| Summary: | 博士 === 國立臺灣師範大學 === 生物研究所 === 87 === SEX PHEROMONES OF TEA PESTS:
ANDRACA BIPUNCTATA WALKER AND
EUPROCTIS PSEUDOCONSPERSA (STRAND)
ABSTRACT
Octadecanal, (E)-11-octadecenal, (E)-14-octadecenal and (E,E)-11,14-octadecadienal were isolated from the female pheromone gland of Andraca bipuncata in Taiwan. All four compounds were synthesized and bioassayed by electroantennography. Among these compounds, only (E,E)-11,14-octadecadienal could elicited big EAG response from male A. bipuncata. In the field test, only lures contained (E,E)-11,14-octadecadienal could catch male moths of A. bipuncata.
10,14-Dimethylpentadecyl isobutyrate was identified from extracts of pheromone glands of the female tea tussock moth, Euproctis pseudoconspersa (Strand) by gas chromatography in Taiwan. EAG records showed that (R)- and (S)-enantiomers and pheromone extract could cause male antennal responses. Crude pheromone extract elicited a larger EAG response than did (R)-10Me14Me-15:iBu, but the EAG response to the (S)-enantiomer was smaller than that to crude extract or the (R)- enantiomer. In field tests, the (R)-enantiomer showed better attractancy than did both the (S)-enantiomer and racemic mixtures in July 1998. However, later in the season, the (R)-enantiomer and racemic mixtures showed a similar attractancy, and both were better than the (S)-enantiomer. Traps baited with 20 μg of racemic mixtures and those with 2 virgin females showed similar attractancies, however, more males were caught with 80-μg baited traps.
The antennae of A. bipunctata are sexually dimorphic; those of males are pectinate with 43 pairs of branches, and those of females are filiform without branches. The antennae of both male and femae E. pseudoconspersa are pectinate, however, the one of the male is twice larger than the female''s. In both species, most sensilla are on the frontal (windward, ventral) side, and the types of sensilla differ in the 2 sexes. The main type of male A. bipunctata is sensillum trichodeum (s. trichodeum), but in females are s. basiconicum and the short s. chaeticum. In E. pseudoconspersa the main type of the male is long s. trichodeum, however, of the female is short s. trichodeum.
Each putative pheromone-sensitive s. trichodeum of A. bipunctata was innervated by 2 bipolar neurons enveloped by three sheath cells. The single sensillum recording of a s. tirchodium showed spikes of 2 different amplitudes after (E,E)-11,14-octadecadienal stimulation. This result indicated that s. trichodea were indeed the sex pheromone receptor.
|
|---|
