Data from: Threshold elemental ratios and the temperature dependence of herbivory in fishes
Bibliographic record
Abstract
1. Herbivorous ectothermic vertebrates are more diverse and abundant at lower latitudes. While thermal constraints may drive this pattern, its underlying cause remains unclear. We hypothesized that this constraint stems from an inability to meet the elevated phosphorus demands of bony vertebrates feeding on P-poor plant material at cooler temperatures because low gross growth efficiency at warmer temperatures facilitates higher P ingestion rates. We predicted that dietary carbon:phosphorus (C:P) should exceed the threshold elemental ratio between carbon and P-limited growth (TERC:P) for herbivores feeding at cooler temperatures, thereby limiting the range of herbivorous ectothermic vertebrates facing P-limited growth. 2. We tested this hypothesis using the Andean suckermouth catfishes Astroblepus and Chaetostoma. Astroblepus are invertivores that inhabit relatively cool, high-elevation, streams while Chaetostoma are grazers that inhabit relatively warm, low-elevation streams. We calculated TERC:P for each genus across its elevational range and compared these values to measured values of food quality over an elevational gradient in the Andes. We also broadly summarized measurements of TERC:P across diverse groups of fishes. 3. Supporting our hypothesis, we found that dietary C:P was predicted to exceed the TERC:P for the grazer Chaetostoma near the highest elevation where this genus has been recorded. Conversely, the TERC:P for the invertivore Astroblepus was consistently higher than that of Chaetostoma and thus its dietary C:P never approached the TERC:P. We found that, among all fishes, omnivores had higher average TERC:P than invertivores, and TERC:P did not vary with temperature. 4. Our results suggest that, at least for Andean suckermouth catfishes, cool temperatures constrain herbivory at higher elevations. Increased gross growth efficiency at cooler temperatures evidently restricts the ability of P-limited consumers to meet P demand. However, our survey of fish TERC:P estimates suggests that some fishes are able to circumvent this constraint through behavioral and life history adaptations that reduce P demand or increase P use efficiency. 5. The physiological tradeoffs underlying these functional shifts reveal that geographic dietary patterns can be predicted by stoichiometric theory, but variation in food quality and consumer traits that reduce P demand and/or increase P efficiency can create exceptions to these patterns.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| 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) | 0.004 | 0.001 |
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".