Species Delimitation Under Allopatry: Genomic Divergences Within and Across Continents in Lepidoptera
Bibliographic record
Abstract
ABSTRACT Delimitation of allopatric populations into species remains subjective and largely arbitrary. Many cold-adapted species from the subarctic and Central and Southern European Mountain systems display frequent allopatry with disjunct distributions of their populations. The same concerns Holarctic species which are many and which almost regularly show various degrees of differentiation between the continents. In this study, we analyze high- throughput target enrichment data for ten groups of arctic-alpine and Holarctic lepidopteran species sampled from four main regions across the Holarctic realm – Fennoscandia, North America, Alps and Altai. We first aimed to assess whether the genetic differences in the nuclear genome reflect observed DNA barcode divergences and second, whether the gap between population and species-level differences can be dissected using genomic data. We compared the phylogenetic trees and uncorrected pairwise genetic distances obtained from target enrichment and the mitochondrial cytochrome oxidase I (COI) barcodes for each of the study species. Additionally, we also performed a suite of population genetic and species delimitation analyses to further shed light on patterns of intraspecific variation using a large number of nuclear markers. We observed that in about one half of the cases, DNA barcodes tended to show phylogenetic relationships similar to the target enrichment markers. We report varying levels of nuclear genetic differentiation among the populations analyzed, starting from low differentiation of geographically separated populations to the deeper separation of some Nearctic population and further arctic-alpine disjunction. Given that no single consistent pattern emerged across different case studies, we demonstrate that the delimitation of allopatric populations into species could be done much more efficiently and in a consistent manner if based on a large set of universal genetic loci, which would help in reaching standards for taxonomic delimitation of allopatric populations.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 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".