Preliminary Assessment of the Cold Tolerance of Laricobius nigrinus, a Winter-active Predator of the Hemlock Woolly Adelgid from Western Canada
Bibliographic record
Abstract
respectively. Newly eclosed first instar larvae (L1) that had not yet begun to feed, supercooled to -24 °C, while their supercooling capacity both diminished slightly (0 = -22.1 °C) once feeding was intitated. Supercooling capacity diminished with each successive instar, with the SCPs of the L 2 , L 3 and L 4 being -17 oC, -15 oC and -13 oC respectively. Survival of eggs and adults after exposure to sub-zero temperatures above their mean SCPs (-10 oC and -20 oC for eggs; -10 oC and -15 oC for adults) for increasing durations (to a maximum of 8 h) was also evaluated. Survivorship was highest for eggs and adults exposed to -10 oC. Survival of eggs declined with decreasing temperature and increasing duration of exposure. Survival of eggs exposed to -20 oC for 1h was 45%, with no survival evident at longer durations. Increasing durations of exposure of adults to -15 oC (1 o -4 oC above mean adult SCPs) resulted in reduced adult survival. However, 40% of the adults tested survived 8h exposure to -15 oC. These results indicate that both the duration and extent of extreme winter minima may be determinants of the range of L. nigrinus in eastern North America. Laricobius nigrinus Fender is a winter active predator of the hemlock woolly adelgid (HWA), Adelges tusgae Annand, native to the Pacific northwest of North America. Adults appear in the foliage of infested hemlocks as the overwintering HWA sistens generation develops (Oct. Dec.) and begin oviposition in the ovisacs of HWA soon after adelgid oviposition begins in January. Thus, multiple life stages of the predator are present during the coldest periods of the Pacific Northwest winter. As L. nigrinus is being evaluated as a biological control agent against HWA in the eastern U.S., where winter climates can be more severe than those of its native range, it is important to understand the cold tolerance of the life stages of the predator present during the winter months. We assessed the cold tolerance of adults, eggs and larvae of L. nigrinus through evaluations of the supercooling points (SCPs) of field-collected adults and laboratory reared (at 5 °C) eggs and larvae. Freezing was fatal to all life stages. The mean SCPs of adults ranged between -16 oC and -19 oC, while those of overwintering one day and five day old eggs were -27.5 °C and -26.9 °C,
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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 | 0.001 | 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".