Curious Chiral Cases of Caddisfly Larvae: Handed Behavior, Asymmetric Forms, Evolutionary History
Bibliographic record
Abstract
Studies of right-left asymmetries have yielded valuable insights into the mechanisms of both development and evolution. Larvae from several groups of caddisflies (Trichoptera) build portable asymmetrical cases within which they live. In nearly all species that build spiral-walled tubular cases, the direction of wall coiling is random (equal numbers of dextral and sinistral cases within species) whereas in all species that build helicospiral, snail-like cases the direction of coiling is exclusively dextral. Asymmetrical tubes result from handed behavior, and ∼20% of larvae removed from a spiral-walled, tubular case build a replacement case of opposite chirality. So handed behavior (and hence direction of tube-wall spiraling) is likely learned rather than determined genetically. Asymmetrical larval cases appear to have evolved at least seven times in the Trichoptera, five times as spiral-walled tubes and twice as snail-like helicospiral cases. Helicospiral cases may reduce vulnerability to predation by mimicking snail shells, whereas spiral arrangements of vegetation fragments in tube walls may be more robust mechanically than other arrangements, but experimental evidence is lacking. Within one family (Phryganeidae), one or perhaps two species exhibit an excess of sinistral-walled cases, suggesting that genes that bias handed behavior in a particular direction evolved after handed behaviors already existed (genetic assimilation).
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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 | 0.001 |
| 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".