Microsatellite Analyses Provide Evidence of Male-Biased Dispersal in the Radiated Tortoise Astrochelys radiata (Chelonia: Testudinidae)
Bibliographic record
Abstract
Dispersal is a major force in shaping the genetic structure and dynamics of species; thus, its understanding is critical in formulating appropriate conservation strategies. In many species, sexes do not face the same evolutionary pressures, and consequently dispersal is often asymmetrical between males and females. This is well documented in birds and mammals but has seldom been investigated in other taxa, including reptiles and, more specifically, nonmarine chelonians. In these species, nest-site fidelity observations are frequent but still remain to be associated with natal homing. Here, we tested for sex-biased dispersal in the radiated tortoise (Astrochelys radiata) from southern Madagascar. Using data from 13 microsatellite markers, we investigated patterns of relatedness between sexes in 2 populations. All Mantel tests indicated significant isolation by distance at the individual level in females but not in males. Furthermore, spatial autocorrelation analyses and 2 analytical approaches designed to assess general trends in sex-specific dispersal also supported male-biased dispersal. On the other hand, comparisons of overall genetic structure among sampling sites did not provide conclusive support for greater philopatry in females, but these tests may have low statistical power because of methodological and biological constraints. Radiated tortoises appear to be both polyandrous and polygynous, and evolutionary processes that may lead to a sex bias in dispersal are discussed with respect to tortoise breeding biology. Female natal homing is hypothesized as a key trait explaining greater female philopatry in A. radiata. These findings highlight the necessity of additional research on natal homing in tortoises, a behavioral trait with direct implications for conservation.
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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 | 0.000 |
| 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".