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A few facts about butterflies

27 October 2021

If you grew up in New Zealand then chances are that you will recognise the monarch butterfly. In the 1950’s, when I was at primary school, every classroom had a Nature Table. Each Spring someone would bring in some monarch caterpillars on swan plant.

But here’s a few facts you probably never knew about them!

A few facts about monarchs

Did you know you can tell the difference between a male and a female monarch? It’s not so easy with other species of butterfly, but monarch males have two scent glands which appear like black dots on their hindwings. The veins on female monarchs are also thicker than on the male.


Here in NZ monarch butterflies are considered natives even though they originated in North America. They introduced themselves –in the early 1800’s, possibly earlier, they flew/blew here. In North America they make a spectacular migration each Autumn (Fall) from as far north as Canada to join millions of monarch butterflies in reserves in the mountains of Mexico’s Transvolcanic Belt. It is the most amazing migration to witness! Some butterflies have flown 5,000 kilometres!

Monarchs (Danaus plexippus), Michoacán, Mexico

A cluster of monarchs in the Sierra Chincua Santuario Mariposa Monarca, Michoacán, Mexico

NZ does not have a large number of butterfly species that they can call their own but we do have about 2,000 moths, of which over 90% are endemic!

All butterfly and moth species need two types of plants: The females of each species lay eggs on ‘host plants’, which vary depending on the butterfly. I think everyone knows that the cabbage white lays eggs on brassicas like your cabbages and cauliflowers. The monarch, of course, lays eggs on swan plants, so called because the seed pods resemble swans before they split open, the wind scattering their seeds.


Did you know that the swan plant originated in Africa? It is believed that quite possibly the seed arrived in NZ as a ‘stowaway’ inside a pillow, cushion or garment which was bought by settlers visiting ports on their journey here. The fibre attached to the seed has been used for many years as a stuffing material.

In fact, during WWII, when America joined the Allies, they needed kapok to fill thousands of Mae Wests (life preservers). As Indonesia was held by the Japanese there was no kapok available. So schools in the United States were called upon to send their students out into the fields to gather milkweed floss and it was actually found to have a better flotation score than kapok. This comic-style poster from 1941 tells the story - thanks to for sharing.

Wwii Comic Backyard Lifesaver

Nectar is sweet!

But I digress! The other type of plant that all butterflies need is a nectar source: bright, colourful flowers that are loaded with nectar. Butterflies are pollinators, like bees, so as they extend their proboscis deep into the centre of a flower they collect pollen which they then leave in another flower, allowing fertilisation of the flowers and in the end producing seeds or fruit. It is estimated that ¾ of our food depends on pollination!


2 comments on “A few facts about butterflies”

  1. I have had monarchs since my kids were little, this is the first year I have found a blue tinted one, do you know what this is

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