Test of Semiochemical Mediated Host Specificity in Four Species of Tree Killing Bark Beetles (Coleoptera: Scolytidae)
Bibliographic record
Abstract
We tested the hypothesis that nonhost conifers contain compounds that repel coniferophagous bark beetles (Coleoptera: Scolytidae) during host selection in four experiments (n = 10) involving paired trees baited with aggregation pheromones. Mountain pine beetles, Dendroctonus ponderosae Hopkins, and Douglas-fir beetles, Dendroctonus pseudotsugae Hopkins, were tested for discrimination between their respective hosts, lodgepole pine and Douglas-fir, and spruce beetles, Dendroctonus rufipennis Kirby, and western balsam bark beetles, Dryocoetes confusus Swaine, for discrimination between interior spruce and interior fir. Both host and nonhost conifers in a pair were baited with the same aggregation pheromone. Most baited host trees were successfully attacked and contained galleries with eggs or young larvae. Neither D. rufipennis nor D. confusus attempted to establish galleries on nonhosts. A few attacks were initiated on nonhosts by D. pseudotsugae and D. ponderosae, but most did not reach the phloem tissue, and in no case were they numerous enough to have produced a significant source of aggregation pheromone. Thus employing pheromone-baited nonhost trap trees would not be an effective management tactic. Higher trap catches in unbaited multiple funnel traps within 1 m of nonhost trees than in control traps 12.5 m away also indicated that there was no strong long range repellence caused by nonhost volatiles. Although this study was not designed to evaluate primary attraction to host trees, the lack of strong repellence from nonhost conifers partly supports the hypothesis of random landing followed by close range olfactory or gustatory rejection of nonhosts.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".