Native generalist natural enemies and an introduced specialist parasitoid together control an invasive forest insect
Bibliographic record
Abstract
Specialized natural enemies have long been considered a major force driving the population dynamics of outbreaking forest insects. While research has traditionally focused on the role of specialist parasitoids, recent studies and reviews reflect an appreciation of complex interactions among many regulatory factors. The sources suggest that specialist parasitoids and generalist predators can each inflict strong top‐down effects and that specialists and generalists can interact to regulate insect herbivore populations. Here we use the model study organism winter moth (Operophtera brumata) in its invasive range in the northeast United States to investigate interactions between the introduced, host-specific tachinid parasitoid Cyzenis albicans and native, generalist pupal predators. Prior research in Canada showed that predation of winter moth pupae increased after C. albicans establishment. To explain this phenomenon, the following hypotheses have been suggested: (1) parasitoids suppress the winter moth population to a density that can be maintained by generalist predators, (2) unparasitized pupae are preferred by predators and thus experience higher mortality rates, or (3) C. albicans sustain higher predator populations throughout the year more effectively than winter moth alone. We tested these hypotheses by deploying winter moth pupae over six years spanning 2005 to 2017 and by modeling pupal predation rates as a function of winter moth density and C. albicans establishment. We also compared predation rates of unparasitized and parasitized pupae and considered additional mortality by a native pupal parasitoid. We found support for the first hypothesis; we detected both temporal and spatial density dependence, but only in the latter years of the study when winter moth densities were lower. We found no evidence for the latter two hypotheses. Our findings suggest that pupal predators have a regulatory effect on winter moth populations only after populations have been reduced, presumably by the introduction of the host-specific parasitoid C. albicans.
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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".