Introducing the inaugural New Zealand Geographic & Heritage Expeditions reader voyage: Hauraki Gulf and Bay of Islands
The mantis shrimp subdues its prey by punching it with a blow that’s strong enough to crack a glass aquarium and generates enough heat to boil water. So when do baby mantis shrimp develop this super-smash prowess? To find out, Duke University researcher Jacob Harrison headed to Hawai‘i with a high-speed camera in search of Gonodactylaceus falcatus larvae—one of the world’s 450 species of mantis shrimp. First, he had to catch a four-millimetre-long larva. “It can be incredibly challenging to sift through a bucket teeming with larval crabs, shrimp, fish and worms to find the mantis shrimp,” says Harrison. Then he had to position the larva in front of his high-speed camera—a task that ended up taking a year to perfect (and involved supergluing the larva to a toothpick). But the effort was worth it. The high-speed footage revealed the mantis-shrimp punch in action: the limb bending back like a spring, before a tiny latch is released that flings the appendage forward with impressive acceleration and speed—around 38 centimetres per second. While the larva was slower than full-grown adults, the jabs were still five to ten times faster than the swimming speed of similar-sized organisms, and 150 times speedier than their prey. After raising some larvae from eggs, Harrison observed that they first began to hunt with their forelimbs between the ages of 9 and 15 days. Although young mantis shrimp go through six to seven transformations from hatching to fully grown, Harrison’s footage showed that the spring-and-latch mechanism is the same in young and old. And while the larva’s punch may be scaled down, the transparent exoskeleton of larvae revealed remarkable detail previously unseen: the tiny muscles contracting as the mantis shrimp wound up for another devastating blow.
Kea are the mischief-makers of the mountains, but a genome study shows they are not tied to alpine areas. As rising temperatures shrink their habitat, they could return to lowlands—if they can find suitable places to live. Fossils suggest that kea once occupied low-lying areas throughout the South Island and even in the North Island. In fact, there’s nothing “to stop kea from living at lower altitudes”, says University of Otago evolutionary geneticist Michael Knapp. The research scoured the genomes of kea and its sister species kākā, which is adapted to life in the forest, for any genes known to be involved in adaptation to life in the mountains. The commonly held theory was that kea and kākā went their separate ways about two or three million years ago, when the Southern Alps were still rising and opening up new alpine habitats. But Knapp says an ice age was redrawing the landscape at the same time, reducing forests in its wake. “For the ancestors of kea and kākā, their forest habitat shrank, and that made it more likely that some populations ventured into new habitats. That’s what distinguishes them—the kea is the species that went into the open.” The kea’s later retreat to alpine altitudes may have had more to do with avoiding people—including a bounty-hunting scheme that lasted more than a century, from 1867 to 1970, and killed some 150,000 birds. Thankfully, the genome doesn’t show a genetic bottleneck, which suggests the bounty-hunting period was short enough to avoid denting the birds’ genetic diversity, says Knapp. But the study has found a significant difference between the two parrot species. Kākā respond quickly to improved living conditions. When forest cover expanded in the past, so did kākā populations. In contrast, the kea population remained relatively constant, regardless of habitat changes. “Is the kea better at buffering bad habitats, or not so good at responding to good conditions?” asks Knapp. Both species may struggle to adapt to a warming world, says University of Otago PhD candidate Denise Martini. “If native forests begin to suffer from warmer conditions, it is very likely that kākā will suffer, too. Kea might be able to adapt to new conditions, but that depends on whether new conditions are available in the first place. My recommendation for conservation programmes would be to focus on restoring and preserving as much of the existing habitat of both species as possible.”
In the summer of 2015, in a remote valley of Fiordland National Park, two scientists discover fossil poo fragments underneath a limestone overhang. Analysis suggests the fragments are from moa and are thousands of years old, so a team returns—three years later—to excavate. What they find is a rich deposit of moa poo—called coprolites—that accumulated over a period of two millennia, probably between 6800 and 4600 years ago. But what use is old poo? Scientists can carefully examine the pollen, seeds, DNA and plant microfossils in coprolites to determine what kind of food fuelled the nine moa species that roamed the country. The team determined that these nuggets of dietary information were from little bush moa (Anomalopteryx didiformis), a mid-sized species between 50 and 90 centimetres tall and weighing 26 to 64 kilograms that inhabited lowland forests. This made it an exciting find. “Until now, only five little bush moa coprolites have previously been identified, all from Central Otago,” says lead researcher Jamie Wood from Manaaki Whenua–Landcare Research. The poo contained very few seeds, suggesting that little bush moa were not important seed dispersers. But the fossils were rich in ground-fern spores and fronds, suggesting that fern foliage played an important role in this species’ diet, and that the moa spread the plants around. Because the coprolites were deposited over a period of 2000 years, the researchers were able to trace how the plant matter contained within changed over time. This revealed a shift in the prevailing vegetation from conifers such as miro, mataī and tōtara to the silver beech trees that dominate today.
