Ocellar Pigmentation and Phototaxis in the Nematode <i>Mermis Nigrescens</i>: Changes During Development
Bibliographic record
Abstract
After 1 or 2 years of dormancy in the soil, Mermis nigrescens females emerge to lay eggs on vegetation where their grasshopper hosts are likely to feed. Females collected at this life stage exhibit a strong positive phototaxis and have a tubular region of pigmentation near the anterior tip consisting of concentrated oxyhaemoglobin. A previous investigation of the scanning motion of the 'head' and orientation of the 'neck' has implicated the shadowing of a photoreceptor inside the tube as the mechanism for identifying the direction of light during phototaxis. Here, we describe the development of the pigment in young adult females and investigate phototaxis in early developmental stages that lack the pigment. The orientation of the neck to a horizontal 420 nm stimulus (intensity 10(13 )photons s(-)(1 )cm(-)(2)) was measured for unpigmented fourth-stage larvae and immature adult females as well as mature females with pigmented ocelli. The orientation of the larvae and immature adults was weakly negative, whereas that of the mature adults was strongly positive. Head and neck movements were otherwise the same in the three stages. Thus, the pigmentation appears to be required for positive phototaxis, and the results provide further support for the shadowing role of ocellar haemoglobin.
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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 | 0.000 | 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".