Species delimitation and invasion history of the balsam woolly adelgid, <i>Adelges</i> ( <i>Dreyfusia</i> ) <i>piceae</i> (Hemiptera: Aphidoidea: Adelgidae), species complex
Bibliographic record
Abstract
Abstract The Adelges ( Dreyfusia ) piceae (Ratzeburg) species complex is a taxonomically unstable group of six species. Three of the species are cyclically parthenogenetic [ Ad . nordmannianae (Eckstein), Ad . prelli (Grossmann), and Ad . merkeri (Eichhorn)] and three are obligately asexual [ Ad . piceae , Ad . schneideri (Börner), and Ad . nebrodensis (Binazzi & Covassi)]. Some species are high‐impact pests of fir ( Abies ) trees, so stable species names are needed to communicate effectively about management. Therefore, to refine species delimitation, guided by a reconstruction of their biogeographic history, we genotyped adelgids from Europe, North America, and the Caucasus Mountains region with 19 microsatellite loci, sequenced the COI DNA barcoding region, and compared morphology. Discriminant analysis of principal components of microsatellite genotypes revealed four distinct genetic clusters. Two clusters were morphologically consistent with Ad . nordmannianae . One of these clusters consisted of samples from the Caucasus Mountains and northern Turkey, and the other included samples from this region as well as from Europe and North America, where Ad . nordmannianae is invasive. A third cluster was morphologically consistent with Ad . piceae , and included individuals from Europe, where it is native, and North America, where it is invasive. In North America, the majority of Ad . piceae individuals were assigned to two geographically widespread clones, suggesting multiple introductions. The fourth cluster included individuals morphologically consistent with Ad . prelli or Ad . merkeri . However, based on genetic assignments, hybrid simulations, and approximate Bayesian computation, we find it likely that these are contemporary hybrids between Ad . nordmannianae and Ad . piceae that arose independently in Europe and North America, so we propose that Ad . prelli and Ad . merkeri are invalid. Finally, we synonymise Ad . schneideri (syn.n.) with Ad . nordmannianae and designate Ad . nebrodensis as subspecies Ad . piceae nebrodensis (stat.n.) . Our revised taxonomy therefore recognises two species: Ad . nordmannianae and Ad . piceae , which we estimate to have diverged recently, during one of the last two interglacial periods. Finally, we comment on this species complex being in the midst of transition between sexual and asexual reproduction, a pattern that is probably common in Adelgidae.
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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 | 0.002 | 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) | 0.000 | 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".