Population Structure of the Cabbage Seedpod Weevil,<i>Ceutorhynchus obstrictus</i>(Marsham) (Coleoptera Curculionidae): Origins of North American Introductions
Bibliographic record
Abstract
Determining the origins of invasive species has important management implications when introduced species become pests, especially when candidate biocontrol agents are specialized on host biotypes. The cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham), is a European native that was first discovered in North America in British Columbia in 1931. It has since become a major economic pest of brassicaceous oilseed crops. To assess population structure and determine points of origin for North American introductions, we sequenced a 475-bp fragment of the mitochondrial DNA COI gene in 176 individuals from 16 localities from North America and Europe. Eleven haplotypes were found, with one haplotype present in every locality and represented by 71% of all individuals. Nested clade analysis indicated fragmentation, range expansion, restricted gene flow, and long distance dispersal. Analysis of molecular variance (AMOVA) also showed significant population structure and supported an inference of restricted gene flow between populations. These patterns may be explained by two separate introductions to North America. The first introduction was to western North America from source locations likely to have been western or northern Europe, and the second was to northeastern North America from locations, such as Sweden or Russia, that are distinct from the first introduction. At least two females were introduced to western North America, and three to northeastern North America, where the species was recently detected in Quebec.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 teacher head, 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".