Glandular quinoline-derivates protect crustacean woodlice from spider predation
Bibliographic record
Abstract
In evolutionary time, aquatic crustaceans colonized land and faced new terrestrial predators such as spiders and ants. We tested the hypothesis that the crustacean terrestrial woodlouse Porcellio scaber produces defensive metabolites that provide protection against terrestrial predators. When attacked by a predator, P. scaber expels proteinaceous secretions from its tegumental glands. Analyses of gland secretion extracts by gas chromatography–mass spectrometry and by liquid chromatography–mass spectrometry revealed four metabolites: methyl 8-hydroxy-quinoline-2-carboxylate, methyl 8-hydroxy-4-methoxy-quinoline-2-carboxylate, methyl 8-(sulfooxy)quinoline-2-carboxylate and methyl 4-methoxy-8-(sulfooxy)quinoline-2-carboxylate, the latter three being natural products not previously known. In behavioural experiments, Steatoda grossa spiders readily preyed on Tenebrio molitor beetles but avoided chemically well-defended P. scaber . When beetles were rendered chemically well-defended by topical applications of either P. scaber gland secretion extract or synthetic metabolites identified in these extracts, spiders rejected the beetles as prey. Our data support the hypothesis that P. scaber produces defensive metabolites against terrestrial predators. We show that the crustacean P. scaber , like many insects, is chemically defended against predators.
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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) | 0.002 | 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".