The good residents of Mayfair Grove, Alexandra, are proud of their gardens. In 2006, they won a Most Beautiful Street award for their ordered borders. But that was before Brian Patrick moved in. Because Patrick’s passion is butterflies, and he gets a charge from watching the little blues flit about the clover flowers on his lawn.
“Why would I mow all my clover flowers?” he says, sounding genuinely incredulous at the notion. Putting his case to the public, he erected a sign on his lawn, explaining to vexed neighbours that he was simply leaving some space for nature on his patch. “Butterflies don’t want everything all neat and tidy. They prefer things unkempt,” says the unrepentant director of Alexandra’s Central Stories Museum. “We have to leave a few wild corners…marginal habitats, roadsides, fallow paddocks.”
According to Patrick a manicured lawn is the enemy of our butterfly populations, and if he had his way, every garden would boast stinging nettle for admiral butterflies to feed and grow on, or a patch of “wild cabbages” for the introduced cabbage white; ironically, he says, “the only butterfly people might be familiar with”.
This is because very few native butterflies have adapted to our Eurocentric gardens. “In a typical Australian garden, you might have 25 species of butterfly; in New Zealand, you might get the odd copper or blue butterfly on the lawn, but they’re not occurring in the suburbs the way they should be.
“There were tonnes and tonnes of butterflies around when I was a boy,” he recalls, “but a lot of them have disappeared, because we’ve intensified [farming]; we’ve gone to extensive dairy, we’ve kept sowing fertiliser, we’ve kept changing things.
“We’re not nurturing butterflies. We’ve rolled back their habitats to the mountains.”
Others share Patrick’s view. In a semi-suburban quarter-acre at Russell, butterflies will also find sanctuary. Thickets of swan plants and stinging nettle, vivid nectar-bearing flowers and small, specially enclosed shade houses offer food and safe lodgings. Even Jacquie Knight’s one-bedroom home is largely given over to the protection and procreation of butterflies. Recently emerged monarchs hang from the sundry items of hardware and the host plants lining the verandah, flexing their crumpled wings that are still wet from the chrysalis. Whatever interior space isn’t occupied by food plants, host plants, mosquito netting (to protect her charges from parasitic wasps) and butterfly-tagging paraphernalia, is taken up by the office clutter of the Monarch Butterfly Trust, which Knight heads. It was originally formed in 2005 to protect one of the few known monarch wintering roosts in Northland from a residential development.
“Everybody in New Zealand knows the monarch butterfly,” says Knight. “If you asked the average New Zealander how many butterflies we have, they would say two; the cabbage white and the monarch. And after that, they’d be stumped.”
The trust intends to change that. While the monarch remains Knight’s abiding ardour, she’s now using the trust’s profile to advocate for the rest of our butterflies. “The monarch is now acting as an ambassador for the others,” she tells me.
For Knight, that means a ceaseless speaking tour; schools, gardening circles, women’s groups—any chance to convince people to leave a feral corner of the garden for admirals, coppers, blues. “People get rid of all the weeds and plant lawn instead. I think that’s crazy; we’ve got to get out of this mentality of having lawns, and let the butterflies breed.”
Before we felled the forests, tore out the Muehlenbeckia vines and planted crysanthemums, native butterflies graced every conceivable New Zealand habitat, and have always had a stronghold in the mountains. Alpine species comprise the bulk of our butterfly fauna, one of the reasons so few Kiwis have seen them.
The traditional view is that we have around 20 butterfly species; the tally is vague because they exhibit a bewildering fluidity of form. Debate rages, for instance, over the true numbers of coppers and mountain ringlets.
Just 12 butterflies have been formally described, and a burgeoning in-tray, combined with too few taxonomists, means we could be waiting a very long time for a grand total.
Like many other native groups, New Zealand butterflies are highly endemic, which is to say that more than 95 per cent of them are found nowhere else; one of the highest rates of endemism anywhere. The cabbage white, found throughout the country, was accidentally introduced. But the monarch arrived under its own steam, as did the yellow admiral and those little blues on Patrick’s lawn. Technically, that makes them natives.
