Comparison of lodgepole and jack pine resin chemistry: implications for range expansion by the mountain pine beetle,Dendroctonus ponderosae(Coleoptera: Curculionidae)

Abstract

The mountain pine beetle, Dendroctonus ponderosae, is a significant pest of lodgepole pine in British Columbia (BC), where it has recently reached an unprecedented outbreak level. Although it is native to western North America, the beetle can now be viewed as a native invasive because for the first time in recorded history it has begun to reproduce in native jack pine stands within the North American boreal forest. The ability of jack pine trees to defend themselves against mass attack and their suitability for brood success will play a major role in the success of this insect in a putatively new geographic range and host. Lodgepole and jack pine were sampled along a transect extending from the beetle’s historic range (central BC) to the newly invaded area east of the Rocky Mountains in north-central Alberta (AB) in Canada for constitutive phloem resin terpene levels. In addition, two populations of lodgepole pine (BC) and one population of jack pine (AB) were sampled for levels of induced phloem terpenes. Phloem resin terpenes were identified and quantified using gas chromatography. Significant differences were found in constitutive levels of terpenes between the two species of pine. Constitutive α-pinene levels – a precursor in the biosynthesis of components of the aggregation and antiaggregation pheromones of mountain pine beetle – were significantly higher in jack pine. However, lower constitutive levels of compounds known to be toxic to bark beetles, e.g., 3-carene, in jack pine suggests that this species could be poorly defended. Differences in wounding-induced responses for phloem accumulation of five major terpenes were found between the two populations of lodgepole pine and between lodgepole and jack pine. The mountain pine beetle will face a different constitutive and induced phloem resin terpene environment when locating and colonizing jack pine in its new geographic range, and this may play a significant role in the ability of the insect to persist in this new host.

The Effect of Water Limitation on Volatile Emission, Tree Defense Response, and Brood Success of Dendroctonus ponderosae in Two Pine Hosts, Lodgepole, and Jack Pine

“…In this, and many other studies, α-pinene is the most abundant monoterpene in jack pine phloem, but its enantiomeric composition has rarely been measured. Our results show that jack pine phloem contains only half the amount of (−)-α-pinene per unit of phloem tissue compared to lodgepole pine, which is in accordance with the findings of Clark et al (2014). Nonetheless, in laboratory experiments, MPB females emit twice the amount of (−)-trans-verbenol when tunneling in jack pine bolts compared to lodgepole pine (Erbilgin et al, 2014).…”

Host location and selection of lodgepole pine (Pinus contorta) by the Warren root collar weevil (Hylobius warrei ).

“…Further, the seedlings used in this study appeared to be predominantly the (+) enantiomer of (1-pinene, rather than the (-) form. This is in contrast to the results of Pureswaran et al (2004), who found that the (-) enantiomer was more abundant in both the bole woody tissue (bark, phloem and sapwood) and foliage of mature trees, and the results of Clark et al (2014) who found only the (-) enantiomer and none of the (+) enantiomer in the phloem tissue of mature trees. Possibly the differences observed between this study and previous work, in these final two terpenes, could be due to using seedlings instead of mature trees or using branches instead of woody tissue from the bole of the tree, as previous studies have suggested that monoterpene compositions can vary between different tissues within the same tree (Pureswaran and Borden 2004 and references within).…”

“…These results are similar to those of Pureswaran et al (2004), who found similar trends of camphene and sabinene, and to those of Clark et al (2014) who found similar trends for a-pinene in lodgepole pine woody tissue. In addition, the (-) enantiomer of a-pinene is the form of the molecule that is converted to the biologically active enantiomer of the pheromone (-) trans-verbenol by MPB females (Borden et al 1987).…”

“…There was no significant difference between the (+) and (-) forms of limonene in the seedlings analyzed in this study. Conversely, previous work on mature trees has suggested that the (-) enantiomer of limonene may tend to be more prevalent than the (+) form (Pureswaran et al 2004, Clark et al 2014. Further, the seedlings used in this study appeared to be predominantly the (+) enantiomer of (1-pinene, rather than the (-) form.…”

Population dynamics and epidemiology of four species ofDendroctonus(Coleoptera: Curculionidae): 100 years since J.M. Swaine

“…However, lack of knowledge regarding altered trophic interactions in novel habitats precluded the capacity to predict the rate of spread and subsequent impacts of the invading population. This point is particularly relevant since new evidence suggests that the defensive response (Clark et al 2010(Clark et al , 2014, the ability of beetles to aggregate (Burke and Carroll 2016), and the ultimate productivity of the mountain pine beetle (Cudmore et al 2010), in putatively "evolutionarily naïve" trees may be very different from expectations derived from the beetle's historic habitat.…”