Competition and cuckoldry: estimating fitness of alternative reproductive tactics in plainfin midshipman
Bibliographic record
Abstract
There has been much debate about how male alternative reproductive tactics (ARTs) evolve. In particular, researchers question whether ARTs have evolved as a conditional, ‘best of a bad job’ strategy where one tactic has higher fitness than the other, or whether they have evolved as a result of a genetic polymorphism where both tactics have equal fitness. Despite the large number of species known to have ARTs, tests of equal fitness between tactics have only been conducted in a handful of species. We tested the prediction of equal fitness using the plainfin midshipman (Porichthys notatus), a species with two well characterized male ARTs: guarding type I males and cuckolding type II males. We collected data across three years and three sampling locations to determine the proportion of each reproductive tactic, as well as the proportion of offspring sired by each male type using microsatellite markers. Our analysis suggests that males adopting the conventional guarding tactic likely have higher fitness compared to males adopting the cuckolder type II tactic. Also, we show that the guarding male tactic is able to gain paternity through cuckoldry, and that these males, who sometimes guard and sometimes cuckold, are responsible for the majority of paternity lost within nests. Indeed, the classic cuckolding type II males were responsible for only a small fraction of the paternity lost. These results highlight the degree of flexibility in male behaviour even among individuals adopting the same male tactic. Taken together, our results provide the first exploration of the evolution of male ARTs in plainfin midshipman and, given the tractability of midshipman system, a valuable next step will be to look for gene-by-environment interactions on tactic development and expression.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 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) | 0.001 | 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".