Higher human population density is shaded
In Colorado, field research is done with Ips pini and Dendroctonus ponderosae (the mountain pine beetle) attacking ponderosa
pine (Pinus ponderosa) and lodgepole pine (P. contorta). The research is in cooperation with Göran Birgersson, Dept. of Chemical Ecology, Göteborgs University, and
with Anna-Karin Borg-Karlsson, Dept. of Organic Chemistry, Royal Institute of Technology, Stockholm. Other, research is done on ants (Lasius,
Formica and harvester ants in regard to nest temperatures. Insect sounds are also recorded with the idea of
Field research is also conducted in the Sierra Nevada mountains of California at Bass Lake near Yosemite National Park.
In this region it never rains in the the summer (almost never)
and bark beetles, mainly Ips paraconfusus and Dendroctonus brevicomis (western pine beetle), are active all summer long.
I. paraconfusus feeds on allmost all native pine species, including
ponderosa and lodgepole pines (mentioned above); Pinus sabiniana (digger pine); P. lambertiana (sugar pine);
and P. jeffreyi (Jeffrey pine). D. brevicomis only feeds on two pine species, ponderosa pine and
Coulter pine, however, ponderosa pine is very much more common in California. I have not
done research in California for about 5 years, but have collected resin samples from several pine species. We
are interested in resin monoterpenes since these compounds (e.g. myrcene, alpha-pinene, beta-pinene,
limonene, 3-carene) can be precursors to pheromone components of bark beetles or may be somewhat toxic
to the beetles (they are highly toxic to other insects not adapted to confers).
For more information:
Competition between Ips paraconfusus and D. brevicomis
Females tell males to stop making pheromone
Antibiotic inhibits male bark beetle pheromone production
Male bark beetles avoid strong male pheromone (to avoid competition)
Which pheromones regulate western pine beetle attack of ponderosa pine
Five host pines of and pheromone precursors
© 1997 by John Byers