Intensive agriculture and insect prey availability influence oxidative status and return rates of an aerial insectivore
Bibliographic record
Abstract
Abstract Birds breeding in agricultural landscapes contend with potential reductions in prey availability that may alter behavior and incur physiological costs. Individuals may need to increase foraging intensity, producing elevated reactive oxygen species involved in oxidative damage. Food scarcity or low food quality may also reduce levels of diet‐derived antioxidants. Here, we tested whether short‐term changes in insect biomass on agricultural sites produce changes in the oxidative status of tree swallows ( Tachycineta bicolor ), with the potential to influence return rates. We sampled 368 adult and 374 nestling swallows at five agricultural cropland and grassland‐dominated sites over three years from 2012 to 2014. Blood plasma was assessed for antioxidant capacity (OXY) and reactive oxygen metabolites (ROMs), a marker for oxidative damage. Overall, males appeared to have higher oxidative damage and therefore oxidative stress (calculated as the ratio between ROMs and OXY) than females. Consistent with our hypothesis, aerial insect biomass was a strong predictor of oxidative status in swallows. Adult plasma antioxidants were higher with greater insect biomass, while nestling plasma antioxidants, oxidative damage, and oxidative stress exhibited negative relationships with insect biomass. Annual return rates of adults were predicted by site type, age, fledging success, and oxidative status. In 2013, adult return rates were higher at grassland sites (41%) than at cropland sites (25%) and birds with lower plasma antioxidants the previous year were more likely to return. In 2014, adults were more likely to return if they had fledged more nestlings the previous season and if they had lower levels of oxidative damage the previous year. We conclude that even subtle changes in insect prey availability in agricultural landscapes caused by pesticides, intense cropping, and natural habitat loss can play a key role in swallow oxidative status, with subsequent effects on local return rates.
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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 | 0.001 |
| 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 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".