Morphology of the Alimentary Canal of <I>Chrysoperla rufilabris</I> (Neuroptera: Chrysopidae) Adults in Relation to Microbial Symbionts
Bibliographic record
Abstract
A study of the internal morphology of the alimentary canal of Chrysoperla rufilabris (Brumeister) adults in relation to yeast symbionts was conducted using light, scanning, and transmission electron and epifluorescence microscopy. The alimentary canal of field-collected adults possessed a single large (≈300–400 μm in length) diverticulum at the posterior end of the foregut. Although yeast cells (4.0–6.5 μm) were distributed throughout the alimentary canal, large numbers of blastically dividing cells (i.e., yeast) were observed within the diverticulum. The diverticulum interior was highly convoluted and folded transversely and longitudinally, and yeast cells were observed to accumulate within the folds. Large tracheal trunks were attached to the lateral side of the diverticulum, suggesting a high demand for gas exchange within this organ. The diverticulum was lined with cuticle, and the underlying tissues did not contain large amounts of endoplasmic reticulum, mitochondria, or Golgi complex, indicating that minimal absorption occurred within this gut region. This suggested that the high potential for gas exchange in the diverticulum by the tracheal trunks was primarily to support yeast metabolic activity. All size classes (i.e., 0.1, 4.0, and 10.0 μm) of fluorescence particles ingested by newly eclosed adults eventually ended up in the midgut and hindgut regions, indicating that the foregut and/or diverticulum do not possess an absolute mechanism for retaining particles based on size. However, all size classes of the fluorescent particles typically persisted within the diverticulum. The evident confluence between the diverticulum lumen and the gut lumen suggested a free exchange or flow of fluids between these regions. The proventriculus (proximal to the diverticulum) was pronounced and consisted of a series of long “hairs,” short “hairs,” and small spine-like structures projecting into the midgut. Large numbers of yeast cells were observed in association with the proventricular hairs, and these hairs may play a role in the retention of yeast cells. The midgut possessed typical absorptive structures (i.e., microvilli), and large numbers of mitochondria, rough endoplasmic reticulum, and Golgi complex were observed in midgut epithelial cells. Because evidence indicated no or minimal absorption of nutrients within the diverticulum, it was concluded that nutritional factors provided by the yeast must be transferred to the midgut where absorption occurs. Large numbers of yeast cells enclosed within a well-developed peritrophic matrix were observed in the midgut, suggesting that the yeast themselves may serve as a source of nutrients. Whereas the exact mechanism by which yeast contribute to the nutrition of C. rufilabris adults was not determined, morphological evidence obtained in this study supported the hypothesis that chrysopids form a mutualistic symbiosis with yeast and that the esophageal diverticulum was a specialized structure for housing them.
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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".