Avoiding the cost of males in obligately asexual <i>Daphnia pulex</i> (Leydig)
Bibliographic record
Abstract
Asexual organisms are thought to gain an advantage by avoiding the cost of producing males. In the cladoceran Daphnia pulex (Leydig), male production is determined by the environment and is independent of the origin of the asexual obligate parthenogens from the sexual cyclical parthenogens. If there is a cost to producing males, successful obligate parthenogens should have reduced or eliminated male production. Field and laboratory observations showed that obligate parthenogens have much-reduced male production compared to cyclical parthenogens. Although the reduction or elimination of males in the obligate parthenogens suggests that the cost of males is avoided, the coexistence of sexual and asexual forms of D. pulex may be partially explained by cyclical parthenogens compensating for the cost of males by having greater fecundity. In addition, the absence of a mating constraint for the obligate parthenogens may favour an increased allocation to asexual diapausing eggs earlier in the season compared to the cyclical parthenogens which require mating with males to produce sexual diapausing eggs. No difference in the production of diapausing eggs was observed, probably because males were abundant in populations of cyclical parthenogens and do not appear to limit the production of sexual diapausing eggs. D. pulex is a useful system for determining the ecological consequences of abandoning sexual reproduction and explaining the coexistence of sexual and asexual forms of a species.
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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 | 0.001 |
| 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".