Monoterpene Emissions from Lodgepole and Jack Pine Bark Inoculated with Mountain Pine Beetle‐Associated Fungi

Abstract

Relative monoterpene levels were analyzed from bark samples of lodgepole pine, jack pine, and their hybrids inoculated with mountain pine beetle (MPB)–associated fungi (Leptographium longiclavatum, Grosmannia clavigera, and Ophiostoma montium). Lodgepole pine showed the largest changes in relative emissions as a result of fungal inoculation. The relative emission of β‐phellandrene increased with fungal inoculation, making it the most abundant monoterpene for inoculated samples. Relative emissions of limonene and α‐pinene decreased in inoculated lodgepole pine. Lodgepole (5.6) and jack (146) pine differed in the ratio of α‐pinene to myrcene; two monoterpenes involved in pheromone synthesis by the MPB. These differences may contribute to the attractiveness of the two species as hosts for MPB; with jack pine potentially less attractive than lodgepole pine. Fungal inoculation reduced α‐pinene:myrcene ratios in lodgepole pine, which suggests one possible mechanism by which the fungi benefit the beetle.