Sex pheromone of the oleander scale, Aspidiotus nerii: structural characterization and absolute configuration of an unusual functionalized cyclobutane.

The sex pheromone emitted by the female oleander scale, Aspidiotus nerii (Homoptera, Diaspididae), has been isolated and characterized as (1R, 2S)-cis-2-isopropenyl-1-(4'-methyl-4'-penten-1'-yl)cyclobutaneethanol acetate by using advanced MS and NMR spectroscopic methods, as well as a variety of microderivatization sequences. The structure has been confirmed by stereo- and enantioselective synthesis of the four possible stereoisomers. The absolute configuration has been determined by comparison of the activity of the cis (1S,2R) and (1R, 2S) enantiomers with that exhibited by the natural material in greenhouse bioassays and field tests. The structure of this sesquiterpenoid pheromone is new in the coccids and in the pheromone field in general.

Chemical identification, electrophysiological and behavioral activities of the pheromone of Metamasius hemipterus (Coleoptera: Curculionidae).

Five hydroxylated aliphatic molecules were identified as the pheromone produced by male West Indian Sugarcane Borer (WISB): 4-methyl-5-nonanol (1), 2-methyl-4-heptanol (2), 2-methyl-4-octanol (3), 5-nonanol (4) and 3-hydroxy-4-methyl-5-nonanone (5). Electroantennographic recordings revealed antennal responses to compounds 1, 2, 3 and 4. Significant EAGs were also recorded in response to pheromone compounds of weevils belonging to the same subfamily and structurally related to the WISB pheromone. The natural pheromone elicited aggregation behavior on WISB adults in laboratory bioassays.

Dorsal abdominal glands in nymphs of southern green stink bug,Nezara viridula (L.) (heteroptera: Pentatomidae): Chemistry of secretions of five instars and role of (E)-4-oxo-2-decenal, compound specific to first instars.

We investigated the exocrine secretions from the five nymphal instars in the southern green stink bug,Nezara viridula, by analyzing separately the contents of the three dorsal abdominal reservoirs. All DAGs 1 produced a mixture of five alkanes with 12, 13, 14, 15, and 16 carbons. No differences were found between DAGs 2 and DAGs 3, for the five instars: the glands of first instars produce the same alkanes as DAGs 1,n-tridecane, traces of (E)-2-decenal, and a specific compound: (E)-4-oxo-2-decenal. In the other instars (second to fifth), (E)-4-oxo-2-decenal is absent from the secretion but another compound is present: (E)-4-oxo-2-hexenal. The kinetics of production of the different compounds were studied, the maximum amounts produced occurring 36 hr after hatching. The biological function of (E)-4-oxo-2-decenal was investigated. Using olfactometry, we showed that this compound acts as an attractant and an arrestant on second instars, at physiological doses. Moreover, this semiochemical was shown to be repellent to the fire-antSolenopsis geminata, a potential predator ofN. viridula and we established the dose-response curve for the repellent activity.

Defensive secretion of first-instar larvae of rootstalk borer weevil,Diaprepes abbreviatus L. (Coleoptera: Curculionidae), to the fire-antSolenopsis geminata (F.) (Hymenoptera: Formicidae).

Since several species of predatory ants show some kind of repulsion towards the first-instar larvae (FIL) ofDiaprepes abbreviatus L., the predatory behavior ofSolenopsis geminata (F.), a common ant in the citrus groves in Guadeloupe, was studied. Different extracts of larvae were disposed on egg masses ofD. abbreviatus and presented as prey to the ants, both in the field and in the laboratory. The ants are repelled by the FIL extracts. The allelochemicals involved are produced in large amounts, from 5 to 20 ng per larva. Physiochemical analyses have led to the identification of two sesquiterpenes of molecular weight 218 and 234, secreted in the respective proportions of 65 and 35%.

Male-produced aggregation pheromone of the american palm weevil,Rhynchophorus palmarum (L.) (Coleoptera, Curculionidae): Collection, identification, electrophysiogical activity, and laboratory bioassay.

Male American palm weevils (APWs),Rhynchophorus palmarum (L.) produced two sex-specific compounds, which were disclosed by volatile collections on Supelpak-2 and gas chromatography. One was a minor compound, not always detected. The major male-produced volatile was identified as (2E)-6-methyl-2-hepten-4-ol through coupled gas chromatography-mass spectrometry and gas chromatography-Fourier transform infrared spectrometry, proton nuclear magnetic resonance spectrometry, and rational synthesis. We propose the trivial name rhynchophorol for this new molecule, which proved to be the essential component of the APW aggregation pheromone by electroantennography, coupled gas chromatography-electroantennography and behavioral bioassays.