Over the past year, at least 46 countries have recorded outbreaks of the bird flu strain H5N8 among both poultry and wild waterfowl. As a result, millions of birds across Europe, Asia and Africa have been culled. In December 2020, the first H5N8 infections in humans were recorded, with seven Russian poultry workers testing positive for the virus. Although the people did not display any symptoms, the chickens did not fare so well. More than 100,000 from the 900,000-strong flock died. Bird flu comes in a variety of different subtypes, with H5 and H7 particularly concerning due to their potential to affect humans and other animals (there was an outbreak of H5N1 bird flu in captive tigers in 2004). Although rare in humans, bird flu can be deadly. Since 2003, there have been 862 cases of H5N1 bird flu worldwide. More than half of the people who caught H5N1 died. Fortunately, human-to-human transmission has occurred in only a handful of cases. Most infections arise from contact with sick birds. But the ease with which influenza viruses can mutate means that the threat of a bird-flu pandemic looms large. In June, China reported the first confirmed human infection of H10N3 bird flu, a rare strain. Scientists are calling for increased surveillance of poultry farms and wild birds—to find strains with pandemic potential, before they find us.
The emergence of a new coronavirus is not a question of if, but when and where—and a new study has answered the latter by mapping global regions most likely to produce the next outbreak. The research used horseshoe bats as a model, because they carry several coronaviruses from the same group that caused COVID-19, SARS, and a pig disease known as SADS. The study then connected the dots between several details: where the bats lived, forest fragmentation caused by expanding farmland, human population growth, and increasing numbers of livestock. Where all these things overlap, they “form a nexus where you might have really high risk”, says David Hayman, a Massey University infectious disease ecologist who was part of the international research team. The map—a swathe of horseshoe bat habitat from Spain in the west to the coast of Australia in the east—identifies China as a global hotspot, as well as Bhutan, east Nepal, northern Bangladesh and Thailand, all places where the next spillover event is most likely to transmit a virus from animals to people. In host animals, such viruses usually cause no harm; in other species, such as humans, the viruses can lead to severe and highly contagious disease. We know that if people encroach on wildlife, the risk of spillover increases, says Hayman. Our best chance of preventing such animal-human transmissions from growing into major outbreaks is to increase disease surveillance in high-risk areas. Heightened surveillance could also help contain outbreaks of existing spillovers, such as Ebola, which now re-emerges almost annually. But with a viral universe that likely includes millions of different strains, we need to think beyond pandemic preparedness. “If we really want to reduce the risk, then we need to look at the bigger things—what is causing forest fragmentation, and should we be putting another intensive farm with livestock in this area,” says Hayman, “because the same things that increase the risk of disease emergence also contribute to biodiversity loss and climate change.”
The world has a big COVID-19 problem. But just how big? Each infected person carries between one billion and one hundred billion virus particles at the peak of infection. This equates to no more than 0.1 milligrams of virus per infected person—about the same as a single poppy seed. Multiplying by the number of infected people around the world, researchers estimate that our COVID-19 problem can be chalked up to between 0.1 kilograms and 10 kilograms of virus.
Atop the great snow-laden hulk of Ruapehu, the bluish crater lake acts as a barometer for volcanic unrest. Colour changes, rising temperatures and gas emissions measured at this active vent could all point to the possibility of eruption. Now, scientists have another symptom to keep an eye on: sustained, subtle increases in the surface temperature of the whole mountain. Three United States researchers used infrared satellite data to examine five volcanoes around the world: Ruapehu in New Zealand, Ontake in Japan, Calbuco in Chile, Redoubt in Alaska, and Pico do Fogo in Cape Verde. Across 16 years of records, they found that surface temperature increases of up to 1°C preceded eruptive episodes. This slight warming may be a symptom of hydrothermal activity and underground gasses diffusing across large areas, resulting in a change in temperature on the mountains’ flanks that can be detected from space. Sometimes, the warmer temperature lasted for years. The precise warning signs of an imminent eruption remain elusive—crater lakes aren’t crystal balls—but this new method of keeping tabs on volcanic unrest may help anticipate eruptive phases.
