Generalist predators, increased plant density, and lower temperature reduce flea beetle (Coleoptera: Chrysomelidae) damage to canola (Brassicaceae) stems and cotyledons
Bibliographic record
Abstract
Abstract The crucifer flea beetle, Phyllotreta cruciferae (Goeze), and the striped flea beetle, P. striolata (Fabricius) (Coleoptera: Chrysomelidae), are invasive pests to canola, Brassica napus (Linnaeus) (Brassicaceae), in North America. Understanding how temperature and predators influence flea beetle damage in canola is critical for improving current management strategies, yet these factors are rarely studied. We examined the prevalence (proportion of plants damaged), intensity (defoliation of damaged plants), and overall damage (mean defoliation = prevalence × intensity) caused by flea beetles on canola seedlings at different temperatures, plant densities, and with or without generalist predators. Flea beetles preferred to feed on the abaxial (undersides) of cotyledons rather than the typically assessed adaxial (top) side, regardless of temperature, and produced more stem and cotyledon damage at higher temperatures, regardless of the species. Predators Pardosa spp. (Araneae: Lycosidae) and Pterostichus melanarius (Illiger) (Coleoptera: Carabidae) reduced flea beetle abundance and the intensity of cotyledon defoliation. Pterostichus melanarius also reduced overall stem damage, whereas Pardosa spp. reduced stem damage intensity. Under constant flea beetle densities, canola sustained less damage at a higher plant density. These results suggest that reducing the number of flea beetles per seedling, through predation or higher plant density, may help reduce Phyllotreta damage to canola.
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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) | 0.002 | 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".