Manipulating developmental stress reveals sex‐specific effects of egg size on offspring phenotype
Bibliographic record
Abstract
The general lack of experimental evidence for strong, positive effects of egg size on offspring phenotype has led to suggestions that avian egg size is a neutral trait. To better understand the functional significance of intra-specific variation in egg size as a determinant of offspring fitness within a life-history (sex-specific life-history strategies) and an environmental (poor rearing conditions) context, we experimentally increased developmental stress (via maternal feather-clipping) in the sexually size-dimorphic European starling (Sturnus vulgaris) and measured phenotypic traits in offspring across multiple biological scales. As predicted by life-history theory, sons and daughters had different responses when faced with developmental stress and variation in egg size. In response to developmental stress, small egg size in normally faster-growing sons was associated with catch-up growth prior to attaining larger adult size, resulting in a reduction in developmental stability. Daughters apparently avoided this developmental instability by reducing growth rate and eventual adult body mass and size. Interestingly, large egg size provided offspring with greater developmental flexibility under poor growth conditions. Large-egg sons and daughters avoided the reduction in developmental stability, and daughters also showed enhanced escape performance during flight trials. Furthermore, large egg size resulted in elevated immune responses for both sexes under developmental stress. These findings show that there can be significant, but complex, context-specific effects of egg size on offspring phenotype at least up to fledging, but these can only be demonstrated by appreciating variation in the quality of the offspring environment and life histories. Results are therefore consistent with egg size playing a significant role in shaping the phenotypic outcome of offspring in species that show even greater intra-specific variation in egg size than starlings.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".