Habitat-dependent reduction of sexual dimorphism in geometric body shape of Haida Gwaii threespine stickleback
Bibliographic record
Abstract
We investigated the extent of sexual dimorphism in body shape in adult threespine stickleback (Gasterosteus aculeatus) from 39 lakes, eight streams, and five marine (two brackish, three full marine) localities on the Haida Gwaii archipelago off the mid-coast of British Columbia, as well as three lakes from southern British Columbia with benthic–limnetic species pairs. Based on digital images of 709 males and 593 females, body shape was quantified using discriminant function analysis on partial warp scores generated from twelve homologous landmarks. All populations showed males with higher positive values for canonical vector 1, which are characterized by larger heads, larger gape, posteriad dorsal spines, posteriad pelvis, longer anal fin, and deep posterior caudal depth relative to those in females. Geographical variability was present, with the highest dimorphism occurring in two of the marine habitats in addition to large lakes, whereas reduced dimorphism occurs in small shallow dystrophic ponds. We suggest that this reduction is the derived condition and is primarily due to loss of niche breadth and convergence in body shape between the sexes in pond habitats. Analyses of two experimental pond populations indicate that up to 15% of the shape dimorphism can be attributed to habitat-induced phenotypic plasticity.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".