Mountain pine beetle
| Mountain pine beetle | ||||||||||||
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Mountain pine beetle ( Dendroctonus ponderosae ) |
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| Dendroctonus ponderosae | ||||||||||||
| Hopkins , 1902 |
The mountain pine beetle ( Dendroctonus ponderosae , English "Mountain pine beetle" ) is a bark beetle that lives in the forests of North America .
features
The beetle is black, has a cylindrical shape and a length of 4 to 7.5 mm. The legless larvae are creamy white with a light brown head capsule and reach a length of 6 to 7 mm in the last larval stage. The eggs are white, oval and translucent.
distribution and habitat
The mountain pine beetle is found in Canada , the USA and Mexico . It lives in forests with yellow pine ( Pinus ponderosa ) and coastal pine ( P. contorta ). But also the white-stemmed pine ( P. albicaulis ), the Rocky Mountain Intermountain subspecies of the coastal pine ( P. contorta subsp. Latifolia ), the sugar pine ( P. lambertiana ), the western Weymouth pine ( P. monticola ) and the species of black pine ( P. nigra ) and Scots pine ( P. sylvestris ) introduced in North America offer it a habitat. Also on other pine species such as B. Awn pine ( P. aristata ), Foxtail pine ( P. balfouriana ), Coulter pine ( P. coulteri ), Pinus edulis , flexible pine ( P. flexilis ) and single-leaved pine ( P. monophylla ) has been found been.
Douglas fir ( Pseudotsuga menziesii ), incense cedar ( Calocedrus decurrens ), firs ( Abies spp. ), Larches ( Larix spp. ) And spruces ( Picea spp. ) - here in particular the Engelmann spruce ( Picea engelmannii ) - are also occasionally attacked, especially near pines, but are not suitable for the reproduction of the beetle.
Way of life
The mountain pine beetle inhabits pines , especially the yellow pine and coastal pine . In the early stages of distribution, the population is still concentrated on sick, old, unfavorably positioned or otherwise damaged trees. Over time, however, healthy trees will also be attacked. The infestation usually begins with pioneer females, who send out pheromones after the tree is infested , which attracts males in large numbers.
The beetles kill the trees by drilling a hole through the bark up to the phloem layer. The animals feed on this nutrient-rich layer and lay their eggs there. The trees react to the infestation by increasing resin production , which, however, comes to a standstill due to a fungus introduced with the beetle. After about two weeks, the phloem layer is so badly damaged that the tree loses its ability to transport water and nutrients, causing the tree to starve.
Individual evidence
- ↑ a b c Dendroctonus ponderosae - Information on the species from the FAO (accessed October 13, 2011).
Web links
- Fight between beetles and trees - report on Deutschlandfunk about the rampant pine beetle epidemic in Canada on April 18, 2006
- Attack of the beetles ( memento from January 5, 2008 in the Internet Archive ) - report of the ZDF foreign journal from September 13, 2007
- Bark beetles sabotage climate protection Frankfurter Allgemeine April 27, 2008
- Ministry of Forest and Range / British Columbia updated information on problems with the mountain pine beetle in Western Canada (in English)
- waldwissen.net : Bark beetle threatens pine forests in Canada