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16 january 2024

While I was reading Kevin Butt's new book Worm, I ran across a story from the Australian Broadcasting Corporation about a huge swarm of worms that accosted a fisherman and his daughter. '"They just kept coming—more and more just kept coming out of the mangroves" … While pulling up one of the crab pots, his daughter bumped one of the worms and it "literally just fell apart" with green goo "spewing out of it".' (www.abc.net.au/news/2024-01-14/). These Australian worms may be hitherto unknown to science. Butt explains that a lot of things about worms are unknown to science, despite the ubiquity of worms and a recent uptick in worm research.

Nothing can make a green-goo worm swarm seem like a positive thing, but Butt's book changed one of my ideas about worms for the better. After a rain, earthworms will rise to the surface of lawns, and sometimes get stranded on concrete or other pavement. I always throw them back onto lawns, but I felt bad about it because I assumed that rain washes worms out of their burrows; either way, I thought, the worms will have a bad time of it. But no, Butt says that worms love water and will happily re-burrow into waterlogged soil. They come to the surface after rain, not because they're flooded out, but because all the water gives them an opportunity to stake out new territory. Toss those worms anywhere soft, then – apparently, they love it.

Familiar as they are, much remains unknown about worms because they live invisibly to us, though they're literally underfoot. Worm taxonomy is a parlous business, says Butt. There are myriad species; many of them look alike; folk categories mix iconic annelid worms together with insect larvae, snakes, legless lizards, and amphibians like the caecilians. Even among true worms, a given ecosystem will include those that live on the surface among litter and compost, those that plow through the immediate topsoil, and those that burrow several meters down.

Much of Worm is devoted to Charles Darwin, who in addition to founding everything else about modern biology, was the great patron scientist of earthworms. The Formation of Vegetable Mould (1881) remains one of the foundational texts for the study of worms. Oddly enough, Darwin was largely incurious about worm taxonomy. For him, the mass of different worms at work on the soil was not of interest at the individual or even the species level. Darwin had an amazingly capacious sense of how an entire biota could interact with, indeed construct, its environment. Like beavers with their dams, earthworms build their habitat out of the raw materials of clay and plant detritus.

I am always struck, when reading about archeology, by the insistent way in which time buries human artifacts. We don't necessarily throw much stuff on top of old junk, ourselves. Instead, soil accumulates over our traces seemingly of its own accord. But there's no magic to it; it's the worms at work. Butt recounts how he and a team of researchers replicated some of Darwin's observations (87-89, 92). Darwin returned to a cleared but unplanted, flinty field in his neighborhood, at intervals over the space of several years. At first it was just a rockstrewn plain. Gradually, though, soil rose over the rocks, so that "a horse could gallop over the compact turf … and not strike a single stone with his shoes" (88). Over a century later, Butt laid stones on the same field, and sure enough, the same forces inexorably buried them.

Some kinds of parasitic worms can inhabit our living bodies, but do common earthworms munch on us after our demise? Butt is not so sure. Bodies laid six feet deep – especially if encasketed and embalmed – are unlikely to be affected by true worms, which live much closer to the surface. But worms will eat lots of things (Darwin noted their attraction to fats), and probably, yes, some human bodies become the proverbial worm food.

Can we, in turn, go eat worms, as a children's song suggests? Earthworm protein is bland and nutritious. Wormmeal has been baked into things like "Applesauce Surprise Cake" (64), though alas, Butt does not give the recipe. Since worms are everywhere, one imagines they could become an important source of human food. But as with edible insects, there are problems of scale. There's not much food on a worm, and the costs in energy, land, and resources needed to grow worms for direct use as food probably don't merit the effort.

Worms can be an important crop, all the same. Bait-worms are gathered by the hundreds of millions in Canadian fields. I first learned about this industry in Souvankham Thammavongsa's story "Picking Worms," in which Laotian immigrants make a tenuous living at the abject task of scooping earthworms from the ground.

Worms in poems and song are a minor theme in Worm. Butt finds the classic loci of worms: Hamlet providing the link between a king and "the guts of a beggar," in the form of a worm; Edgar Allan Poe's Conqueror Worm, William Blake's invisible worm, the worms that fueled Lord Byron's imagination. Butt mentions glow-worms, which are actually beetles but do come up in a lyric that Johnny Mercer added to an old operetta song:

Glow little glow worm, fly of fire
Glow like an incandescent wire
Glow for the female of the species
Turn on the AC and the DC
Which isn't correct; only the female glow-worm, little glow-worm, glows.

Kevin Butt explains wormy life-cycles and delves deep into the soil of popular culture for all kinds of horrific and cuddly worm imagery. Worm should become a landmark text in popular vermicology.

Butt, Kevin. Worm. London: Reaktion, 2023.