Butterflies! While many turn away in disgust at the thought of some invertebrates, butterflies are widely embraced perhaps because of their majesty and aesthetic charm.
We often see them in the warmer months floating about as they search for delicious nectar or plants on which to lay their eggs, buthow much do we really know about them? Particularly our native species here in New Zealand.
As is common to isolated islands, New Zealand has a relatively low diversity of Papilionoidea (butterflies) compared to other parts of the world with around 25 species of butterfly including migrants and introduced species. Seventeen of these species are considered native to New Zealand. To compare, the British Isles which is a temperate area and of equivalent size to New Zealand, has 59 species of butterfly.
Excluding the need for the correct climate/habitat, butterflies require two things to complete their lifecycle.
Host plants for their caterpillars to feed upon and of course nectar to feed on themselves. The host plant is a plant on which butterflies lay their eggs and which their caterpillars will feed upon before forming a chrysalis and metamorphosising into butterflies.
The plant selected as host is entirely dependent on the species in question. As an example the monarch butterfly (Danaus plexippus) which most of us know well, commonly uses the swan plant as its host but can use other milkweed species also.
For nectar, butterflies of all varieties seek out nectar-rich flowers. Marigolds, dahlias and cosmos are all good options for the garden.
But don’t forget about our native species, they can do the job too. Good species for this include lacebark, hebe, mānuka and even kōwhai may get the occasional visitor. So, what butterfly species do we have here in Northland?
Australian Painted Lady butterfly Vanessa kershawi resting. This type flies similar to our native admiral species of butterflies.
I’m sure most of us are familiar with the pesky cabbage white butterfly (Pieris rapae) the caterpillars of which chew up our cabbages to no end! And of course, the monarch butterfly with its distinct orange and black wings, commonplace on a warm sunny day. But did you know other species are present here too?
We can break this down into a few groups, migrants, admirals, coppers and blues. As the name suggests migrant butterflies are those that migrate here usually from Australia on prevailing winds but have not been observed overwintering here in New Zealand. Species include painted lady (Vanessa kershawi), blue moon (Hypolimnas bolina nerina) and more rarely blue tiger (Tirumala hamata hamata). These species do not breed here; however, they are a beautiful remarkable sight if you are lucky enough to spot them.
Admirals, on the other hand, are native to NZ and are present in Northland in low numbers.
We have two species, the kahukōwhai or yellow admiral (Vanessa itea) and the kahukura red admiral (Vanessa gonerilla gonerilla) the latter of which is endemic to New Zealand meaning it cannot be found anywhere else globally. Kahukōwhai prefer more open habitat including parks, gardens and farmland whilst kahukura prefer native forest but will venture into open habitat also. Both these species use stinging nettles as their host plant which is low abundance throughout the North. This undoubtedly contributes to the small number of these species in the region.
Copper butterfly on host plant Muehlenbeckia found on Ruakaka coast.
The copper butterflies, also native, are an interesting group, believed to be in an active state of evolution. There are currently four recognised species but due to the sheer number of “forms” it has been proposed that there may be as many as 25 species which remain mostly unnamed. Two of these species can be seen in Northland the Maui’s copper (Lycaena edna) and the North Island coastal copper (Lycaena salustius) which is seen quite commonly in coastal areas. These species aren’t overly uncommon in areas where the host plant pohuehue/mulhenbekia is abundant.
The blue butterflies including the common blue (Zizina otis) and the long-tailed blue (Lampidies boeticus) are believed to be self-introduced residents, however some debate this! These species occur commonly throughout the region preferring open habitat such as lawns, farmland, and garden areas. The host plant for these species are legumes, particularly those of the pea family.
As with most native species our butterflies have several threats. Predatory wasps and parasitic wasps prey upon caterpillars, habitat change/loss has restricted their natural range, the loss of host plants is preventing successful reproduction, and the widespread use of insecticide has had a detrimental effect on many species also.
But not all is lost, we can all do our part to help these amazing creatures. You can plant either host or nectar plants in your garden, both would be even better. You can limit the use of insecticides in your veggie patch, covering produce with insect nets or planting marigolds nearby is a great way to keep pests at bay. You can investigate wasp control options suitable for your needs. Killing nests when you find them is good for a myriad of reasons in addition to helping butterflies.
Currently the conservation and native species team (CANS) at KiwiNorth are working on a butterfly project which includes monitoring of butterfly and moth species on site, creating quality butterfly habitat and inspiring the public to get involved and help these often overlooked and undervalued species. If you are interested in learning more or contributing to this project in any way, please contact CANS@kiwinorth.co.nz
Bevan Cramp is the keeper, conservation and native species team, Kiwi North.
