INVESTIGATING POPULATION DYNAMICS OF THE WHEAT STEM SAWFLY (CEPHUS CINCTUS) (HYMENOTERA: CEPHIDAE) IN CANADIAN AGROECOSYSTEMS
Bibliographic record
Abstract
The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), has been a serious economic threat to wheat production in the northwest Great Plains region of North America for over 100 years. Despite immense research efforts on C. cinctus population dynamics, there remain knowledge gaps. The objectives of this research were to determine how winter and early spring abiotic factors influence: 1) C. cinctus larval mortality and the spatiotemporal variation in the efficacy of larval mortality factors, and 2) adult life history traits of C. cinctus and one of its natural enemies, Bracon cephi Gahan (Hymenoptera: Braconidae). Post-harvest samples were collected from fields in southern Alberta to set baselines for the occurrence of live C. cinctus and larval mortality due to parasitism, fungal infection, and unknown reasons. Fields were re-visited the following spring (once in 2020 and twice in 2021) to measure changes in C. cinctus larval populations. We observed that the number of viable (i.e., living) C. cinctus larvae changed significantly between geographic sites but not over time. This conclusion highlights that overwintering and early season abiotic conditions are unlikely to affect C. cinctus population dynamics. The field-level variation underscores the importance of scouting individual fields if high C. cinctus population densities are expected in a given area. Laboratory experiments were conducted to test the effects of cold temperatures in early spring, that are known to prolong post-diapause development, on adult life history traits (e.g., longevity, body size, lipid content, and egg capacity) of C. cinctus and B. cephi. For C. cinctus, adult longevity and male lipid content significantly decreased when post-diapause development was extended. In contrast, neither B. cephi adult longevity nor body size were affected by the prolonged post-diapause development periods. These results provide novel information on how the post-diapause biology of two important native hymenopterans differ in response to temperature. Altogether, this research shows that while post-diapause abiotic conditions may not increase C. cinctus mortality, cold temperatures that delay C. cinctus adult emergence can greatly impact several adult life history traits that could impact population dynamics. This information will be useful for the development of C. cinctus phenology and population forecasting models.
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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 | 0.001 |
| 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".