Journal of Chemical Ecology (1998) 24, 321-337

Anne Savoie, John H. Borden, Harold D. Pierce Jr., Regine Gries and Gerhard Gires (1998)
Aggregation pheromone of Pityogenes knechteli and semiochemical-based interactions with three other bark beetles
Journal of Chemical Ecology 24 (2), 321-337
Abstract: Gas chromatographic-electroantennographic detection and GC-mass spectrometric analyses of volatile extracts from male and female Pityogenes knechteli Swaine identified hexanol, (±)-ipsdienol, and (S)-(-)-ipsenol as male-produced candidate pheromone components. In a lodgepole pine, Pinus contorta var. latifolia Engelmann, forest in the southern interior of British Columbia, multiple-funnel traps baited with (±)-ipsdienol alone, (S)-(-)-ipsenol alone, or both caught 60%, 6%, and 23%, respectively, of all P. knechteli trapped; unbaited traps caught the remaining 11%. In another field trapping experiment, (S)-(+)-ipsdienol was as attractive as (±)-ipsdienol, and (R)-(-)-ipsdienol was behaviorally benign. (S)-(+)-Ipsdienol is thus concluded to be the principal aggregation pheromone component of P. knechteli. At low release rates, hexanol increased attraction of beetles to (±)-ipsdienol, or to (±)-ipsidienol plus (S)-(-)-ipsenol, but at high release rates hexanol decreased attraction, suggesting a role in preventing overpopulation in the host tree. On the basis of laboratory bioassays in which walking beetles were attracted to (S)-(-)-ipsenol, we hypothesize that (S)-(-)-ipsenol serves as a short-range attractant for P. knechteli. Three sympatric scolytids were also captured in field experiments as follows: the pine engraver, Ips pini (Say), to its pheromone (±)-ipsdienol; I. latidens LeConte to its pheromone (S)-(-)-ipsenol; and I. mexicanus (Hopkins), for which the pheromone is unknown, to (S)-(-)-ipsenol with (±)-ipsdienol. Although all four species attack lodgepole pine, we have never observed I. latidens or I. mexicanus attacking the same hosts at P. knechteli or I. pini. These results suggest that ipsenol and ipsdienol serve as synomones involved in promoting aggregation on the host tree, maintaining species-specific communication, and thus contributing to resource partitioning and reduced competition among the four species.
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Link to article at publishers website
Database assignments for author(s): John H. Borden

Research topic(s) for pests/diseases/weeds:
pheromones/attractants/traps

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Ips pini	Pine (Pinus)	Canada (west)
	Pityogenes knechteli	Pine (Pinus)	Canada (west)
	Ips latidens	Pine (Pinus)	Canada (west)
	Pseudips mexicanus	Pine (Pinus)	Canada (west)