This is

This is Scientific Americans 60 Second Science.

I'm Karen Hopkins.

This will just take a minute.

Why did the tiny nematode worm cross the road?

Well, for all the usual reasons, but a more interesting question is how did it make the crossing?

Turns out, it may have hitched a ride inside a slug or other invertebrate.

That's according to a study in the journal BMC ecology.

Nematodes are about a millimeter long, and they're often found on decomposing fruits or rotting plants,

where they feast on the resident bacteria.

But when that food source is exhausted,

how do these diminutive diners make their way to the next meal,

which could be in a mulch pile a major trek of several yards away?

To find out, researchers hit the compost heap and they collected some

600 slugs and 400 centipedes, spiders, beetles, flies, and locusts.

And they found that the innards of slugs, centipedes, and wood lice are littered with live worms, that the larger

creepy crawleys accidentally ingested as they snacked.

But what becomes of these itinerant intestinal interlopers?

To solve that mystery, the researchers exposed 79 slugs to more than a million nematodes

that had been tagged with a fluorescent marker. And they saw that the worms not only survive a

southbound trip through a slugs guts, they emerge, none the worse for where they've been,

when their ride takes a bathroom break. Sure, a chugging slug isn't exactly high-speed rail,

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