Quantifying the acid-base status of dragonflies across their transition from breathing water to breathing air
Bibliographic record
Abstract
Amphibiotic dragonflies show a significant increase in hemolymph total CO2 (TCO2) as they transition from water-breathing to air-breathing. This study examines the hemolymph acid-base status of dragonflies from two families (Aeshnidae and Libellulidae) as they transition from water to air. CO2 solubility (αCO2) and the apparent carbonic acid dissociation constant (pKapp) were determined in vitro, and pH/bicarbonate [HCO3−] plots were produced by equilibrating hemolymph samples with PCO2 between 0.5-5 kPa in custom-built rotating microtonometers. Hemolymph αCO2 varied little between families and across development (mean 0.355±0.005 mmol l−1 kPa−1) while the pKapp was between 6.23 to 6.27, similar to values determined for grasshopper hemolymph. However, the non-HCO3− buffer capacity for dragonfly hemolymph was uniformly low relative to other insects (3.6 to 5.4 mmol l−1 pH−1). While aeshnid dragonflies maintained this level as bimodally-breathing late-final instars and air-breathing adults, the buffer capacity of bimodally-breathing late-final instar Libellula nymphs increased substantially to 9.9 mmol l−1 pH−1. Using the pH/[HCO3−] plots and in vivo measurements of TCO2 and PCO2 from early-final instar nymphs, it was calculated that the in vivo hemolymph pH was 7.8 for an aeshnid nymph and 7.9 for a libellulid nymph, respectively. The pH/[HCO3−] plots show that the changes in acid-base status experienced by dragonflies across their development are more moderate than those seen in vertebrate amphibians. Whether these differences are due to dragonflies being secondarily aquatic, or arise from intrinsic differences between insect and vertebrate gas exchange and acid-base regulatory mechanisms, remains an open question.
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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) | 0.000 | 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 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".