Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/5/2007
Publication Date: 6/2/2007
Citation: Borges, M., Aldrich, J.R., Oliver, J.E., Birkett, M., Chiba, M., Murata, Y., Chuman, T., Laumann, R., Barrigossi, J., Pickett, J. 2007. Sex attractant pheromone from the rice stalk stink bug, tibraca limbativentris stal (hemiptera: pentatomidae. Journal of Chemical Ecology, 32:2749-2761 Interpretive Summary: One member of the so-called stink bug family is an economically important pest of rice in South America. Strategies to control this pest rely on carefully monitoring the crop for the presence of the pest. Using traps baited with an artificial version of the attractant used by the bugs themselves to find each other for mating would be the most efficient means to detect when and where this pest occurs at potentially damaging levels. An international team of scientists from Brazil, the U.S., Britain, and Japan succeeded in identifying and making the natural attractant (pheromone) produced by this rice pest. This information may prove useful to growers and pest managers in S.A. to improve monitoring of this rice pest, and the results extend the scientific knowledge of the types of chemicals used by these kinds of insects to communicate.
Technical Abstract: The male-produced sex pheromone from the Brazilian rice stalk stink bug is reported. Olfactometer bioassays with sexually mature males and females showed that males attracted females, suggesting that males release a sex pheromone for this species. Males were not attracted to either sex, nor were females attractive to conspecific females. Attraction of the females to males was greatest in late afternoon into early evening. The headspace volatiles collected from male and female Tibraca limbativentris were analyzed by GC and GC-MS. A male-specific compound, zingiberenol, was identified in extracts from males, whereas a series of defensive compounds were identified in extracts from both sexes. Synthesis was undertaken for the zingiberenol that presents three chiral centers in the structure. The synthetic procedure produced two groups of material, zingiberenol-1 containing 4 isomers, namely (1RS,4RS,1'R)-4-(1',5'-dimethylhex-2'-enyl)-1-methylcyclohex-2-en-1-ol, and zingiberenol-2 containing 4 isomers, namely (1RS,4RS,1'S)-4-(1',5'-dimethylhex-2'-enyl)-1-methylcyclohex-2-en-1-ol. Bioassays carried out with the two groups of stereoisomers revealed that the group of zingiberenol-2, containing the diasteroisomers (1RS, 4RS, 1’S)-4-(1’, 5’-dimethylhex-4’-enyl)-1-methylcyclohex-2-en-1-ol was as attractive to females as the crude extract of male volatiles. The absolute configuration of the natural pheromone remains to be elucidated.