Low proportions of reproducing hemiclonal females increase the stability of a sexual parasite–host system (<i>Rana esculenta</i>, <i>R. lessonae</i>)
Bibliographic record
Abstract
1 The number of reproductive events per lifetime affects all levels of ecological complexity, including the structure and dynamics of species communities. Here we investigate a sexual parasite–host system with two water frog species of which one (Rana esculenta, E) is a hemiclonal hybrid that depends on one of its parental species (R. lessonae, L) for successful reproduction. Previous theoretical models have shown that relative fecundities are important for the species composition and stability of this system, but empirical data from natural mixed LE-populations were lacking. 2 We used three different methods to estimate the proportion of annually reproducing hybrid and parental females: (a) screening for eggs through a tiny incision into the belly skin, (b) measuring plasma hormone titres from blood samples and (c) counts of egg clumps deposited into the pond. 3 After accounting for the respective adult population sizes of the two female types – calculated from mark–recapture analyses – we found that all three estimates revealed a higher proportion of reproducing L- than E-females. Ratios ranged from 1·43 (method c), to 1·90 (a) to 2·38 (b), with an average of 1·90. 4 We also investigated three potential causes for the fecundity difference (age structure, hybrid sterility and differences in reproductive costs) but could not find compelling evidence for any of them. We hypothesize that size-related differences in energy budgets offer the most probable explanation. 5 The consequences of the observed species differences in annual reproductive success were analysed with a theoretical model. The higher proportion of reproducing R. lessonae females increases the possibilities for stable coexistence in mixed LE-populations under a variety of combinations of mating patterns, relative fecundity and larval performance. The results, however, also indicate new limits for coexistence and highlight the paramount importance of larval competition for explaining the composition and dynamics of mixed LE-populations.
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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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".