Sequestration of 3-oxygenated α-ionone derivatives in the male rectal gland of the solanaceous fruit fly, Bactrocera latifrons |
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Authors: | Ritsuo Nishida Hiroshi Enomoto Todd E Shelly & Tatsuaki Ishida |
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Institution: | Laboratory of Chemical Ecology, Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan,;USDA-APHIS, 41-650 Ahiki Street, Waimanalo, HI 96795, USA, and;Naha Plant Protection Station, MAFF, Okinawa, 900-0001, Japan |
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Abstract: | The solanaceous fruit fly, Bactrocera latifrons (Hendel) (Diptera: Tephritidae), infests various solanaceous fruits including eggplant and chili peppers. We found that a freshly cut fruit of an eggplant cultivar Solanum melongena L. cv. Long Purple Oriental (Solanaceae)] selectively attracted and provoked voracious feeding behavior in adult B. latifrons males (but not in females) in an indoor test. One of the male-specific attractants/feeding stimulants in eggplant was identified as 3-hydroxy-α-ionone. Sexually mature males that fed on the eggplant pulp selectively accumulated a series of 3-oxygenated α-ionone/α-ionol analogs (e.g., 3-oxo-α-ionol and 3-oxo-7,8-dihydro-α-ionol) in the rectal gland, a suspected pheromone reservoir in male flies. Males fed on synthetic 3-hydroxy-α-ionone, 3-oxo-α-ionol, or 3-oxo-α-ionone partially biotransformed the compounds into 3-oxo-α-ionol, 3-oxo-α-ionone, and 3-oxo-7,8-dihydro-α-ionol and sequestered substantial quantities (as high as 5 µg/gland as a mixture) in a similar ratio in the rectal gland within 6 h after ingestion. These results suggest that the rectal sequestrates may serve as a sex pheromone similar to other Bactrocera species that use phenylpropanoid volatiles to attract conspecific females. |
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Keywords: | Diptera Tephritidae Solanaceae eggplant 3-hydroxy-α-ionone 3-oxo-α-ionol α-ionone analog male attractant phagostimulant pheromone biotransformation |
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