Stress and Parental Care in a Wild Teleost Fish: Insights from Exogenous Supraphysiological Cortisol Implants
Bibliographic record
Abstract
Male largemouth bass (Micropterus salmoides) provide sole parental care over a 4-6-wk period to a single brood, fanning the eggs to keep them oxygenated and free of silt and defending the brood until the offspring develop antipredator tactics. During this period, fish are highly active and have few opportunities for feeding, so this activity is energetically costly. To understand some of the consequences of stress during this challenging period, we injected fish with cortisol suspended in coconut oil to experimentally raise circulating cortisol in parental males for the first week of the parental care period. We compared parental care behavior between cortisol-treated, sham-treated (injected only with coconut oil), and control parental males. We further compared physiological parameters associated with metabolism and reproductive function between cortisol-treated and control males. The cortisol injections resulted in supraphysiological levels of circulating plasma cortisol, giving us insight into potential maximal effects of stress during parental care. At these supraphysiological levels, the cortisol-treated fish displayed higher concentrations of circulating glucose and cholesterol and lower concentrations of circulating triglycerides when compared with control fish, with no change in plasma concentrations of total protein. Plasma concentrations of androgen were similarly unaffected by cortisol treatment. In the short term (initial 1-2 wk), parental care of eggs and egg-sac fry was maintained by all groups, with no differences observed in behavior (e.g., tending, vigilance, defense) among the groups. However, the cortisol-treated fish abandoned their offspring at a higher rate than in the control or sham groups. The fish treated with cortisol also tended to develop external Saprolegnian infections, indicative of compromised immune function. These data demonstrate that exogenous cortisol elevation during parental care results in changes in energy use and a decrease in immune function. Interestingly, the data also suggest resistance to stress during parental care in largemouth bass, with no changes in parental care behavior before abandonment.
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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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".