The objectives undertaken in this study were:
1) to develop means of identifying the immature stages of
the known insect predators and parasites of the Douglas-fir beetle; 2) to investigate the possible distribution,
spatially and/or temporal, of the known insect predators
and parasites in standing trees infested by the Douglas-fir...
The effect of competition on the brood survival of the Douglas fir
beetle Dendroctonus pseudotsugae Hopkins, in down or windthrown
Douglas-fir Pseudotsuga menziesii (Mirb.) Franco was studied in the
field and the laboratory. The investigation of the role of competition
in the population dynamics of the beetle had four objectives:...
Three coleopterous predators associated with the Douglas-fir
beetle (Dendroctonus pseudotsugae Hopkins in a second growth
forest of Douglas-fir (Pseudotsugae menziesii (Mirb. ) Franco)
in western Oregon are Enoclerus sphegeus Fabriciup, E, lecontei
Wolcott, and Thanasirnus undatulus Say. A study was undertaken
with the following objectives: (1) to determine the diurnal...
Three sympatric species of Ips, colonizing Sitka spruce, were
investigated with regard to their infestation habits, stridulating
apparatus and acoustic signals. The above phenomena are evaluated
qualitatively and/or quantitatively and the acoustic signal differences
are proposed as a possible factor for maintaining species isolation,
although function is not shown.
Field...
Both Leperisinus oregonus and L. californicus are bark beetle
species which emerge from Fraxinus latifolia brood logs as sexually
immature adults and disperse to living ash. Occasional field observations suggest that, for overwintering and maturation feeding, L.
oregonus enter trunks and branches, whereas L.; californicus enter twig
crotches, buds and...
The study was undertaken to determine the seasonal and diurnal
flight patterns of scolytid beetles inhabiting a second growth
forest of Douglas-fir (Pseudotsuga menziesii (Mirb.)Franco) in western
Oregon. Air temperatures, relative humidity, light intensity, and wind
velocities were recorded for evaluation of their influence on flight activity.
The insects were...