Photoperiod Differentially Affects Immune Function and Reproduction in Collared Lemmings (Dicrostonyx groenlandicus)
Bibliographic record
Abstract
Many nontropical rodent species experience predictable annual variation in resource availability and environmental conditions. Individuals of many animal species engage in energetically expensive processes such as breeding during the spring and summer but bias investment toward processes that promote survival such as immune function during the winter. Generally, the suite of responses associated with the changing seasons can be induced by manipulating day length (photoperiod). Collared lemmings (Dicrostonyx groenlandicus) are arvicoline rodents that inhabit parts of northern Canada and Greenland. Despite the extreme conditions of winter in their native habitat, these lemmings routinely breed during the winter. In the laboratory, collared lemmings have divergent responses to photoperiod relative to other seasonally breeding rodents; short day lengths can stimulate, rather than inhibit, the reproductive system. Male and female collared lemmings were maintained for 11 weeks in 1 of 3 photoperiods (LD 22:2, LD 16:8, or LD 8:16) that induce markedly different phenotypes. Following photoperiod treatment, cell-mediated immune function as assessed by delayed-type hypersensitivity reactions was elevated in lemmings housed in LD 16:8 and LD 8:16 relative to LD 22:2. However, antibody production to a novel antigen was unaffected by photoperiod. Exposure to LD 8:16 induced weight gain, molt to a winter pelage, and in contrast to previous studies, regression of the male, but not the female, reproductive tract. In conclusion, these data indicate that components of immune function among collared lemmings are responsive to changes in day length.
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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".