Nettles

Nettles (Urtica dioica)

Nettles are a lot friendlier than you might think. It is true that they sting with a combination of histamine, serotonin, acetylene choline and formica acid with a few other chemicals thrown in, but they are kind to butterflies and even moths. There are five rather fine butterflies whose larvae feed on common nettles. They are the Red Admiral, the Peacock, the Small Tortoiseshell, the Comma and the Painted Lady. Then there are the moths - Burnished Brass, Snout and the Cream Spotted Tiger to name but three. In all 31, species of Lepidoptera feed on nettles and altogether about 40 species of insect. Stinging doesn't do them as much good you might think, but it is the mammals that the stings defend against. Rabbits, cows, pigs and sheep are definitely not keen. Goats will have a go and apparently there's no holding back donkeys.

There are six subspecies of the common nettle and one of them does not sting. If you are thinking of launching yourself naked into a patch, the odds are not good for coming out unscathed. Those that sting have tiny hollow silica hairs with a venom reservoir at the base. The hair easily snaps off in your skin and the sting is delivered as by a hypodermic needle. The British nettle may be painful and irritating but we are lucky. In Java there is one that can kill.

If you really dislike nettles you can get your own back by eating them. They are highly nutritious and contain vitamins A,C,D, iron, manganese, potassium, calcium and copper. All you have got to remember is to cook them to disable their stings. That is, unless you are in the Dorset nettle eating contest in which case you see how many raw ones you can eat. Alternatively you can makes cloths out of them using the fibres in the long stems like the Germans did for their army uniforms in the Second World War when cotton was in short supply. In addition the leaves yield a green dye and the roots produce a yellow dye.

Nettles are handy to the archaeologist because they like really rich soils such as are found near human settlements where we have dumped our sewage. Such locations are rich in nitrogen and phosphorous which nettles love. They use the nitrogen for their their young leaves which are rich in protein. This is why spring aphids feast on them and ladybirds feast on the aphids. Something that the nettle finds galling is that a small Cecid fly ( Dasineura urticae) attacks it's leaves and causes a pouch gall to be formed in which the fly's larva seeks to develop in safety. Sometimes it does and sometimes the hunter is hunted by another Cecid fly whose larva predates the first one. It's not all joy being a Cecid fly and perhaps you never thought it was.

Dasineura urticarae, a gnat, has caused a pouch gall on the nettle.

The patch of nettles in the garden is a positive menagerie and repository of nutrients that can be used to perk up the compost heap so why not grasp the nettle and leave them to enhance the ecosystem. 'Butterfly Conservation' will be grateful and spare a thought for the miserable nettle weevil which has a diet solely of nettles, something to make us all feel fortunate.