Everything else—barring Australian wind-blown vagrants—is our own. This includes, for instance, the red admiral. Although other red admiral species range through temperate Europe, Asia and North America, ours is a world-exclusive, while the Chatham Island subspecies is even more unique.
Here in the Waitakere Ranges, west of Auckland, Robert Hoare is looking for another very special New Zealander. Only a century ago, these treetops—rewarewa, taware and kanuka all ablaze with summer bloom—would have swarmed with forest ringlets.
“They should be everywhere,” laments Hoare, a lepidopterist at Landcare Research. It’s a still, sunny day—perfect for butterflies—and their food plants abound. In fact this Cutty Grass Track was named for the thickets of gahnia that forest ringlet caterpillars feed on. “In times past, they would have swarmed about the hilltops, perhaps looking for a mate,” he says. But despite years of surveys, Hoare has never actually seen one here; in fact no one has, not for 30 years.
This absence, this ominous dearth, is only one of many mysteries surrounding our butterflies.
Such as the mystery surrounding their evolution. Clearly, says Hoare, they evolved sometime after the arrival of flowering plants, but we may never know precisely when, because butterflies make very poor fossils. Of the few discovered globally, the oldest is a skipper, some 56 million years old.
“Moths are thought to have originated in the Jurassic,” he says, “certainly over 150 million years ago. There’s still some dispute as to when butterflies originated, but there’s probably a good 80–100 million-year gap between the origin of moths and the origin of butterflies.” Which means butterflies may have appeared right about the time New Zealand loosed its last lifeline with Gondwana, when it split from South America around 85 million years ago.
But lepidopterists can’t say for certain whether our butterflies are descended from ancestral passengers aboard the Aotearoan ark, or from later, wind-blown, immigrants. George Gibbs, a “retired” Wellington entomologist who still works part-time at Victoria University, points out that while some have “been around long enough to have been part of the separation”, others, like the ringlets, feed on grasses, a group that only evolved post-Gondwana. “So I think the butterflies probably came only after that was available in Australia, or some landmass in that direction.”
Whatever their roots, the ravages of time have decimated the butterflies’ family tree. Lepidopterists can only peer at the empty space where branches used to be, and wonder. Gibbs believes the lower boughs represent bottlenecks, choke-holds exerted by ice ages, climatic and geologic upheavals that killed off many species and populations. The upper branches, still sprouting, represent “What’s left…a combination of survival through those bottlenecks.”
“We know about the plants that were lost during the Ice Ages; the assumption is that we would also have lost lots of butterflies too.” Which could explain why New Zealand is home to only two of the five superfamilies of butterflies worldwide. “Even small Pacific islands have all five,” says Patrick. “Isn’t it amazing? We’re probably the only place like that.”
He blames it on New Zealand’s turbulent growing pains—rapid geological uplift, glaciation, marine inundations—which made life too harsh “for five superfamilies to survive, especially when butterflies are essentially tropical animals”.
The most puzzling anomaly is the absence of the skippers—one of the world’s most prolific butterfly groups—which is present even on tiny Pacific atolls. “That’s a family of butterflies that occurs everywhere else in the world,” says Hoare, “and there’s no obvious reason why they should be shouldn’t be here.”
Another noted absence are the white butterflies. There are representatives all over the globe, including Australia, yet—apart from the introduced cabbage white—they still haven’t gained a foothold in New Zealand. And swallowtails, a largely tropical group that include the outrageous birdwing butterflies, have turned up in temperate Australia while our sole record is a Japanese species found in an imported car.
However, our butterfly fauna is just as puzzling for what did establish here, as what didn’t. Lepidopterists are, for instance, confounded by the presence of the little orange and brown coppers, a group that is also found in Europe yet have never made it—or established—in Australia. Why here, and not there? ”The general view is, there’s been a chance, long-distance dispersal event at some time in the very distant past,” says Hoare. “Millions of years ago.
“It does happen,” he says, adding that much the same thing happened with our short-tailed bat. It only takes a single one-in-1000-year storm—like the one that blew pohutukawa seeds to Hawaii—to sprinkle creatures across the Pacific.
