Sun-Compass Orientation During Natal Dispersal in Hatchling Blanding's Turtles (Emydoidea blandingii)
Bibliographic record
Abstract
Blanding's turtle hatchlings emerge from their natal nests naïve to environmental stimuli and primarily sense visual cues on the horizon as a dispersal target. During a period of hours or days, hatchlings develop a compass mechanism that allows them to maintain a direction of travel, even when the target is not visible. We examined the dispersal directions of Blanding's turtle hatchlings captured during dispersal by translocating them into a circular arena in a field of corn in order to measure their dispersal direction guided by a compass mechanism. To test for use of a sun compass, a magnetic compass, or both, we observed dispersal direction of hatchlings released at the center of the arena. Hatchlings were released in an initial trial, treated with normal (no-shift) or 6-hr clock-shifted photoperiods for 4 to 10 days, and released into the arena for a second trial with magnets (or non-magnetic controls) adhered to their carapaces. We predicted that clock-shifting would reduce dispersal angle 90° and disruption of magneto-reception would disorient hatchlings. All four treatment groups dispersed directionally during first trials (Rayleigh's Z-tests; all p < 0.001) and in second trials dispersal angles were unchanged in hatchlings with magnets (Watson's U2; both p > 0.50); they were not using a geo-magnetic compass. Hatchlings that were not clock-shifted maintained their initial heading but clock-shifted hatchlings reduced dispersal angle a mean of 111°, not significantly different than the experimental prediction of 90° (Rayleigh's Z = 22.217, p < 0.001, no-shift; Rayleigh's Z = 19.286, p < 0.001, shift; Watson's U255,58 p < 0.001). An analysis of dispersal angles using only daily means of groups of turtles each released on different days also showed significant directionality, no magnet effect, and a significant clock-shift effect (two-sample Hotelling test, p < 0.002). Hatchlings were using a sun compass exclusively.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 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".