Ecological Pathways: Poisonous Slugs
No-till farming (not plowing and harrowing and disking the land frequently), benefits field and forage crop production by reducing soil erosion, Garden Slug conserving water (if irrigation is necessary), improving soil health, and reducing fuel and labor costs. It’s generally a ‘good thing’ to do.
Neonicotinoids are the most widely used insecticides, worldwide. They are systemic insecticides applied to seeds to prevent ‘feeding’ damage by early season insects. “Systemic” means that the insecticide enters into the actual cellular structure of the plant—including nectar and pollen. These insecticides are very successful against insects (and a number of other organisms, not to mention pollution of surface waters—but we won’t go into all that at the moment).
Dead ground bettle
Slugs thrive in the stable environment provided by no-till practices, and feed on duff and young green plants. Now, slugs are mollusks, not insects, so they are not susceptible to the insect specific poisons. But by chewing on the young plants, and ingesting the insects who have taken in the insecticides, slugs accumulate the toxins in their bodies—they become poisonous. Then, the insects that eat slugs, mostly predaceous beetles (who also eat other “pest insects” like aphids, but we won’t go into that just now), are poisoned.
It’s not yet clear what happens to frogs when they ingest the toxins accumulated in slugs, or birds when they eat the bugs. Hard to tell when they have tummy aches or are feeling not so great. The research did show that, in the field, plots with neonicotinoid-treated seed had fewer insects and predators, more slugs, and lower yields than plots without the insecticides.”