The picture shows two caterpillars which will one day be monarch butterflies. I found five caterpillars on my swan plant. One caterpillar is already quite fat. Soon it will become a chrysalis. The chrysalis is green at first but after about 2 weeks it becomes transparent and you can see the wings of the butterfly inside. Then the butterfly hatches from the chrysalis. The female mates with a male butterfly and lays eggs many times. The female can lay 300 or 400 eggs. When she finishes laying all her eggs, she dies.
At this time of year, you might be lucky enough to see a monarch butterfly. No, they are not native to New Zealand. Probably Europeans brought them here in the 19th century, along with some swan plant, also called milkweed. This is the only plant that the caterpillar will eat.
What happens to 300 or 400 eggs? I don’t know but predators like to eat fat caterpillars. Wasps and ants are predators. I can only find three caterpillars on my swan plant now. Maybe more are there but they are camouflaged and hard to see on the leaves.
The Monarch Butterfly Trust wants people to plant swan plants so that we have more monarch butterflies.
Vocabulary
• transparent –clear, we can see through it, like a window
• hatches – comes out of an egg or chrysalis
• predators – animals which eat other animals
• camouflaged – change colour to match the background so it is hard for predators to see them