It’s tempting to look at a map today and assume the world was always thus, but it’s important to remember that even islands come and go. “The closest relatives to our coppers are two species in the highlands of New Guinea,” says Patrick. That makes it highly likely that coppers island-hopped their way here over now flooded archipelagos. “There’s always a geological link to explain these presences or absences.”
Of course, not all butterflies need stepping stones. Living proof is the monarch, a legendary global wanderer that was first recorded here around 1870. It became established solely because the pioneers were already growing its host, the swan plant, for its fluffy seeds which they used to stuff pillows and mattresses.
Two blues, the long-tailed and the common, have also found their own way here from Australia although Gibbs wonders why more blue species haven’t followed. “We have most of the world’s plant families, but when you get to invertebrates, it’s very selective.”
Most years, the Australian painted lady will hitch a ride over on the Tasman westerlies, and has been found up and down the country, sometimes in large groups. Most arrive bearing the tatters and shreds of their long journey but tellingly, a few of them are in pristine condition. Gibbs takes this as evidence that they bred here during summer but come the cold New Zealand winter, they die out.
Climate change, however, could tip the mercury in their favour, along with a number of other vagrants that have so far failed to establish here.
“The painted lady would come first,” says Gibbs, who suspects that the spectacular blue moon and the lesser wanderer (which has bred here before) might also settle permanently in a warmer New Zealand.
Other potential colonisers are the blue tiger and the meadow argus, but Patrick points out that our winters would need to get a good deal warmer yet, because most arrivals are tropical species, blown from Queensland by virtue of the clockwise spin of the warm nor’-westers that precede a Tasman low.
For New Zealand butterflies however, climate change may not be so beneficial. In one model, the alpine zone, home to so many of our endemic species, is tipped to warm by as much as 6ºC. And according to one study, even 3ºC of warming could destroy 93 per cent of North Island alpine vegetation zones, and 77 per cent in the South Island. That could mean the extinction of between 200 and 300 of our native alpine plants, and the butterflies that depend on them. “Our plants and butterflies evolved together,” says Patrick, “and they’ll disappear together. That will be horrendous.”
This prospect also has George Gibbs worried. “Because it’s the most valuable, intact indigenous area we have. We’ve buggered up everything else, but the alpine zone is still relatively sacrosanct. And obviously, as the climate warms, other things will move up there.” It’s the invasion of weeds that particularly worries him; as pioneering plants such as broom, heather and wilding pines find the uplands more accommodating, they could out-compete the highly-specialised food and host plants our butterflies need.
Yet according to Gibbs, our butterflies are no strangers to turmoil. “They’ve already been through this probably twenty times. Due to ice advances and retreats they’ve been driven up and down mountains, they’ve been amalgamated at certain times and separated at others. So it’s not new for them. [Warming] would extinguish some, sure. But it will bring about others that are not there now. It’s an evolutionary opportunity.”
Indeed, he says, it was that very ferment—millions of years of disturbance, isolation and re-mixing—that shaped the butterfly fauna we have today.
Patrick believes evolution took greater advantage of that upheaval than we realise, creating three times the number of species currently recognised.
For years, he and his son Hamish have been looking very closely at copper butterflies around New Zealand. When they began comparing specimens from various regions, and from the other side of the globe, they noticed some differences; perhaps in the markings on the wings, or the colouration. Out in the field, they noticed subtly different flight patterns, food preferences, seasonal emergences. “It’s really quite exciting,” says Patrick. “Even from a superficial point of view, there are some very significant differences.
“Modern techniques are now saying that we have a lot of unnamed copper butterflies.” He maintains there are 11 more mountain ringlets, too. Currently, just one is recognised. “And one new tussock butterfly that we didn’t previously know we had. It’s debatable how many extras we’ve got, but we believe we have about 75 species, rather than the 23 the books will tell you about.”
Patrick maintains that, separated by advancing ice sheets, heaving crust or shifting coastlines, once-homologous populations of coppers began, over the course of eons, to diverge. “It’s not a huge surprise. The alpine plant people will tell you the same thing. A lot of recent diversity in New Zealand has been associated with mountain-building.”
But one man’s species is another man’s variant, and there is not yet consensus on the matter. For instance, Robert Hoare is yet to be convinced of the exclusivity of some of the “new” coppers. “It very much depends on what you call a species. My own view is that they’re not as different as your traditional species ought to be, and it’s a bit premature to consider them as such.”
