Assessing species-specific reproductive variation to inform assisted reproductive technologies for Canadian snakes
Bibliographic record
Abstract
Assisted reproductive technologies (ART), frequently used to manage domestic livestock, are increasingly incorporated into conservation mating programs for species-at-risk. Species-specific insights on reproductive biology, including seasonal variation and endocrine function, improve ART outcomes. Despite representation in many zoological collections, snakes are underrepresented in the ART literature and research is needed before it can be broadly implemented in conservation. My research characterizes temporal variation in spermatozoa quality and sexual steroids for two endangered Canadian snakes to facilitate gamete cryo-preservation and artificial insemination. These focal species have different life history strategies: an oviviparous viperid, the eastern massasauga rattlesnake (Sistrurus catenatus) and oviparous colubrid, the gray ratsnake (Pantherophis spiloides). I collected spermatozoa samples monthly from May to October in 2023 and 2024 from individuals of both species held in captive population. Spermatozoa samples were quantified for concentration, motility, membrane integrity and rapid forward progression of spermatozoa. I predicted the highest concentration and quality spermatozoa would be produced during the period corresponding to the mating season in wild population; late July through August in rattlesnakes, and late May through June in ratsnakes. I found species-specific variation in quality and concentration of spermatozoa, but not during the intervals predicted. To characterize the reproductive hormone cycle, faeces from captive rattlesnakes was collected from March 2023 to September in 2024. Sexual steroid faecal metabolites of progesterone (FPM) and testosterone (FTM) were quantified using commercial enzyme-linked immunosorbent assay kits. I predicted FTM concentrations would be highest from July to August, corresponding to spermatogenesis and the peak in mating behaviour. I predicted that FPM would increase in May and June during vitellogenesis, be expressed in the highest concentrations annually from May to August and remain at high concentration through to parturition in gravid females. I found annual variation in FTM and FPM, but not in the patterns which I had predicted. My research provides novel insights into the reproductive physiology of two Canadian at-risk species and facilitates efforts to develop ART in managed population. The integration of this information into conservation programs will improve fecundity, ensuring that captive population can best contribute to conservation.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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".