Isotopes (δ2H) in wings and stored lipids of fall migratory monarch butterflies (Danaus plexippus) provide insights into population structure and nectaring origins
Bibliographic record
Abstract
We measured stable H isotope ( δ 2 H) concentrations in wing and stored body lipids of fall migrating monarch butterflies ( Danaus plexippus ) from the eastern North American subpopulation along a transect from southern Ontario to overwintering sites in central Mexico from 2019 to 2021. We analysed wing δ 2 H to infer natal origins using both a spatially explicit approach and a categorical approach which assigned origins to north, central and southern portions of the breeding range west of the Appalachians. The fall migration differed in composition annually likely reflecting differential production of monarchs latitudinally due to varying climate conditions. Surprisingly, the composition of overwintering monarchs indicated that northern breeding regions contributed between 30 and 55% of overwintering monarchs across years, estimates far higher than previously reported. We suggest that northern productions zones are becoming more important compared to earlier decades. Bulk lipid δ 2 H values showed patterns of general increase from Ontario through Oklahoma before declining again through to the overwintering sites, supporting that monarchs acquire nectar for lipid production en route and finally at the overwinter sites at high-altitude regions of central Mexico. We recommend that stable isotope monitoring, especially of overwintering monarchs, be conducted annually to track production zones contributing to annual recruitment.
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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) | 0.001 | 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".