Spatiotemporal variation in metacercariae prevalence and intensity for the host manipulator <i>Dicrocoelium dendriticum</i> in two species of wood ant from southern Alberta, Canada
Bibliographic record
Abstract
Abstract Exposure to certain parasites can occur when hosts encounter clumps of infective larvae during ingestion. Compared to more typical transmission pathways involving the cumulative penetration or ingestion of single larvae, clumped transmission can be expected to lead to complex and variable epidemiological patterns of infection within exposed hosts. We explored this idea in a spatiotemporal survey of wood ants ( Formica spp.) infected with metacercariae of the host-manipulating trematode, Dicrocoelium dendriticum. Ant second intermediate hosts are exposed to clumps of cercariae during ingestion of ‘slimeballs’ that are released onto pasture by land snail first intermediate hosts. In a total sample of >650 ants collected during the host-manipulation phase when ants were attached to plants, metacercariae prevalence was 97% and mean intensity was 27 ± 25 (range in intensity = 1–168; variance:mean ratio = 23.1). None of the observed variation in mean metacercariae intensity could be attributed to year (2021, 2022), month (May to August), or nest. Although the recruitment of metacercariae into ants occurred within a narrow window of transmission each summer, the mixed-age structure of our ant samples likely limited our ability to detect seasonal patterns of mean intensity. The absence of significant spatiotemporal patterns in metacercariae intensity in samples of ants likely also reflects infrequent and variable rates of encounter with cercariae-containing slimeballs by individual ants.
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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 | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 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".