BIOCHEMICAL COMPOSITION OF DIMORPHIC ADULTS OF THE SOUTHERN COWPEA WEEVIL CALLOSOBRUCHUS MACULATUS F. WITH REFERENCE TO ITS CONTROL

Abstract

The objective of the present study is to investigate the radiosensitivity of eggs of cowpea weevil to gamma rays. It included the effect of gamma radiation on some biological activities of the insects and also its delayed effects on the next generations. The studies included the susceptibility of the adult weevils to two botanical insecticides, viz., commercial products of pyrethrum and lemon oil extracts. The present investigations are concerned primarily with the elemental composition differentiation between the active and normal forms of the adult weevils as well as between the untreated and treated adults with gamma rays and insecticide. The study also was extended to include the effect of larval food on the elemental composition of the two forms. The atomic absorption spectrometry was used to determine quantitatively the major and trace elements, and the energy dispersive spectrometry was also used to measure some elements, which could not be detected by atomic absorption spectroscopy. Nine trace and major elements were detected including Cu, Zn, Fe, Ca and S from the trace elements and Na, Mg, K and P from the major elements. The results indicated differences in the elemental composition between morphs, sex, gamma irradiation, insecticide treatments and larval host food. In spite of the discrepancy in some obtained results, there exists an adequate relationship between the total body concentration of several major and trace elements of the natural sterile adults (active form) and those artificially sterilized by gamma irradiation. Moreover, the amount of the total body elements in the active form does not greatly differ from that of irradiated ones so that, it can be used as bioindicator or chemoprint for sterility.