|Dendroctonus brevicomis |
common name Western Pine Beetle
Living trees in conifer forests throughout its range.
Flight period is from early May through June. This may be extended if conditions remain warm.
Declivity is moderately steep, pubescent and has weak, granulate punctures on the interstriae. Depressions are found on the declivity between the first and third striae. The frons has a median groove that extends from the epistomal process to the upper level of the eyes. Usually very dark brown and between 2.0 and 4.7 mm. Closest ally is D. frontalis Zimmermann.
Overwintering adults become active in the spring as the local weather begins to warm. The female will find an appropriate host and will begin to attack the hard bark of the tree. The female will then be joined by the male and mating will occur. This species is polygynous so many females can be found in one gallery. Galleries can be large and may overlap upon itself. Oviposition occurs 8 days after mating and will last for 10 to 49 days, if interrupted by winter oviposition will continue in the spring. Up to 41 million eggs can be found in one gallery. After about 7 days the eggs will hatch and the larvae will mine the phloem for between 30 and 35 days, if winter interrupts the life cycle it will overwinter as a pre-pupae. The larvae pupates for 6 to 20 days and will remain within the gallery for 1 to 2 weeks after emergence before it leaves the tree. This species can have between 1.5 to 4 generations per year, depending on local weather conditions.
This species is considered a major forest pest, especially in Ponderosa pine forests.
Larvae feed on Pinus ponderosa and P. coulteri. During outbreaks it may feed on other Pinus species.
This species is found in pine forests in British Columbia in Canada. There are no records for this species in Alberta. This species is also found in the pine forests of the western USA in Washington, Idaho, Montana, Oregon, California, Utah, Nevada, Arizona, Colorado and New Mexico and as far south as Chihuahua in Mexico.
|species page author||Jensen, D.||2003 |
|species page editor||Shpeley, D.||2004 |