Partner supply mediates elevational gradients in the outcome of ant‐hemipteran mutualistic associations
Bibliographic record
Abstract
Abstract Aim Along elevational or latitudinal gradients, the dynamics of mutualistic interactions may be driven by shifts in partner abundance, themselves driven by changes in environmental factors. We test the hypothesis that partner abundance mediates the frequency of associations and investment incurred by partners while associating. Location Western and Eastern slopes of the Andes of Ecuador. Taxon Ants (Hymenoptera, Formicidae) and treehoppers (Hemiptera, Membracidae). Methods Using a combination of visual surveys and sucrose baits, we scored the abundance of ants, treehoppers, and their associations at 500‐meter intervals along two 4000 m elevational gradients in the equatorial Andes (three locations per elevation interval, two 70 m transects per location). We used the size of the treehopper aggregations and of the ant worker force involved in the associations as proxies for the investment partners incur in the interaction. We analysed our data using GLMM with transects as units of analyses and locations as random effects. Results We show that the number of ant‐treehopper aggregations declined with elevation, in parallel with a decline in the abundance of both partners, but with ants declining at a faster rate. Despite this, the numbers of ants and treehoppers within individual aggregations increased with elevation, but this time with the number of treehoppers in the aggregations increasing at a faster rate. Main conclusion We suggest that this elevational gradient in the size of ant‐treehopper aggregations arises from consumer resource‐dynamics, where the partner in short supply elicits greater investment from the other. Within the range of elevations where the interaction is possible, the observation that a smaller proportion of treehopper species engage in mutualism at higher elevations further suggests decreasing benefits of the associations with elevation. Our study suggests that the geography of abundance and supply, and its consequences on cost and demand of services, may dictate the outcome of mutualistic interactions along gradients, with possible implications for the maintenance of biological diversity.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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) | 0.000 | 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".