THE ECOLOGY OF ASYMMETRY IN STICKLEBACK DEFENSE STRUCTURES
Bibliographic record
Abstract
Slight departures from bilateral symmetry are usually associated with reduced fitness. Here we show that an insular freshwater population of Gasterosteus aculeatus exhibits spatial and temporal segregation according to the incidence and direction of asymmetry in the number of bony lateral plates, which are important predator-defense structures. We analyzed 11,263 fish collected from 19 full lake transects over three years, and found that signed asymmetries for plate number were slightly left-side biased. Asymmetries occurred in 55% of the stickleback with more asymmetrics found during cold weather, and more left-biased individuals found during windy conditions, possibly due to environmentally driven activity levels that differ among asymmetric forms. Absolute plate asymmetries were randomly distributed in the lake, but there was a strong shift in signed plate asymmetry from a mean of zero in littoral zones to left-side bias in limnetic zones, probably due to microhabitat choices among asymmetric forms. Video data of avian piscivores on the lake show laterality in prey handling, providing a potential mechanism for asymmetric prey morphology. Our results imply a complex relationship between slight asymmetries and niche space that is relevant to the broader literature on the evolutionary implications of developmental instability and intrapopulation variability.
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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 | 0.001 |
| 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".