Glandular quinoline-derivates protect crustacean woodlice from spider predation
Bibliographic record
Abstract
Abstract In evolutionary time, aquatic crustaceans colonized land and faced new terrestrial predators such as spiders and ants. Working with the crustacean woodlouse Porcellio scaber , we tested the hypothesis that the shift from aquatic to terrestrial habitat prompted the evolution of defensive metabolites against terrestrial predators. When attacked by a predator, P. scaber woodlice expel proteinaceous secretions from their tegumental glands. Analyses of gland secretion extracts by gas chromatography-mass spectrometry and by liquid-chromatography-tandem 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 preyed on chemically undefended Tenebrio molitor beetles but avoided chemically defended P. scaber . When beetles were rendered chemically 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 the evolutionary transition of crustaceans from aquatic to terrestrial habitats prompted the evolution of defensive metabolites against terrestrial predators. We show that crustaceans, like many insects, are chemically defended against predators. Abstract Figure Graphical abstract Under attack by the predatory spider Steatoda grossa , the crustacean Porcellio scaber releases four defensive 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 previously unknown natural products.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".