Allometric relationships and character evolution in<i>Onthophagus taurus</i>(Coleoptera: Scarabaeidae)
Bibliographic record
Abstract
Allometric relationships in primary sexual traits (male and female genitalia), secondary sexual traits (male horns and female carinae), and non-sex-related traits (external body traits, epipharynx traits) were studied in the dung beetle Onthophagus taurus. Model II regressions of log-transformed data were used to quantify relationships, with pronotum width as regressor and indicator of overall body size. Slopes (allometric values) for the different trait categories were significantly different, with secondary sexual traits showing the highest values (higher than 1.0), followed by external body traits (slightly lower than 1.00) and epipharynx traits (around 0.2). Primary sexual traits and body size were mostly uncorrelated and genital sizes were virtually constant. Allometries of secondary sexual traits were quite different in the two sexes: the relationship between male horn length and pronotum width was approximately sigmoidal, while that between female carina length and pronotum width was linear. External body traits had significantly higher allometric values in females than in males. Our results suggest that traits in the different categories are under different kinds of selection. Genital allometries can be explained on the basis of sexual selection by cryptic female choice or by the lock-and-key hypothesis. Among secondary sexual characters, male horn morphology seems to be mostly "environmentally" determined and sexual selection would affect only a component of the developmental mechanism of horn expression. External body characters are likely under natural selection, even though a few traits could be sex-related. Finally, in both sexes, internal epipharynx traits seem to be subject to the same selective pressure, probably because males and females use the same feeding niche. The constancy of genital sizes in O. taurus suggests that in developmental processes, more is invested in primary sexual traits (to produce genitalia of the proper size) than in secondary sexual or body traits. Males receiving low quantities of food may incur costs associated with a small horn or small body size, but do not incur costs associated with small genitalia. Females probably share the same developmental pattern.
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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 | 0.001 | 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".