Abstract: In order to understand the interactive mechanisms of Aphis gossypii Glover and its host plants, the changes in major body constituents, viz. crude protein, fat, sugar, amino acid and fatty acid, of A. gossypii on five host plants, viz. Cucumis sativus, Cucurbita moschata var. melonaeformis, Cucurbita pepo var. medullosa, Lagenaria siceraria var. turbinata and Cucumis melo var. saccharinus, were investigated by micro-Kjeldahl method, Soxhlet extraction, anthrone colorimetry, hydrochloric acid hydrolysis method and gas chromatography, respectively. The results showed that the contents of the above constituents were significantly different among the aphids reared on different host plants. The dried aphids contained 35.40%-45.25% crude protein, 24.01%-30.33% fat and 4.09%-7.91% sugar depending on the host plants. Eighteen amino acids existed in the body of the aphid, mainly glutamate (5.15-6.97 mg/100 mg, dry weight), aspartic acid (3.75-5.33 mg/100 mg) and leucine (2.59-3.60 mg/100 mg), and the least was cystine (0.44-0.49 mg/100 mg). There were 8 kinds of fatty acids in the aphids. The highest content was palmitic acid (10.53%-15.55%), then myristic acid (3.32%-9.93%), and the least was linolenic acid (0.04%-0.17%) in the aphids fed on the other four host plants except for L. siceraria var. turbinata, on which the most abundant was myristic acid (16.20%) and the second abundant palmitic acid (7.15%). The dried aphids contained 20.08%-27.72% saturated fatty acids and 2.58%-3.84% unsaturated fatty acids. The results suggest that the host plants affect significantly the major body constituents of A. gossypii.

Key words: Aphis gossypii, host plant, body constituents, amino acid, fatty acid