ASYMMETRY IN STRUCTURAL DEFENSES: INSIGHTS INTO SELECTIVE PREDATION IN THE WILD
Bibliographic record
Abstract
Assessment of geographical patterns in fluctuating asymmetry (small, random differences between sides of bilateral characters) among populations shows promise as a tool to resolve the relative biomechanical importance of traits, in addition to being a possible indicator of habitat quality. We used 115 endemic freshwater populations of threespine stickleback (Gasterosteus aculeatus) from Haida Gwaii (Queen Charlotte Islands), British Columbia, Canada, to explore the degree of concordance between geographical variation of asymmetry in a predator defense structure (bony lateral plates) and geographical variation in several indirect measures of predation regime as well as several abiotic habitat variables. We found a geographical cline in the population frequency of lateral plate asymmetries, with reduced asymmetry in the southern clear-water regions of the archipelago characterized by long reaction distances and greater chance of capture by predators, and elevated asymmetry in the northern stained-water regions with poor visibility and low chances of capture. Lateral plate asymmetry was strongly correlated with expression of several defensive armor traits, including total plate numbers among populations, mean cross-sectional diameter of stickleback with the dorsal and pelvic spines erect, and mean degree of overlap between the plates and spine supports. There were no significant correlations between frequency of asymmetric fish and any of our abiotic habitat variables. Stickleback with structural plate asymmetries had fewer trout-induced scars than symmetric fish in the significant majority of populations, and there was a decrease in structural plate asymmetry with age in stained-water habitats, suggesting that trout predators may be selectively removing asymmetric fish in some lakes. This study provides evidence that geographical variation in developmental stability of threespine stickleback, as seen in the frequencies of asymmetry, reflects differences among populations in the importance of structural defenses to fitness rather than differences in habitat quality, and that asymmetry may be a target of selection by predators in wild populations.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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) | 0.000 | 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 teacher head, 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".