Diet breadth and anti-predator strategies in desert locusts and other Orthopterans
Bibliographic record
Abstract
A density-dependent change from a cryptic to an aposematic antipredator strategy has recently been suggested as a possible functional explanation for phase change in the desert locust (Schistocerca gregaria Forskål). Predators learn to avoid locusts that have fed on toxic plants faster when they are in the brightly colored gregarious phase than when they are green and solitarious. We review recent work comparing acquisition of a defensive compound via food selection between solitarious, transiens (solitarious locusts in transition to the gregarious phase) and gregarious locusts. Lab experiments showed that solitarious locusts were deterred at first contact with hyoscyamine, a plant compound that protects against predators, but later habituated to the compound and incorporated it into the diet (albeit at a low rate). By contrast, gregarious and transiens locusts fed readily on the compound. A computer simulation showed how low-density, solitarious locusts would not benefit much from consuming the compound, because they escape predation by avoiding detection. However, for high-density transiens and gregarious locusts, for whom crypsis is no longer an option, acquiring toxicity dramatically decreases predation risk. A survey of the literature showed that solitarious locusts exhibit a narrower diet breadth than gregarious locusts, suggesting that solitarious locusts avoid defensive plant compounds, whereas gregarious locusts use a mix of compounds in the gut as a defence against predators. Gut-mediated antipredator defences might be more widespread among Orthopterans, especially brightly colored species, than has previously been realized. In particular, it remains to be investigated whether density-dependent aposematism and changes in food selection toward chemical defense, play a role in phase change in other locust species.
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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 | 0.001 | 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".