Overwintering habitat and the success of the biocontrol beetle, Cassida rubiginosa Müller (Coleoptera: Chrysomelidae)
Bibliographic record
Abstract
The leaf-feeding beetle, Cassida rubiginosa, was introduced to New Zealand in 2007 as a biological control agent against the pasture weed, Cirsium arvense (Californian thistle, Canada thistle, creeping thistle). The beetle is now well-established in most regions of New Zealand, but outbreak population have only been observed in one region (Wairarapa). We hypothesised that overwintering habitat type might affect the survival of the beetle and its ability to achieve outbreak population densities. We tested the overwintering survival of C. rubiginosa in three different habitats: radiata pine forest, native New Zealand forest, and pasture, in a region where the beetle is not currently observed (Gisborne). In April (autumn) 2016, adult diapausing C. rubiginosa were placed in overwintering cages established in the three habitats, and in October (spring) their survival was assessed. For explanatory data, temperature and relative humidity was recorded in each habitat, and predatory spiders were also sampled. The total recovery rate of overwintered beetles was greatest in the native forest (42 ± 7.9%), followed by ungrazed pasture (32.5 ± 7.5%), and pine forest (7.5 ± 4.2%). The total percentage recovered was not significantly different between the native forest and pasture habitats, but both of these habitats had greater recovery rates than the pine habitat. The recovery rate of C. rubignosa decreased with increasing temperature and decreasing relative humidity. The native forest provided the best insulation against temperature and humidity extremes on a daily basis, and across the winter season, and is the likely explanation for the greater recovery rates in that habitat. Overall, spider abundance and species numbers in the test habitats were low, and did not appear to influence the overwintering survival rates. This study has provided initial evidence that the particular overwintering habitat available in New Zealand may contribute to the success of this biocontrol agent, and suggests that native forest with a leaf litter layer is likely to provide a better habitat than pine forest.
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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 | 0.000 | 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".