Optimizing Sex Ratios of <i>Hyalella azteca</i> to Reduce Variability in Reproduction and Improve Reproductive Toxicity Test Methods
Bibliographic record
Abstract
Standard toxicological test methods with Hyalella azteca incorporate both lethal and sublethal (growth, reproduction) endpoints, although lethal endpoints are often favored in routine testing. However, sublethal endpoints are important to consider because they are ecologically relevant and are often more sensitive than lethality. It is difficult to achieve robust data for reproduction in H. azteca because high biological variability is associated with reproductive yield, likely due to complex interactions in mate selection, which can add to the variability in brood sizes that females produce. In addition, effects on reproduction often co-occur with effects on growth, making it difficult to differentiate effects on growth from those on reproduction in standard tests initiated with juveniles. The present study characterized the reproductive capacity of H. azteca by investigating the role of sex ratios in reproductive yield. Experiments were initiated in the absence of toxicants with sexually mature (6-8-week-old) individuals that were placed in different female-to-male ratios (1:1, 2:3, 3:2, and 7:3). Reproduction was monitored during weekly static renewals for 7 weeks. The results indicated that a higher female:male ratio (seven females to three males) improved reproductive success and lowered biological variability in reproduction. In addition, the body lengths and weights of newly mature amphipods were used to create a size distribution to aid in the identification of small female amphipods. Based on the results of our study, a novel reproductive toxicity test method is proposed that begins with sexually mature amphipods in a ratio of seven females to three males to minimize reproductive variability in amphipods and to enable a more effective assessment of contaminants using reproduction as a highly sensitive endpoint. However, evaluation of this novel method with toxicants is needed to demonstrate that results are comparable to standard methods. Environ Toxicol Chem 2024;43:712-722. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".