubens depends on chemical natures of fatty acids and alcohols mentioned above.