The importance of sunbirds as pollinators of the southern African plants Alberta magna and Streptocarpus dunnii.
Bibliographic record
Abstract
Bird pollination is important for plant reproduction and is found in about 65 flowering plant families. I studied putative bird pollination systems of two southern African plant species, Alberta magna (Rubiaceae), which grows above cliffs and Streptocarpus dunnii (Gesneriaceae), which occurs among boulders in open grassland. A special emphasis of this study was to test the utility of close-focusing motion-activated camera traps for documenting bird pollination of plant species that are rare and occur in habitats that present challenges for conventional bird pollination studies. The aims of this project were to 1) quantify floral traits for comparison with other bird-pollinated species; 2) establish the breeding systems, including reliance on pollinators for reproduction; 3) identify floral visitors and measure their contribution to reproductive success; and 4) determine if seed production is pollen limited. Floral traits of S. dunnii, including large volumes of dilute nectar and long tube lengths, also aligned with an ornithophilous pollination syndrome. In naturally-pollinated plants, overall fecundity was high, with 80% of flowers developing fruits with large numbers of seeds. Malachite sunbirds (Nectarinia famosa) were the only legitimate visitor to flowers of S. dunnii. Greater double-collared sunbirds (Cinnyris afer), which have shorter bills than malachite sunbirds, occasionally rob flowers of nectar. Streptocarpus dunnii was found to be fully self-compatible but does not self-autonomously. Selective exclusion experiments showed that the species is almost entirely reliant on birds for seed production. The species did not experience pollen limitation, indicating that sunbirds are effective pollinators. Measured floral traits of A. magna, including large volumes of dilute nectar and long tube lengths, were consistent with an ornithophilous pollination syndrome. Motion triggered cameras and observations showed that southern double-collared sunbirds (Cinnyris chalybeus) and olive sunbirds (Cyanomitra olivacea) were the most common visitors to A. magna, while amethyst sunbirds (Chalcomitra amethystina) were occasional visitors. Selective exclusion experiments showed that bird visitors are important for reproductive success which was found not to be pollen-limited. The low levels of fecundity in A. magna indicate that there may be other potential factors that limit seed production in this species and the degree of self-compatibility in this species was not firmly established. I conclude that both species are specialized for pollination by sunbirds and that close-focusing camera traps are effective for documenting bird pollination systems of rare plant species which occur in habitats that are challenging for conventional human observations.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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".