| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1990: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1989: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
Fruit flies of the family Tephritidae cause some of the greatest economic losses of any of the economically important pest insects. Specific male attractants, methyl eugenol for the oriental fruit fly (Dacus dorsalis) and cuelure for the melon fly (Dacus cucurbitae), have been used as the powerful mass trapping agents and the population-monitoring bates in the eradication program of these insects. However, the biological significance of such specific attraction of the lures for the male dacine flies has not yet been clarified. This study has been undertaken to clarify the ecological function of these fruit fly attractants.
A number of plants contain methyl eugenol as the essential oil. D. dorsalis males visit the plants, feed on the plant tissues to acquire the essential component. Two phenylpropanoid compounds which are closely related to methyl eugenol were found in the rectal glands of wild males, which were emitted to the air during courtship period, suggesting any pheromonal function of the component. Allomonal function was also determined using predatory animals. Flowers of Spathiphyllum communatum (Araceae) attract some subspecies of D. dorsalis, but has no significant quantities of methyl eugenol. Instead, several other related compounds were indentified from the flower.
Flowers of Dendrobium superbum emit fragrance which strongly attracts D. cucurbitae males. The attractant chemical was identified as 4-(phydroxyphenyl)-2-butanone. The male fly selectively accumulated the compound into the rectal glands, suggesting a pheromonal role during courtship.
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