Roundworm

The little worm squirts milk from its vulva to feed its offspring

By Michael Marshall

Nematode worms (Caenorhabditis elegans) can produce a type of milk

Science Photo Library / Alamy

A MICROSCOPIC worm that has been studied by biologists for decades has hidden a secret: it can make milk to feed its young – in a way that supports the idea that aging is programmed and not programmed by evolution is just an accident.

The nematode worm Caenorhabditis elegans is used in many biological studies each year, but David Gems of University College London and colleagues are the first to notice that the worms, some of which are hermaphrodites, leave smears of …