Influence of Plant Host Quality on Fitness and Sex Ratio of the Wheat Stem Sawfly (Hymenoptera: Cephidae)
Bibliographic record
Abstract
Abstract A resurgence of the wheat stem sawfly, historically the most important pest of wheat in the northern Great Plains, has been observed in western Canada over the past decade. Host plant resistance in the form of solid-stemmed cultivars remains the primary management strategy for this pest. The objectives of this study were to determine the effects of wheat cultivar on wheat stem sawfly fitness and sex ratio. The cultivars studied varied with respect to stem diameter and pith expression and included representatives of the red seed, solid-stemmed spring and red seed, hollow-stemmed common and durum wheat classes. We present results from a primary study conducted in southern Alberta from 2001 to 2003 and a similar smaller study conducted in 1987 and 1991. All of the solid-stemmed cultivars (AC Eatonia, AC Abbey, Lancer, Leader) reduced female weights, size, fecundity, and in some cases, larval survivorship in the cut stubs and delayed date of adult emergence in the laboratory. Males were less responsive to this aspect of host quality. The hollow-stemmed durum cultivar AC Navigator had similar negative effects and deserves further study. A number of other hollow-stemmed wheats (McKenzie, AC Intrepid, Katepwa, and the durum AC Avonlea) had intermediate but inconsistent negative effects on sawfly fitness. The varieties that maximized sawfly fitness were AC Cadillac, CDC Teal, and Kyle (durum). Sawfly sex ratios were affected by stub diameter in our current and historical cultivar studies. Larger diameter stubs produced significantly more females and smaller diameter stubs produced more males. Furthermore, stubs that failed to produce adults had significantly smaller diameters than those that produced females but similar to those that produced males. The effect of the solid stem trait on sex ratio was inconsistent. Only Lancer had a male-biased sex ratio, whereas the other varieties had no consistent pattern. These results, however, are similar to other published reports that have noted inconsistent effects of the solid trait on sex ratio. Planting a solid-stemmed cultivar in a rotation that includes broad-leaved crops is recommended to reduce sawfly damage and future populations.
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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".