Sperm swimming speed and morphology differ slightly among the three genetic morphs of ruff sandpiper (Calidris pugnax), but show no clear polymorphism
Bibliographic record
Abstract
The ruff sandpiper ( Calidris pugnax ) is a lekking shorebird with three male morphs that differ remarkably in behavior, ornaments, size, and endocrinology. The morphs are determined by an autosomal inversion. Aggressive Independents evolved first, female-mimicking Faeders ~4 mil year ago when a short segment of a chromosome reversed in orientation, and semi-cooperative Satellites ~70,000 years ago through a recombination of the Independent and Faeder inversion-segment genotypes. Although the genetic differences between the morphs affect numerous phenotypic traits, it is unknown whether they also affect sperm traits. Here, we use a captive-bred population of ruffs to compare ruff sperm to that of other birds and compare sperm swimming speed and morphology among the morphs. Ruff sperm resembled those of passerines, but moved differently. Faeder sperm moved the slowest and had the longest midpiece. Independents’ sperm were neither the fastest nor the least variable, but had the shortest tail and midpiece. Although the midpiece contains the energy-producing mitochondria, its length was not associated with sperm swimming speed. Instead, two of three velocity metrics weakly positively correlated with head length (absolute and relative). We conclude that there is an indication of quantitative differences in sperm between morphs, but no clear sperm polymorphism.
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 | 0.001 | 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".