Increase of trap catches by a combination of male sex pheromones and floral attractant in longhorn beetle, Alaglyptus subfasciatus (Coleoptera: Cerambycidae)

K. Nakamuta 1 , T. Gotoh 2 , M. Tokoro 1 & T. Nakashima 1

1 Forest Biol. Div., Forestry & Forest Prod. Res. Inst. (FFPRI), P. O. Box 16, Tsukuba Norin Kenkyu Danchi-nai, 305-8687, Tsukuba, Japan; 2 Tohoku Res. Center, FFPRI, Nabeyashiki 72, Shimokuriyagawa, Morioka, 020-0123, Japan

Anaglyptus subfasciatus (Coleoptera: Cerambycidae) is one of the most harmful insect pests of the Japanese cedar, Cryptomeria japonica, and the Japanese cypress, Chamaecyparis obtusa, the most abundant tree species of forest plantations in Japan. Females of the beetles lay their eggs on the dead twigs of the cedar or the cypress and the larvae bore into the twigs and migrate further into the tree trunk. Feeding by the larvae on sapwood followed by fungal infection causes discoloration and decay of the wood, resulting in a decrease of the commercial value of timbers. Since A. subfasciatus males and females were known to congregate on several species of flowers for feeding, floral scents and their structural similarities have been screened both in the laboratory and in the field. Methyl phenylacetate has been demonstrated as the most attractive and highly specific to A. subfasciatus and has been used as the most reliable floral attractant for A. subfasciatus in practice. A. subfasciatus females were attracted to males in a wind tunnel and that a male-specific cuticular structure in the pronotum seems to be an organ of pheromone excretion. Furthermore, the male-released sex pheromone constituents of the beetle are identified as a 7:1 blend of (R)-3-hydroxy-2-hexanone and (R)-3-hydroxy-2-octanone. We have observed that the beetles were attracted to the trap baited with floral attractant alone, but they walked around the tree trunks or logs near the trap. Therefore we tested whether a combination of male sex pheromone constituents and the floral attractant improved pinpoint location of the beetles and increased the trap catches. In the present paper we report that the trap catches of the female beetles were increased by a combination of male sex pheromone constituents and the floral attractant.

Index terms: attraction, Methyl phenylacetate, (R)-3-hydroxy-2-hexanone, (R)-3-hydroxy-2- octanone

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