| Popis: |
In indoor laboratory-cage and outdoor field-cage assays, we evaluated the attraction of released, protein-fed, mature Mediterranean fruit fly females to six volatile compounds emitted by attractive crushed ripe coffee fruit: 3-methyl-1-butanal, decanal, 3-methyl-1-butanol, 2-(Z)-pentenol, 2-(E)-hexenol, and 2-heptanone. Previous tests in a wind tunnel indicated that each of these six compounds was more attractive than clean air to females. In laboratory cage assays, none of the compounds elicited a response significantly greater than that to water. In field-cage assays, 2 or 4 μl of 2-heptanone in 5 ml of water (but none of the other compounds at 2 or 4 μl in 5 ml of water) consistently attracted protein-fed medflies at significant levels that averaged about five times greater than attraction to water alone, although about 40% less than attraction to odor of coffee fruit extract. All types of mature protein-fed females tested (laboratory-cultured virgin, laboratory-cultured mated, wild mated) in field-cage assays responded similarly to 2-heptanone, whereas same-age (9- to 11-day-old) protein-deprived females did not respond significantly to 2-heptanone. Response of protein-fed females to 2-heptanone increased progressively with increasing dose (1, 2, 4, or 8 μl in 5 ml of water). Addition of 2 μl of 2-heptanone or 2 μl of any of the other compounds tested to 5 ml of water extract of coffee fruit did not enhance attractiveness of the extract. Relative to response to water, protein-fed females consistently exhibited a significant positive response to odor of coffee fruit extract but no significant response to odor of Nulure (a proteinaceous food attractant). Together, our findings suggest that mature protein-fed females were responding to 2-heptanone as though it were an oviposition-site stimulus rather than a feeding-site stimulus. |
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