Male amphipods increase their mating effort before behavioural manipulation by trematodes
Bibliographic record
Abstract
Certain parasites appear to alter the behaviour of intermediate hosts, making them more susceptible to predation by final hosts (adaptive parasite manipulation). In some cases, however, hosts are expected to respond by increasing their reproductive effort when first parasitized (adaptive host response). We tested predictions of these two hypotheses for males of the amphipod Corophium volutator (Pallas). Consistent with adaptive parasite manipulation, males infected by the trematode Gynaecotyla adunca (Linton) were likely to crawl on the surface of a mud flat, but only when visual predation by the final host, semipalmated sandpipers, Calidris pusilla L., was likely (during the day), and after trematodes had developed to their infective stage. Males appeared to compensate for parasitism by being more likely to mate, and perhaps by increasing ejaculate size. However, parasitized males that mated when first infected were less likely to mate again once their parasites reached their infective stage, despite their increased crawling at that time, which is associated with mate searching. We did not find that trematodes reduced host survival, apart from expected increases in predation rate on amphipods; in fact, highly infected amphipods actually lived longer than lightly infected ones. Taken together, our results suggest that adaptive host responses can occur before parasite manipulation is realized.
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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) | 0.022 | 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".