Environmental parasitology of trematodes, snails and larval amphibians
Bibliographic record
Abstract
Environmental influences on trematode parasite infection in larval frogs may be mediated through effects on the frog hosts, other hosts in the parasite life cycle, or on the various life history stages of the parasites. Herein, I investigated effects of corn agriculture and landscape characteristics on trematode infection in both snails and tadpoles, and report that both affect infection patterns seen in these first and second intermediate hosts. Tadpoles from ponds adjacent to corn fields exhibit a higher prevalence of infection, whereas snails from such ponds show the opposite pattern. Landscape features likely exert an influence via habitat suitability for the definitive hosts. I also examined the impact of the herbicide atrazine (commonly used on corn crops) on the free-living cercarial infective stage of trematodes. Mortality, activity and infectivity are reduced in some species; however, when tadpoles and cercariae are exposed to the same concentration of atrazine, increased host susceptibility can be countered by detrimental effects on cercariae. This demonstrates the importance of examining the effects of an environmental factor on all aspects of a parasite life cycle. In addition to physiological or immunological effects, environmental perturbations may affect host susceptibility to trematode infection through behavioural alterations. I demonstrate that tadpoles exhibit an effective anti-parasite behaviour and that suppression of this activity results in an increase in trematode parasitism. The impact of trematode parasitism for natural frog populations was examined by investigating the interaction of infection with competition with conspecifics, a common stressor for tadpoles. Trematode infection and high rearing density had an additive negative effect on tadpole growth and development; effects were likely mediated by parasite-induced changes in resource allocation. The pattern of trematode infection observed in natural tadpole populations is thus the result of many factors, including those affecting host susceptibility (behavioural and immunological), cercarial infectivity, and abundance of definite hosts.
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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".