Entomologist Christopher Rickards has studied coppers both here and overseas, and says that while the variation in our coppers is what makes New Zealand forms interesting, it’s not uncommon within the genus internationally. “I’ve studied coppers in Europe, Turkey, India, China and North America,” he says. “The same variations occur in all these places; the higher the latitude or altitude, the more dark scales the form exhibits.” He also harbours similar doubts about Patrick’s “extra” mountain ringlets, believing the number to be closer to two or three additional species.
But Patrick is unfazed. “There are always the doubters, and that’s what keeps science going, keeps it honest. You have to realise that the whole species concept is artificial. Nature doesn’t care about species. It’s just a continuum, and we recognise there is huge diversity out there. We’re pretty confident with what we’ve found and that our native copper fauna will only grow.”
George Gibbs is following the debate with interest and has some experience in the matter. He went through a similar exercise in 1980 when he resurrected Rauparaha’s copper, a species originally described in 1898 but which had been subsequently lumped back in with the common copper. Nevertheless, Gibbs’ tally stopped at four. The others, he says, “are slightly different, sure, but at that stage I decided they weren’t justified as being separate species”. He happily accepts that the coppers (and the ringlets) have “radiated”, or diverged from a single ancestral lineage. “There are some very obvious radiations, which may have happened way back in the Miocene, but on top of that, there’s a bunch of recent radiations associated with modern geography, which possibly happened only a million or fewer years ago. It will need modern techniques to unravel.”
But while our butterflies may have taken the ice ages in their stride, perhaps even capitalised on them, the winds of environmental change could be blowing faster than they can fly against.
Every Christmas, Gibbs goes rummaging among the grasses and sedges around Wellington’s Eastbourne with a red umbrella in hand. Placing it under a Gahnia sedge plant, he gives the leaves a sharp tap. Years ago, a handful of green caterpillars—next year’s ringlets—would have dropped onto the contrasting background. Most days now, the umbrella is empty.
“The most I ever got,” recalls Gibbs, “were 30 larvae in a day’s work. Last year, I got five. I’m going to be around long enough to see the forest ringlet go extinct in this region.”
The ringlet, arguably our most beautiful native butterfly, has all but vanished from lowland tracts around the country—at least below an elevation of 400 m. And there, many believe, is the smoking gun.
“It’s noticeable,” says Hoare, “that these butterflies still seem to be present, and occasionally, reasonably common, at 600 m.” That just happens to coincide with the altitudinal limit of German and common wasps. It seems that these wasps are killing our forest ringlets, which would explain all those fruitless surveys in the Waitakeres where wasps are rampant.
If climate change means that those wasps move higher, forest ringlets will just run out of available habitat. And there are other concerns; many small parasitoid wasps have been imported into New Zealand as bio-controls against other introduced insect pests. In times past, few tests were done to check whether they might simply host-switch to native insects. And while import standards are today much more rigorous, Patrick worries that a single biosecurity breach could spell disaster for native butterflies.
“It will happen silently, that’s the worst of it,” says Hoare. “One summer will come along, and the population of red admiral butterflies will have crashed. Then it will be too late; the parasitoid will have gotten a hold, and it will be impossible to raise the money to be able to control it.”
Whether Patrick’s coppers are new species or discrete geographic races, they throw up a conservation dilemma; which populations will we try to save? He points to one community of boulder coppers known only from a single carpark on the Otago coast, that could number in the tens. “The boulder copper is found from Taupo to Foveaux Strait. We might conclude that it doesn’t matter if we lose that one, if there are plenty of others in Central Otago.
“But I don’t care whether it’s a form, species or family, the fact is it’s different. Nature is telling us something about that time and place, and that entity. Then it becomes important.”
Patrick was first captured by butterflies as a boy, when he witnessed the magic of metamorphosis. Even now, when he knows how the trick is done, the enchantment endures. In fact, it may be radiating, just like his coppers. His neighbours have planted Muehlenbeckia, the coppers’ favourite food plant, and Mayfair Grove will be all the more attractive for them.