The Preferences of Lumbricus terrestris Earthworms for Weed Seeds Typical of The Canadian Agricultural Ecosystems
Bibliographic record
Abstract
Earthworms are post-dispersal seed predators that can potentially play an important role in regulating weed communities in temperate agroecosystems. Recent studies have found that seed feeding by earthworms tends to be driven by the active selection of certain seed species instead of random encounter. However, mechanisms that drive this active selection of certain seed species remain understudied in the literature. Numerous physical and chemical seed traits are expected to influence seed choice decisions by earthworms, including seed size, shape, coat hardness, nutritional content, and chemical defenses. The impact of these traits on seed selection by earthworms tends to vary depending on seed species identity and earthworm species identity, rendering the outcome of earthworm-seed interactions hard to predict. In this thesis, I carried out a series of experiments to study the impact of seed physical and chemical traits on seed choice by the anecic earthworm species Lumbricus terrestris L. Seeds of six weed species, Sinapis arvensis L., Thlaspi arvense L., Capsella bursa-pastoris (L.) Medik, Galium aparine L., Setaria viridis (L.) P.Beauv and Amaranthus retroflexus L. were offered to L. terrestris in multiple-choice feeding arenas to identify which seed traits would be of major influence on seed choice. Synthetic diets featuring three different protein-to-lipid (P:L) ratios and different protein quality levels were also prepared to study the nutritional basis of seed choice by L. terrestris. The multiple-choice feeding bioassays showed that seed selection by L. terrestris earthworms was mainly influenced by the lipid content of the seed when seed physical traits (e.g. size, shape, coat hardness) varied within certain limits. Furthermore, experimenting with synthetic diets showed that L. terrestris earthworms are mostly likely lipid-limited, and tend to consume seeds rich in oil to address the scarcity of lipids in their environment. Low-quality protein at low to intermediate levels did not seem to constrain the choice by L. terrestris regarding the acquisition of lipids from synthetic food. Additionally, the hydration state of seeds was found to influence the palatability of the seed to earthworms, with seeds imbibed for longer periods of time becoming increasingly more preferable to L. terrestris. The findings of this study bridge significant knowledge gaps in the literature, as seed nutrients emerge as an important driver of seed choice by L. terrestris earthworms when seed physical traits are within certain limits, but further research is needed to test if the same factors drive seed feeding by epigeic and endogeic earthworm species.
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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 | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 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) | 0.003 | 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".