January 2010

Just a quick interlude from a book I recently finished reading. It wasn’t a gardening book by any means, but in one tongue-in-cheek section the author describes the behaviour of a nematode, Heterorhabditis bacteriophora, that is parasitic on insects but has a symbiotic relationship with a bacteria. I mention it here because the section refers to gardeners, because the worm is a bit of a gardener itself and because it made me smile.

Isn't it cute? This is a different one: Necator Americanus

H. bacteriophora has taken up farming of sorts.  As it grows, it  nurtures a particular bacteria in its gut. Once it reaches the third of its four juvenile stages, it sets out to find a ‘host’ insect. The worm enters the insect – through an orifice, or by breaking in through the insect body – and makes its wormy way to the insect’s body cavities. When it’s found a nice spot, it ‘plants’ the bacteria (ejecting them by vomiting or defecating, in case you weren’t enjoying this enough.) The released bacteria get to work on replicating – both feeding the growing nematode and killing the host. Once that’s done, our nematode friend gobbles up both its herd of bacteria and the insect corpse that the bacteria have kindly helped digest, before laying eggs so that the whole merry cycle can continue.

Since reading about this process, I’ve also learned that many of the eggs hatch inside the mother nematode, and the youngsters destroy the mother as they grow.

The author concludes: “Such natural means of pest control are preferred to chemicals by many gardeners who pride themselves on their sensitivity.

None of the animals involved in these extraordinary patterns of behaviour has a brain of course. *

*Except perhaps the gardeners”


  • You may have used the little fellas to combat pests such as Asparagus beetle or weevils.
  • The book is about Caenorhabditis Elegans, which you might find in your compost heap. Elegans is named for its graceful undulating movement, and “lives in tranquil obscurity underground, parasitising nothing, eating only bacteria and slime mould.”
  • Other fascinating trivia on nematodes from the book: “A healthy worm defecates about every 45 seconds all its life.” 80,000 species of nematode are known but there may be 10 or 100 times more. Of the known, one lives in seals’ kidneys and can grow to 40″ long and “three  species can live in the rectum of the American cockroach.”
  • The book is called In the beginning was the worm. Finding the secrets of life in a tiny hermaphrodite, by Andrew Brown. It really isn’t a gardening book. It’s about the decades of study of C. elegans and about the scientists who did the work – work which had a huge impact of modern biology and on the sequencing of the human genome. I loved it: it’s written passionately, bringing in all sorts of different insights, with some wry humour and well-drawn character studies, and some sections of beautiful prose. I think it’s generally accessible, though coincidentally I read the first sections on genetics just after some study on the subject, so I don’t know how I’d have found it before. There are fascinating reflections on what drives scientists; the funding of scientific research; independence of thought, the commercialisation of knowledge and on what it means to be human. All of this makes it a rollicking good yarn despite a long middle section on who did what when, which seemed to lose some focus and structure, as well as some shoddy editing: perhaps there was a rush to get it out after the worm scientists received their Nobel Prize.

After many plantless years, I thought having a patch of mud to grow a few herbs and perhaps the odd tomato would be enough to satisfy me. Instead, the last few months have fed an apparently insatiable hunger and I’ve accumulated a list of new plants to try that would fill a rather larger outside space than the one available to me. But I have no self restraint, so have ordered them all anyway.

Here’s the first, perfect for the rather snowy winter we have in the UK at the moment: Rubus arcticus – the arctic bramble, or Nagoonberry.

At the moment there are a just a few tiny shoots in a very small pot of mud.

But this is what those little shoots promise:

It’s a pretty little plant. It only grows about 30 cm tall, with pretty pink flowers and is cold tolerant.

But never mind that. It grows BERRIES.

I will need to write an epic poem to do justice to how much I love berries. Berries are so delicious and sensual and sweet and amazing I feel like I’m having some sort of epiphany every time I eat one. Berries unhinge me.

(Normally I think I’ve got that awkwardly polite thing going pretty strong. I blame Claire and Julia. Paragons of virtue who lived over the road from me for a while as a child and always said please and thank you. Obviously that’s a good thing to do, but hearing about their goodness every day in my formative years left me feeling rather inadequate, and 20 years later their spectres haunt me in social situations. I constantly expect to be told off.

I wish I’d pulled their hair and put worms down their backs when I had the chance.)

But berries were always too nice for manners. In ‘pick your own’ fields I risked everything to meet my objective of eating more in the fields than I took home with me. Of course I was highly skilled in furtive scoffing to reduce the risk of reprimands, but I still felt like I was risking everything I held dear.

Wild strawberries obsess me: I only ever find the odd handful at one time, and when I do there’s no sharing. Just scoffing and then denial that they were ever there. I developed a good eye for spotting plants and wildlife purely to track them down and satisfy my greed.

Blackberries make me weep with joy. I know the best spots to find them and I’m not telling you where they are.

My parents built a fruit cage, and I think it was to keep me out.

If you come round for tea I will let you have the last piece of pie and finish off the bottle of wine, but I will not give you a fair portion of the fruit salad. I will also have eaten half the fruit before you turned up and will have a back up portion in the fridge to eat when you’re gone.

I’m not ashamed to say this. There’s no way you will like them as much as I do, so there’s no point wasting them on you.

The arctic bramble won’t satisfy my hunger. I will never be able to make myself sick from a harvest.*

From a little internet browsing it sounds more like my alpine strawberries: instead of a short season yielding glorious bucketfuls, it will offer up a few fruits regularly over a few months – a few tiny bursts of unearthly sweetness each day, hopefully late into the year. But that’s pretty good.

Just look at this picture. This berry is made for joy.

And here’s some more berry porn. It doesn’t normally last long enough for a photograph.

*Actually, although my mother has always told me I’ll make myself sick if I eat too many berries in one sitting it’s not true. I’ve tried, and there’s no such thing as too many berries. If you’d like to test my theory, please bring me a huge heap of berries and I will prove myself. Ideally I’d like 52 volunteers, each to bring me a huge heap of berries, with one coming round every saturday afternoon.