The relationship between nectar spur curvature in jewelweed (<i>Impatiens capensis</i>) and pollen removal by hummingbird pollinators
Bibliographic record
Abstract
Floral nectar spurs are hypothesized to have had a major role in the evolution of floral diversity and plant-pollinator coadaptation. We examined variation in the degree of nectar spur curvature in two species of jewelweed (Impatiens capensis and Impatiens pallida) pollinated by different sets of pollinators. To distinguish between adaptive and nonadaptive explanations for between-species differences in curvature, we determined the relationship between spur curvature and pollen removal, which is one estimate of male reproductive success. Spur curvature exhibited considerable variation both within and among three populations, with spur angles ranging from 0° to 297°. A greenhouse experiment determined that spur curvature of I. capensis flowers has a broad-sense heritability of 0.636. Laboratory experiments indicated that flowers having recurved spurs deposit significantly more pollen grains on hummingbird visitors than flowers having perpendicular spurs, apparently as a result of greater contact between the androecium of curve-spurred flowers and the upper bill of hummingbirds. We also found a significant relationship between spur curvature and flower length, suggesting a developmental link between the two traits. We discuss the degree of spur curvature in bird-pollinated I. capensis as a function of both adaptive evolution and developmental constraint.Key words: pollination, nectar spurs, hummingbirds, Impatiens capensis, Impatiens pallida, pollen export, floral morphology, floral polymorphisms.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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 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".