Male colour variation in a eurytopic African cichlid: the role of diet and hypoxia
Bibliographic record
Abstract
Species that cross strong environmental gradients are expected to face divergent selective pressures that can act on sexually-selected traits. In the present study, we examine the role of hypoxia and carotenoid availability in driving divergence in two sexually-selected traits, male colour and reproductive behaviour, in the African cichlid Pseudocrenilabrus multicolor victoriae. Low-dissolved oxygen (DO) (hypoxic) environments are expected to be energetically challenging; given that male nuptial colour expression and courtship displays can be costly, we expected fish in low-DO versus high-DO environments to differ in these traits. First, a field survey was used to describe natural variation in male nuptial colour patterns and diet across habitats divergent in DO. Next, using wild-caught fish from a low-DO and high-DO habitat, we tested for differences in reproductive behaviour. Finally, a laboratory rearing experiment was used to quantify the interaction of DO and diet (low- versus high-carotenoid availability) on the expression of male colour during development. In energetically challenging low-DO environments, fish were more red and, in high-DO environments, fish were typically brighter and more yellow. The frequency of reproductive displays in fish of low-DO origin was 75% lower, although this had no consequence for brooding frequency (i.e. both populations produced the same number of broods on average). Our laboratory rearing study showed carotenoid availability to be important in colour production with no direct influence of DO on colour. Additionally, weak patterns of diet variation across wild populations suggest that other factors in combination with diet are contributing to colour divergence.
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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 | 0.000 |
| 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) | 0.001 | 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".