Identification and Seasonal Abundance of Web- and Air-Borne Sex Pheromone Components of Western Black Widow Spiders, Latrodectus hesperus
Bibliographic record
Abstract
Sex pheromones mediate mate location in many animal taxa. Widow spider males are attracted to sex pheromones disseminating from female webs. Upon arrival on a web, males court in response to web-borne contact pheromone components. N-3-Methylbutanoyl-O-methylpropanoyl-L-serine methyl ester (1) is the single known, weakly effective, contact pheromone component of female western black widows, Latrodectus hesperus. Moreover, the seasonal periodicity of pheromone signalling by female spiders is unknown. We tested the hypotheses that females of L. hesperus (1) deposit multiple contact pheromone components on their web that transition to mate-attractant pheromone components, and (2) increase pheromone signalling during the primary mating season. Analyses of web extract by gas and liquid chromatography-mass spectrometry (GC-MS; LC-MS) revealed N-3-methylbutanoyl-O-methylpropanoyl-L-serine (7), the corresponding acid of 1. Web extract of unmated female L. hesperus, and the synthetic blend of 1 and 7, were equally effective in eliciting courtship by males but web extract induced more sustained courtship. Tested singly, 7 prompted longer courtship behaviour by males than 1. Synthetic isobutyric acid (10), the hydrolysis product of 1 and 7, attracted male spiders in a field experiment. The abundance of 1 and 7 on female webs, with expected corresponding dissemination of 10 from webs, peaked during the summer when males are most abundant, indicating strategic sexual signalling by female spiders.
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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 | 0.000 | 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".