Nematode parasite species richness and the evolution of spleen size in birds
Bibliographic record
Abstract
Some of the interspecific variation in spleen sizes among bird species can be explained by interspecific variation in the proportion of birds infected by parasitic nematodes. Because prevalences of parasitic infections vary considerably in space and time within a host species, other variables may provide better measures of the selective pressure exerted by parasites on their hosts. For instance, the number of parasite species (species richness) exploiting a host population or species provides a more reliable index of the pressure exerted by parasites across generations. Among bird species, relative spleen size correlated positively with the species richness of nematode parasites exploiting a host species. This relationship was found after correcting for avian body mass (g), avian phylogeny, and sampling effort. A possible trade-off between investment in resistance against parasites and investment in reproduction was highlighted by a negative relationship between relative spleen size and relative testis mass. Parasitic nematodes could influence the trade-off, increasingly favoring investment in resistance as their species richness increases. The results of this comparative analysis and of previous ones suggest a causative role for parasitic nematodes in the evolution of avian spleen size.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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".