Identification and field testing of ester sex pheromone components of the click beetles <i>Dalopius maritimus</i> and <i>Dalopius asellus</i>
Bibliographic record
Abstract
The Nearctic click beetles Dalopius maritimus and Dalopius asellus are common on agricultural land in western North America but their sex pheromones were not known. Here we report the identification of the major sex pheromone components of these species. Gas chromatographic-mass spectrometric (GC-MS) analyses of sex pheromone gland extract of female D. maritimus revealed seven compounds of which ( Z,E)- and ( E,E)-farnesyl octanoate were deemed candidate pheromone components based on their terpenoid structure, which is common among click beetle pheromones. In field experiments, traps baited with synthetic ( Z,E)-farnesyl octanoate captured many male D. maritimus, whereas ( E,E)-farnesyl octanoate was neither attractive on its own nor did it enhance the attractiveness of ( Z,E)-farnesyl octanoate, indicating that ( Z,E)-farnesyl octanoate is the major pheromone component of D. maritimus. Gas chromatographic-electroantennographic detection (GC-EAD) analyses of pheromone gland extract of female D. asellus revealed a single compound that elicited responses from male antennae. GC-MS analysis determined that this compound was neryl octanoate, and that the second-most abundant compound in gland extracts was ( E,E)-farnesyl octanoate. In field experiments, traps baited with synthetic neryl octanoate captured many male D. asellus, whereas ( E,E)-farnesyl octanoate—which was tested singly and in binary combination with neryl octanoate—had no pheromonal function. These data indicate that neryl octanoate is the major pheromone component of D. asellus. Our findings add to the knowledge of sexual communication systems in click beetles. Synthetic pheromone lures can now be developed to monitor the abundance of these species on agricultural land.
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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".