Schlyter, F., Löfqvist, J. & Byers, J.A. 1987b. Behavioural
sequence in attraction of the bark beetle Ips typogra-
phus to pheromone sources. Physiological Entomology
12:185-196.
Abstract--
The functions of the two synergistic pheromone components,
(4S)-cis-verbenol (cV) and 2-methyl-3-buten-2-ol (MB), and the role of
ipsdienol in the attraction of Ips typographus (L.) (Scolytidae) to
pheromone sources were studied in the field. Absolute and relative
beetle catches were compared between several traps placed at and
nearby a central pheromone source: a pipe trap containing the source,
a surrounding sticky trap, a nearby window trap, and four distinct
window traps. A higher catch in the outer down-wind distant traps
indicated an up-wind anemotaxis to the source. Increased MB release,
with cV constant, increased the proportion caught in the central pipe
trap, indicating MB as a landing stimulus. Release of MB alone gave a
very small catch. Ipsdienol could not substitute for cV in the
synergism with MB. An increase of cV, with MB constant, increased the
number of beetles caught, but not the proportion caught in the pipe
trap. The sex ratio was equal in the window traps, but fell to 30%
males in both sticky and pipe traps, showing that a large proportion
of the males attracted to the source did not land. The proportion of
males in the pipe trap was reduced at the highest cV dose. The
results support the idea of each pheromone component having a
different relative importance in releasing different steps in the
behavioural chain.
Chemical Ecology