High tolerance of two parasites in ornate tree lizards reduces the fitness costs of parasitism
Bibliographic record
Abstract
Abstract Parasites are ubiquitous and are presumed to have strong negative effects on host fitness. Despite this expectation, many parasites have negligible effects on their hosts in nature. Two hypotheses can explain why this might occur. Hosts can evolve resistance to parasites where their immune system attacks parasites (resistance hypothesis). The resistance hypothesis predicts that parasite load will decrease through time because of immune activity and that parasites have fitness costs to hosts. Alternatively, hosts can evolve tolerance to parasites and invest little energy in repelling attacks (tolerance hypothesis). The tolerance hypothesis predicts that parasites have no fitness costs to hosts. We tested these hypotheses with mark‐recapture data from six populations of a lizard host ( Urosaurus ornatus ) and two common parasites (ectoparasitic Trombiculid mites and haemoparasitic Plasmodium ). We found that parasite load was unrelated to lizard growth rates or survival. In addition, mite parasite load did not decrease through time. Thus, our data support the tolerance hypothesis. Ectoparasitic mites and haemoparasitic Plasmodium are therefore unlikely to be strong drivers of variation in Urosaurus ornatus population density at our study sites because of their negligible effects on host fitness. We encourage ecologists to measure carefully the effects of parasites on hosts, rather than assuming fitness costs of parasitism are present.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".