Abstract Detail

Ecology

Madden, Julie [1], Keefover-Ring, Ken [2], Duran, Kristy [3].

Correlation between dwarf mistletoe infection and monoterpene concentrations in Pinus Ponderosa.

The rapid decline of conifers throughout the world has resulted from various parasitic species such as the bark beetles and dwarf mistletoe. In an effort to combat the attacks of these species, conifers have developed various host defenses including the production of allelochemicals. There has been an increasing amount of interest surrounding one class of these chemicals known as monoterpenes, because of their potential to affect the behavior and reproduction of parasitic species. One monoterpene, limonene has been shown to deter female bark beetles. On the other hand beta-pinene has been shown to be attractive to a number of bark beetle speices. Conifers are also susceptible to infection by dwarf mistletoe. It is possible that a correlation between mistletoe infection and monoterpene production may affect subsequent bark beetle attack. This study examines whether such correlation exists. Southwest dwarf mistletoe (Arceuthobium vaginatum) is a hemiparasitic plant that primarily infects ponderosa pines (Pinus ponderosa) and has played a major role in reshaping the forest landscape of Colorado. In an effort to determine if the levels of monoterpenes varied in ponderosa pines infected with southwest dwarf mistletoe, gas chromatography coupled with a flame ionization detector (GC-FID) was employed. Samples were collected from the Zapata Subdivision in Alamosa, Colorado within a one hectare area. The samples consisted of pine needles, in which ten samples were taken from trees that were not infected with mistletoe and ten from trees infected with mistletoe. Various monoterpenes were extracted from the needle tissue with hexane and a quantitative analysis conducted using GC-FID. Total monoterpene concentrations were significantly higher in uninfected trees compared to infected trees (p = 0.017). Both limonene and (-) beta-pinene concentrations were significantly higher in uninfected than in infected trees (p = 0.002 and 0.021 respectively). Bark beetles respond differently to these two monoterpenes suggesting that infected trees may be more susceptible to bark beetle infection because of lower limonene concentrations. On the other hand, bark beetles may be more attracted to uninfected trees because of higher (-) beta-pinene concentrations. Therefore, trees infected with dwarf mistletoe and those not infected may be equally susceptible to infection by bark beetles.

1 - Adams State University, Chemistry
2 - University of Wisconsin-Madison, Department of Entomology
3 - Adams State University, Biology and Earth Science, 208 Edgemont Blvd, Alamosa, Colorado, 81101, USA

Keywords:
Dwarf mistletoe
Ponderosa pine
Pinus ponderosa
Monoterpenes
defense
bark beetles.

Presentation Type: Poster
Session: P, Ecology Section Posters
Location: Exhibit Hall/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 5:30 PM This poster will be presented at 6:15 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PEC034
Abstract ID:790
Candidate for Awards:None