Butterflies are fun to raise and if you go about it properly it is not to difficult, 4 species for whom the rearing methods are very similar are, the Peacock (Inachis io) the Red Admiral (Vanessa atalanta) the Small Tortoiseshell (Aglais urticae) and the Comma (Polygonia c-album). All of these are common spring or early summer butterflies and have larvae that feed on Stinging Nettles (Urtica dioica). They all hibernate as adults over winter, though the coma is restricted to the South and Red Admirals rarely survive the winter, though some do in Devon and Cornwall at least, and they arrive regularly from the continent every Spring.
Before you go looking for butterflies though you will have to get your cage and food plants sorted. The most satisfying way to raise the caterpillars is from eggs you have watched being laid on live plants. For this you will need several large plant pots (about 25-35 cms across) and a healthy collection of Nettle (Urtica dioica) roots or plants cut off near the ground. Fill the pots to within about 10 cm from the top with topsoil and or compost, plant the nettles on this and fill the pot to about 2-3 cm from the top. You will also need 5, 120 cm Bamboo canes per pot, these should be pushed into the soil right to the bottom of the pot, and evenly spaced around the edge of the pot. Leave these outside covered with a sack until next Spring, they should start growing then and may need watering occasionally as the soil in the pots will dry out faster than the soil in the ground. You will also need about 0.5 of a metre of fine black mesh, this can be bought from Watkins and Doncaster, Maris House Nets and a number of Butterfly Houses. In the Spring wrap the mesh around the outside of the poles, tie firmly at the top and hold the bottom of it to the top of the pot with some elastic, this will allow you access.
You can buy butterfly eggs from a number of Butterfly Houses, you will have to look in the Yellow Pages as I do not know them all, if you want to buy some. The nicest way is to either find your own eggs in the wild and transfer the caterpillars after they hatch or to catch some butterflies and keep them under the mesh until they mate and lay eggs. Note that though both sexes look the same the males will be the ones holding territories and flying up to investigate everyone, the females will be not holding a territory, though for the first couple of weeks they will be all looking for food. You will have to feed your Butterflies an artificial nectar, a 10% mixture of honey in water will do. You can give this to the Butterflies by soaking a piece of cotton wool in it and placing it on the top of the mesh. As this dries out do not just rewet it because the water dries out and the honey doesn't thus it will get more and more concentrated becoming harder for the butterflies to sip and likely to cause digestive problems. They all will only lay in bright sunshine, and they all take several weeks to reach sexual maturity. If you are lucky you will see both the mating and the egg laying, you can then let the Butterflies out again.
If you have bought or collected eggs you will need to either, keep them in a small container with as little vegetation as possible, if you open the container once a day and breath on them a few times this will keep them humid. When they hatch transfer them very carefully to the Nettles with a fine paint brush, where about you put them on the plant will depend on the species, see notes below.
The Small Tortoiseshell, lays the eggs in clumps on the underside of the leaf and take about 10 days to hatch. When they hatch the larvae go straight to the top of the Nettle plant where they live together in a silk web until they reach their third instar, then they tend to become solitary, rolling up one or two leaves to live in they take about a month to grow to full size. They will pupate at the top of the mesh and emerge about 14 days later.
The Peacock, lays the eggs in clumps on the underside of the leaf and take about 14 days to hatch. When they hatch the larvae live together in a silk web until they reach their third instar, then they tend to become solitary, rolling up one or two leaves to live in they take about a month to grow to full size. They will pupate at the top of the mesh and emerge about 14 days later in late May to early June with a second brood in late July.
The Red Admiral, lays eggs singly on the topside of the leaf, when it hatches the larva it roles up a leaf to live in, making a new one when this is eaten out. They take about one month to grow to maturity and be ready to pupate.
It is a good idea to release the Butterflies close to where you found their parents.
For more about Butterflies see the main Butterfly Page.
Breeding butterflies and Moths, by Ekkehard Friedrich