Variations in gustatory response to amino acid-sucrose solutions among biotypes of the
brown planthopper
K. Sogawa, visiting scientist from the Tropical Agriculture Research Center (TARC),
Entomology Department,
International Rice Research Institute
The gustatory blockage of sucking has been established as the principal cause of varietal resistance of rice
to the brown planthopper Nilaparvata lugens. Biotypes 2 and 3, which can infest resistant rice varieties,
have also been shown to have better ability than biotype 1 to feed on resistant varieties. This leads to the
assumption that the differential abilities of biotypes to feed on resistant varieties may be due to
differences in their gustatory response to dietary substances in different rice varieties.
To verify this, the acceptability of various types of amino acid-sucrose solutions to the three biotypes was
compared. Thirteen types of amino acid were individually subjected to the sucking of female adults of
each biotype. Each amino acid was dissolved in a basic solution (20% sucrose and 0.2% aspartic acid, pH
6.5) at 0.2% concentration. The insects were allowed to feed on the solutions through a parafilm
membrane.
The amount of sucking was estimated by colorimetric measurements of excreted honeydew. The solutions
containing asparagine, glutamine, proline, and hydroxyproline were significantly more acceptable to
biotypes 2 and 3 than to biotype 1 (see figure). Those amino compounds are not always major
constituents in rice plants. Likewise, the sucking of biotypes 2 and3 was enhanced by alanine, gammaaminobutyric acid, glutamic acid, glycine, and valine. But all biotypes took up cysteine, leucine,
methionine, and serine almost equally. It is noteworthy that no amino acid-sucrose solution was more
acceptable to biotype 1 than to biotypes 2 and 3. That indicates that biotypes 2 and 3, which break host
resistance, have wider adaptability to unusual dietary substances. That may partly explain their ability to
feed on resistant varieties.
Acceptability of different kinds of amino acid — sucrose solutions to the time biotypes of brown planthopper.
Sogawa, K. 1978. Variations in gustatory response to amino acid sucrose
solutions among biotype of the brown planthopper. Int. Rice Res. Newsl.
3(5):9.