Evolution of cycloalexy in neotropical Chrysomeline beetles (Coleoptera: Chrysomelidae)
Bibliographic record
Abstract
The larvae of some insects arrange themselves in a tight, orderly circle at rest; a behaviour that Vasconcellos-Neto and Jolivet (1988b) first called "cycloalexy". The word was defined by Jolivet and collaborators in 1990 as a defensive behaviour adopted by insect larvae that form a tight circle with the best defended extremity at the periphery, either heads or abdomens. The formation is also associated with coordinated movements to repel threats. The term has steadily gained acceptance and expanded to include insect nymphs, adult insects and even vertebrates. We review reports of cycloalexy and find the behaviour is less common than suggested. Convincing examples are found only in sawflies, leaf beetles, caterpillars, one weevil and one midge species. We question reports of cycloalexy in penguins, an amphipod crustacean, nymphs of Hemiptera and larvae of Hymenoptera and Neuroptera. We argue that analogous behaviours in mammals are reactive rather than preventive and, hence, not cycloalexic. A molecular phylogeny was reconstructed to evaluate the relationships of 70 species of Neotropical Chrysomelinae and the evolution of cycloalexy. We sequenced five gene segments: nuclear protein-coding CAD and 28S rDNA, mitochondrial 12S rDNA and protein-coding COI and COII. The phylogeny was inferred using Bayesian and Maximum Likelihood (ML) methods and ancestral larval behaviour was reconstructed with ML and Maximum Parsimony methods. The ancestral behaviour reconstructions show five independent evolutionary origins of larval gregariousness in Neotropical chrysomeline beetles, two with maternal care and circular grouping of larvae and one accompanied by cycloalexy. Further, our phylogeny clarifies relationships within Chrysomelinae, and shows a revision is needed: the genus Stilodes is paraphyletic with Zygogramma, Platyphora is polyphyletic and divided into two clades; one with Doryphora nested within and the other with Proseicela.
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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".