Identification of pheromone components of Plagionotus detri-tus

The
longhorn beetle Plagionotus detritus (L.)
occurs from Europe to the Middle East. Our principal aim was to identify the male-produced
aggregation-sex attractant pheromone of this species. A pheromone-based
monitoring system could support plant protection in areas where it might become
a pest, and natural conservation in areas where it is endangered. Headspace volatiles were collected
from live beetles and analyzed by coupled gas chromatography-electroantennogram
detection, and gas chromatography-mass spectrometry. Two components of the
extracts that elicited responses from antennae of P. detritus, (R)-3-hydroxyhexan-2-one
and (S)-2-hydroxyoctan-3-one were identified, synthesized, and field
tested. The blend of the two components attracted both sexes of P. detritus in field bioassays, and a predatory clerid beetle, Clerus mutillarius F., was attracted by
both compounds. Another longhorn beetle species, Xylotrechus antilope Schönh. was significantly attracted to traps baited with (S)-2-hydroxyoctan-3-one alone or the blend containing this
compound. These results show that the pheromone components and blends play key
roles in longhorn beetle life history and ecology, and the community of species
with which they live.