Schlyter, F., Birgersson, G., Byers, J.A., Löfqvist, J. &
Bergström, G. 1987c. Field response of the spruce bark
beetle, Ips typographus, to aggregation pheromone
candidates. Journal of Chemical Ecology 13:701-716.
Six compounds previously identified from hindguts of unmated male Ips
typographus (L.) during host colonization: 2-methyl-3-buten-2-ol (MB),
cis-verbenol (cV), trans-verbenol (tV), myrtenol (Mt),
trans-myrtanol (tM), and 2-phenylethanol (PE), were tested for their
attractivity in the field with a subtractive method. The amounts of
MB and cV released from a pipe trap were similar to those given off
from the commercial bait Ipslure as well as that from a Norway spruce
tree, Picea abies (L.) Karst., under mass attack. The blend of the
compounds became nonattractive when either MB or cV was subtracted,
while subtraction of any of the other four compounds had no effect.
Addition of ipsdienol (Id) to the blend did not significantly
increase the attraction. In a second comparative test, the addition
of three compounds as a group (tV + Mt + PE) to MB + cV again had no
effect on the attraction, but the addition of Id increased the catch
somewhat. Addition of host logs to a bait releasing MB + cV at a rate
lower than in previous experiments did not influence the attraction
to pipe traps. Sticky traps containing natural pheromone sources (50
males in a log), which released 1-5 mg/day of MB as determined by
aerations with deuterated MB as internal standard, were less
attractive than a synthetic source releasing similar amounts of MB.