Old world versus new world: life-history alterations in a successful invader introduced across Europe
Bibliographic record
Abstract
We examined differences in pumpkinseed (Lepomis gibbosus) life-history traits between native North American and introduced European populations, and tested three life-history predictions related to the effect of temperature, growth, waterbody size, and the presence/absence of predators on native and non-native populations. Pumpkinseed populations exhibit more 'opportunistic' traits (earlier maturity, smaller size at maturity, and higher reproductive allocation) in their introduced European range than those in their native range. Predictions of life-history traits were improved when indicators of juvenile growth rate (mean length at age 2), waterbody size (surface area), and thermal regime (air temperature degree-days above 10 °C) were incorporated into models along with continental location, but European pumpkinseed populations exhibit more opportunistic life-history traits than North American populations even when these factors are accounted for. Native pumpkinseed in waterbodies containing piscivores mature later and at a larger size, and have lower gonadosomatic indices than those in waterbodies lacking piscivores, whereas there is no significant difference in the same three life-history traits between European waterbodies containing or lacking piscivores. Because congeneric competitors of the pumpkinseed are absent from Europe, the apparent absence of a predator life-history effect there could also be due to the absence of the major sunfish competitors. In either case, the evolution and maintenance of more opportunistic traits in European pumpkinseed can likely be attributed to enemy release, and this may explain the successful establishment and spread of pumpkinseed in many parts of Europe.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.035 | 0.008 |
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; both teacher heads agree on what is shown here.
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".