Author
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Crafts-Brandner, Steven |
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Submitted to: Sweetpotato Whitefly Progress Review Proceedings
Publication Type: Abstract Only Publication Acceptance Date: 5/1/2000 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Our objective was to determine how short-term alterations in N nutrition influenced the free amino acid composition of adult silverleaf whiteflies. Insect N nutrition was altered by feeding whiteflies for 2-to-4 days on N- stressed muskmelon plants or on artificial feeders. Free amino acid levels and composition were similar in whiteflies fed on N-sufficient and N- stressed plants. Glutamine was the predominant amino acid in the whitefly bodies, but in all cases we detected a very high level of an amino compound that eluted with the same retention time as proline. In contrast to amino acid levels in the whitefly bodies, the honeydew amino N was markedly reduced for insects feeding on N-stressed plants. This effect was even more pronounced for insects feeding on an artificial diet of 15% sucrose, where amino N was essentially non-detectable after 2 days. As for the insect bodies, glutamine was the predominant amino acid in the honeydew. Proline, however, was detected in very low levels in the honeydew. These results indicate that honeydew composition is quite sensitive to insect N nutrition, thus providing a good indication of N supply to the insect. Although insect amino-N level was not altered by short-term alterations in N nutrition, the rapid effect of N supply on honeydew amino N levels indicates that longer-term exposure to a low-N diet may influence insect N composition and, perhaps, performance. |
