Individual variation and environmental context in avian life-history evolution: An experimental approach using mountain bluebirds (Sialia currucoides).
Bibliographic record
Abstract
Reproductive success of organisms is influenced by life-history traits such as growth and reproductive effort, yet little is known about the proximate factors that influence the allocation of resources to different traits, and how these factors interact. I experimentally investigated the influence of several proximate factors on investment in life-history traits of juvenile and adult mountain bluebirds (Sialia currucoides), an altricial, cavity nesting passerine. Supplemental carotenoids enhanced immune response of nestlings, and allowed nestlings that were parasitized by blow fly larvae (Protocalliphora spp.) to gain body mass more quickly compared to parasitized nestlings that did not receive supplemental carotenoids. When parasites were removed from nests, however, no benefits of carotenoid supplementation were evident. This indicates that, although trade-offs between growth and immunity in nestling birds are functionally driven by limitations in the availability of dietary nutrients, these trade-offs are mediated by ectoparasite exposure. Within broods, supplemental carotenoids enhanced immunity of all but the last-hatched nestling, suggesting that this junior nestling may represent a low-cost resource for parasites. Removal of ectoparasite from nests, however, disproportionately benefited nestlings positioned in the middle of the size hierarchy at hatching, suggesting that parasites balance host defense against nutritional value. In many species, annual reproductive investment may include multiple breeding attempts within a season. In each attempt, females may also select social and/or extra-pair mates. Simultaneous manipulations of timing of hatch of first clutches and food availability throughout first breeding attempts showed that female bluebirds were more likely to double-brood when food availability was high, and that the probability of younger or lower-quality females double-brooding depended on the timing of first breeding attempts. Enhanced food availability in first broods also reduced the probab
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 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 | 0.001 |
| 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 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".