The Evolution of Offspring Size across Life-History Stages
Bibliographic record
Abstract
Females vary in the size of offspring that they produce, often in a manner that depends on maternal age or stage. This is puzzling, given that offspring size is predicted to evolve to a single optimal value where the gain in fitness from being larger exactly offsets the fitness lost to the mother by producing fewer offspring. We used a stage-structured life-history model to determine the optimal offspring size for females in different stages. We found that optimal offspring size does not vary with maternal stage when offspring fitness depends only on its size and not on the stage of the mother. This negative result holds even with density dependence, when larger offspring compete better. However, a trade-off between offspring size and maternal survival affects the optimal offspring size. The future reproductive value of the female, coupled with the costs and benefits of offspring investment, drives the evolution of stage-dependent offspring size. If producing larger offspring is riskier for mothers, females produce smaller offspring when their reproductive value in the next time step is large relative to current reproductive prospects. These analyses provide a novel framework for understanding why offspring size varies in age- and stage-structured 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 | 0.000 |
| 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 | 0.001 |
| 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".