Wed Feb 14

NZ votes the red admiral butterfly ‘bug of the year’ – how to make your garden its home

Written by: Janice Lord, Associate Professor in Botany, University of Otago

New Zealanders traditionally show their love for a special other on Valentine’s Day, so what better time to reveal which insect they feel the most affection for?

The second annual Bug of the Year ^[1] contest has been won by the red admiral butterfly. It received a total of 2,275 votes from the nearly 17,000 votes cast by New Zealanders at home and abroad.

One of our most spectacular butterflies, the red admiral inherits the crown from last year’s inaugural winner, the native bee, or ngaro huruhuru (Leioproctus fulvescens).

While a butterfly beat the other bugs, the Mt Arthur giant wētā ^[2], the ngāokeoke (velvet worm) and the titiwai (glowworm) were close behind, with thousands of votes each.

The Entomological Society of New Zealand ^[3] began the competition to shed light on the underrepresented and stunningly unique bugs of Aotearoa New Zealand. As interest grows, it is hoped more people will be inspired to create and maintain habitats for these often-endangered species.

Aotearoa is home to over 20,000 different species of bugs – more correctly known as terrestrial invertebrates. They range from vibrant butterflies and iconic wētā to secretive velvet worms and carnivorous land snails. And those are just the species described so far.

There are ten times as many bug species in New Zealand than there are native plants, and over a hundred times more than native bird species. Yet most people don’t know much about them.

Glowworms inside the Waitomo Caves: close runners-up to the red admiral. Getty Images

Moths and butterflies aren’t so different

The red admiral is easily recognisable by its vibrant red and black wings. Its Māori name, kahukura, translates directly as “red cloak or garment”, but can also refer to the atua (deity) represented by the top bow of a double rainbow.

The closely related kahukōwhai, or yellow admiral, has similar colouring, except the underside of its upper wings is creamy yellow. Red admirals are endemic – only found in New Zealand – whereas yellow admirals are also native to Australia.

Aotearoa has over 2,000 species of lepidoptera – butterflies and moths – and roughly 90% of these are endemic. You might be surprised to know there are no clear differences between what are commonly called butterflies and those called moths.

Only 17 of our lepidoptera species are popularly referred to as butterflies. But many of the other 98% – so-called moths – are active during the day and can also be beautifully patterned and coloured.

Because they feed from floral nectar sources and transfer pollen in the process, moths and butterflies are important pollinators. They are also staples in the food chain, forming a large portion of native bird diets.

The native pūriri moth is nocturnal, but many moths are active during daytime. Getty Images

Gardens as butterfly habitats

Like many butterflies worldwide, red admirals are less common than they used to be. While recent gardening advice ^[5] has begun to include bee-friendly planting, it is also important to think of other invertebrates, like butterflies, when we plan and cultivate our backyards.

In general, a diversity of simple nectar-rich flowers is positively related to pollinator health ^[6]. And resilient and diverse pollinator populations benefit both natural and created ecosystems like gardens. In turn, they support biodiversity and overall environmental health ^[7] – which all benefits human welfare.

The Moths and Butterflies of New Zealand Trust conducts an online course ^[9] on how to assess, create and maintain butterfly habitats.

Lepidoptera differ from some other invertebrates in that females prefer to (or exclusively) lay their eggs on specific host plants. If preferred host plants are not available, caterpillar survival can be low.

So, while having a variety of flowering plants for adults to feed from is important, providing host plants for caterpillars to develop on is crucial.

monarch butterfly emerging from chrysalis

Monarch butterflies feed on milkweed, but other garden plants can attract native butterflies. Getty Images

It is well known that monarch butterfly caterpillars need to feed on milkweed (swan plant). Similarly, Muehlenbeckia species ^[10] such as climbing pohuehue and shrubby tororaro are important host plants for many native butterflies, as well as many native moths.

Lack of suitable hosts may be one reason red admirals are becoming increasingly uncommon. Recent research ^[11] has shown the females prefer laying eggs on native nettles, and larvae raised on native nettles outperform those raised on introduced nettles.

Experiments show that the tree nettle ongaonga (Urtica ferox) is an ideal host for red admiral caterpillars. But ongaonga is often removed due to its extremely painful stinging hairs.

Pollinator protection

Besides planting with butterflies and moths in mind, there are many other actions you can take in the garden to help make it suitable for thriving pollinator populations.

Some of the biggest threats ^[12] to insect populations in Aotearoa and the world are related to urbanisation, deforestation and agricultural intensification: loss of habitat and food sources, and pesticide use.

Introduced predators also threaten our unique bugs. Invasive vespula wasps ^[14] and rodents are a menace to native butterflies and moths. But predator control systems ^[15] such as backyard trapping can make a difference.

Future articles will offer seasonal advice on gardening and lifestyle practices to help bugs in your backyard. This will include the best times to spot native and introduced bugs, and other ways to promote invertebrate conservation and biodiversity.

Whether you’re already a bug lover or still a bit bug-tentative, it’s important we all help invertebrate populations in Aotearoa survive and thrive.

The authors gratefully acknowledge the help of the Moths and Butterflies of New Zealand Trust ^[16] in the preparation of this article.