The direction, timing and demography of Popillia japonica (Coleoptera) invasion reconstructed using complete mitochondrial genomes
Bibliographic record
Abstract
The Japanese beetle Popillia japonica is a pest insect that feeds on hundreds of species of wild and cultivated plants including important fruit, vegetable, and field crops. Native to Japan, the pest has invaded large areas of the USA, Canada, the Azores (Portugal), Italy, and Ticino (Switzerland), and it is considered a priority for control in the European Union. We determined the complete mitochondrial genome sequence in 86 individuals covering the entire distribution of the species. Phylogenetic analysis supports a major division between South Japan and Central/North Japan, with invasive samples coming from the latter. The origin of invasive USA samples is incompatible, in terms of the timing of the event, with a single introduction, with multiple Japanese lineages having been introduced and one accounting for most of the population expansion locally. The origin of the two invasive European populations is compatible with two different invasions followed by minimal differentiation locally. Population analyses provide the possibility to estimate the rate of sequence change from the data and to date major invasion events. Demographic analysis identifies a population expansion followed by a period of contraction prior to the invasion. The present study adds a time and demographic dimension to available reconstructions.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| 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".