The role of multiple reproductive barriers: strong post-pollination interactions govern cytotype isolation in a tetraploid–octoploid contact zone
Bibliographic record
Abstract
BACKGROUND AND AIMS: Polyploidy is an important contributor to sympatric speciation and assortative mating is a key mechanism driving cytotype interactions in contact zones. While strong reproductive barriers can mediate the coexistence of different cytotypes in sympatry, positive frequency-dependent mating disadvantage ultimately drives the transition to single-ploidy populations. However, comprehensive estimates of reproductive isolation among cytotypes and across multiple barriers are rare. We quantify the strength of isolation across multiple reproductive stages in a tetraploid-octoploid contact zone to understand the potential for coexistence. METHODS: Assortative mating due to flowering asynchrony, pollinator behaviour, morphological overlap, self-fertilization and gametic competition between tetraploid and octoploid Gladiolus communis in a contact zone in the Western Iberian Peninsula were assessed in natural and experimental populations to quantify reproductive isolation (RI) between cytotypes. KEY RESULTS: Tetraploids and octoploids have a high degree of overlap in flowering time and similar floral morphology, and are visited by generalist insects without cytotype foraging preferences, resulting in weak pre-pollination RI (from 0.00 to 0.21). In contrast, post-pollination isolation resulting from gametic selection was a strong barrier to inter-cytotype mating, with ploidy composition in stigmatic pollen loads determining the levels of RI (from 0.54 to 1.00). Between-cytotype cross-incompatibility was relatively high (RI from 0.54 to 0.63) as was isolation acquired through self-pollination (RI of 0.59 in tetraploids and 0.39 in octoploids). CONCLUSIONS: Total RI was high for both tetraploids (from 0.90 to 1.00) and octoploids (from 0.78 to 0.98). Such high rates of assortative mating will enable cytotype coexistence in mixed-ploidy populations by weakening the impacts of minority cytotype exclusion. This study reveals the key role of gametic selection in cytotype siring success and highlights the importance of comprehensive estimates across multiple reproductive barriers to understand cytotype interactions at contact zones.
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 | 0.000 |
| 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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".