An extremely rare form of monarch butterfly has been found in a Netherton, Waikato, garden... Not once, but two specimens, on the same day!

The nivosus morph is extremely rare around the world wherever monarch butterflies are found. Some years only one or two are reported, except for Oahu in Hawaii where up to 8% of the monarchs can be the rare, white form.

Scientists have undertaken research to show the nivosus phenotype segregates as a simple autosomal recessive trait. However, on Oahu the nivosus morph population has become reasonably stable. They have also been raised in a lab at Kansas University’s Monarch Watch.

“By eating milkweed such as swan plant, monarch butterfly caterpillars become distasteful to birds and most other predators,” says Jacqui Knight from the Moths and Butterflies of New Zealand Trust. “Monarchs have evolved to use this trait: predators recognise the bold orange wing pattern and link that to the bad taste. Predators will avoid them the second time.”

Knight says that the citizen science from raising monarch butterflies in the garden is a wonderful introduction to nature for NZ children.

“You can learn so much about nature... but also genetics, ecology, migration, maths, writing... Monarchs fuel our curiousity – and all you need is a swan plant.”

“This particular gardener was very fortunate to have found two nivosus monarchs. Before the tropical cyclone last week, she brought in as many pupae indoors that she could find on her plants, so that they wouldn’t get damaged during the storm. These two were some that emerged.”

Knight believes the white morphs will be reasonably safe from predation. “They should have the advantage because of their size and wing patterns, that a potential predator will still distinguish them as a monarch.”

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