Fluorescent and ultraviolet sexual dichromatism in the blue‐winged parrotlet
Bibliographic record
Abstract
Abstract The presence of sexual differences in plumage coloration (sexual dichromatism) is frequent in birds. However, in many cases, humans cannot detect colour differences that are discernible to birds and it is therefore necessary to employ objective methods that contemplate the characteristics of the avian visual system for the study of plumage coloration. An understudied property of feather coloration is the occurrence of fluorescence, which has been described almost exclusively in parrots from the Eastern Hemisphere using non‐objective methods and has been attributed to yellow pigments that are only present in psittacids. In this study, we explore fluorescence and sexual dichromatism through objective and quantitative methods in the plumage of a Neotropical species, the blue‐winged parrotlet F orpus xanthopterygius . We measured plumage reflectance and fluorescence emission on museum skins using spectrophotometry and spectrofluorometry, respectively. The reflectance analysis revealed the presence of ultraviolet sexual dichromatism that adds to the differences in the visible range of wavelengths that are detectable by humans. The spectrofluorometric analysis showed that fluorescence is indeed present in this species, both in green plumage patches, where fluorescent pigments are presumably located, and in the blue rump of males, where colour is considered to be purely structurally based. The sexes differed in the intensity and wavelength of their fluorescence emission, representing the first finding of fluorescence sexual dichromatism in birds.
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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 | 0.000 |
| 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) | 0.000 | 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".