Slugs and Nematodes: A Symbiotic, Megabus-Like Relationship?

Ever looked at a slug and thought: Nice public transport, wot? Quite possibly not, but small worms hitch rides on slugs and other invertebrates, researchers have found. They made their report recently in the journal BMC Ecology.

Here's how it works. Nematode worms (including Caenorhabditis elegans), which are about a millimeter long and often live on decomposing fruit or rotting plant material, often need to move to new locations. Researchers have found that they're traveling long distances by using other creatures' locomotion, according to the report. 

The researchers dissected and analyzed by microscope around 600 slugs and 400 invertebrates (flies, centipedes, spiers, beetles and locusts). Their study found that nematode worms are commonly found in slugs, woodlice and centipedes. When the invertebrates were feeding on rotting plant material, the worms invaded slugs' digestive organs. Part of the study involved tagging worms fluorescently, then doing a microscopic analysis of dissected slugs, a release said.

Basically, the small worms survived in the intestines, and were excreted alive with the slug feces, the release said.

In other words, kudos to the survivor nematode: "Our study reveals a previously unknown nematode lifestyle within the guts of slugs. The worms appear to have evolved to persist in the harsh environment of slug intestines, similar to a symbiont or even a parasite," says lead author Hinrich Schulenburg from Christian-Albrechts-Universität, Germany, in a release.

Basically, the worms are able to "travel" via slug or invertebrate for a day at a time. Scientists believe that they likely enter the intestines of other invertebrates after that.