Sex-specific performance, trade-offs and trait repeatability across the lifetime of the world's largest semelparous mammal (<i>Dasyurus hallucatus</i>)
Bibliographic record
Abstract
The activities that define survival and reproductive success in animals depend on their physical performance. However, performance is a complex trait, and organisms must balance competing demands of multiple underlying factors every time they undertake an activity. For example, the morphology that increases bite force (i.e. increased head size) - improving fighting ability - should constrain sprinting performance by adding mass to the body. Consequently, trade-offs between fighting and escape performance might be sex specific where sexual dimorphism is present, or pronounced in animals with extreme breeding strategies. Northern quolls (Dasyurus hallucatus) are a sexually dimorphic marsupial, with sex-specific life history strategies; males die after a single synchronous breeding season, while females can live and breed for 2-3 years. We investigated the effects of sex and life history on whole-animal performance and assessed whether sprint speed and bite force trade off among or within individual male and female quolls. We used a repeated measures dataset spanning 3 years. We identified significant sex differences in morphology and performance, notably after breeding, where male sprint speed decreases but female bite force increases. Both body size and body condition were strong predictors of performance. However, we found no trade-off between sprint speed and bite force, suggesting that ecologically relevant tasks for survival and reproduction - fighting capacity and escape ability - may evolve independently in both male and female northern quolls. Finally, we assessed the repeatability of morphological and performance traits and demonstrated the importance of study design when quantifying variance in animal performance, especially for animals with complex life histories.
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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 | 0.001 | 0.001 |
| 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 | 0.000 | 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".