Survival of elongate hemlock scale (Hemiptera: Diaspididae) with prolonged cold exposure: overwintering mortality risk across North America
Bibliographic record
Abstract
Elongate hemlock scale, Fiorinia externa Ferris (Hemiptera: Diaspididae), is an invasive pest of eastern hemlock, Tsuga canadensis, and other Pinaceae such as Fraser fir, Abies fraseri. Cut Fraser firs (ie for Christmas trees and other holiday greenery) with F. externa have been intercepted in US states beyond where the insect is known to be established and, in some cases, where exposure to freezing temperatures might be prolonged. This study measures the effect of constant low temperatures (3, -10, or -20 °C) on survival of overwintering F. externa females from eastern hemlock in Michigan and from eastern hemlock and Fraser fir in North Carolina. Survival was determined with biochemical viability testing, which assesses the presence of metabolically active cells, and changes in survivorship through time were quantified with Kaplan-Meier methods and beta regression. Collection date and host occasionally affected survival rate but not in a consistent pattern. Survival rates generally decreased as temperature decreased. At 3 °C, F. externa maintained high survival (>75%). At -10 °C, survival was projected to fall to 50% within 22 to 92 d and 10% by 45 to 195 d. At -20 °C, survival typically declined to 50% by 1 to 27 d and 10% by 6 to 52 d. We used survival durations at -20 °C to map how often F. externa might experience 50 or 90% mortality from prolonged cold exposure. Temperatures in recent winters have not been below -20 °C for long enough to stop F. externa from spreading throughout the ranges of eastern hemlock or other hosts in Canada and the continental United States.
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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".