In January 2020, Jérôme Mallefet went looking for glowing sharks on the Chatham Rise, off the east coast of the South Island. As researchers on the NIWA ship Tangaroa hauled up trawl nets full of hoki for their annual fisheries survey, Mallefet kept his eyes peeled for bycatch. He and colleagues collected more than 600 deep-sea sharks, representing three species, and transferred 24 into tanks in the wet lab. As the ship pitched and rolled, they photographed the sharks in the dark. They discovered that all three shark species had the ability to glow: two small lanternsharks, and the kitefin shark, Dalatias licha, which reaches up to 1.8 metres in length. That makes the kitefin shark the largest light-producing creature—with a spine—that has ever been found. Mallefet, an expert in bioluminescence from the Catholic University of Louvain in Belgium, says other studies suggest that around ten per cent of the Earth’s approximately 540 shark species can glow. So why do they do it? Partly to recognise each other in their deepwater home, as each species lights up in a particular way. It may help males and females align for reproduction. And glowing can also make the sharks invisible. “These guys are living in the twilight zone, where there is a bluish faint light coming from the surface,” says Mallefet. Seen from beneath, the animals’ bodies appear as silhouettes against the light. But when the kitefin shark illuminates its entire belly with a blue glow, it blends into the light from above. “Suddenly you disappear—that’s how counter-illumination works.” Their dorsal fin also glows—but why remains a mystery. Other recent studies have shown that as many as three-quarters of marine animals in the water column have the ability to make their own light. “Bioluminescence is so widespread, it must have a really critical role for the survival of these organisms down there,” says Mallefet. “The way they communicate, the way they reproduce—bioluminescence plays a role in it, and we are only just discovering that now. “It must be glowing Christmas trees everywhere down there, that’s for sure.”
The phases of the moon affect how fast baby fish grow, a new study has found. Ecologist Jeffrey Shima from Victoria University of Wellington and colleagues found sixbar wrasse larvae grew fastest during the last quarter of the moon—when the first half of the night is dark, and the second part is bright. That’s because when reef fish release their larvae, these float out into the open ocean to feed. There, they meet the mass migration that takes place every night as millions of fish and plankton rise from the deep to feed, then sink before dawn to hide in the dark. Baby sixbar wrasse feed on plankton, which rise more quickly than their predators. But when predators such as lanternfish arrive at the surface, they use their bioluminescent tummies to camouflage themselves against the moon’s light and sneak up on the wrasse. Shima’s hypothesis is that when the moon is full, it’s too bright for plankton to feel safe and for predators to properly conceal themselves, so neither rise all the way to the surface. That leaves the wrasse hungry, but safe. On dark nights, there’s plenty of food—and plenty of lanternfish. But during the last quarter, when the moon rises at midnight, the plankton have already reached the surface, and by the time the predators join them, it’s too bright for them to hunt successfully. The wrasse larvae feed freely and grow more quickly. “This has really big implications for explaining why we see a lot of variation in the survival rates of baby fishes,” says Shima. “If you have months that are more cloudy than average, that might have serious consequences.” Artificial lights from cities may also disrupt these natural cycles.
Could taking tiny, regular doses of psychedelic drugs enhance your mental health? Not any more than a sugar pill, according to the largest placebo-controlled study on “microdosing” to date. Microdosing involves taking substances such as LSD or psilocybin (the hallucinogenic compound in magic mushrooms) a couple of times a week, at around 10 per cent of a typical recreational dose. It has recently surged in popularity, as the dose is too small to cause hallucinations, but is purported to improve mood, creativity and psychological wellbeing. One hundred and ninety-one people volunteered for the study, administered by researchers in the United Kingdom. Over four weeks, the participants either took drugs or a placebo, without knowing which they were ingesting. After four weeks, those taking psychedelics reported significantly improved wellbeing and life satisfaction. So did the people taking inactive capsules. There were no significant differences between the two groups—both experienced the same positive effects. The researchers suggest the benefits of microdosing arise not from drugs, but from the power of our own expectations.
The ocean is awash with noise. The clicking of shrimp snapping their claws, the crunching of reef fish grazing, the rumble of a vessel passing overhead—sound travels fast underwater, and in all directions. For animals that rely on sound for communication, such as whales, a cluttered soundscape can be stressful, causing them to change their behaviour. To hear what whales hear—and map where they go—researchers deployed four acoustic recorders in the waters around central New Zealand, collecting soundwaves at various frequencies. The recorders detected the ethereal calls of four whale species: pygmy blue, Antarctic blue, humpback and Antarctic minke whales. Pygmy blue whales were abundant in the South Taranaki Bight, with some visiting Kaikōura in autumn. The other species passed by New Zealand on their annual migration between the tropics and Antarctica. The sound recorders also captured the whooshing ambient background of rain, tides, waves and wind, even earthquakes. Human-generated noises from seismic surveying and ships were also common, and at times overlapped with the whales’ calls. The researchers say this audio information helps identify places in the ocean where human noise might be limited for the whales’ benefit. Whales aren’t the only animals facing hearing problems. Growing up in acidic waters can cause hearing damage in snapper, according to a different study by New Zealand and Australian researchers. Young snapper raised in conditions with elevated carbon dioxide levels were significantly less sensitive to low-frequency sounds. This diminished ability was attributed to changes in the structure of their ear bones and brain chemistry resulting from increased acidity. Hearing is critical for many fish species, playing an important role across their lives: from larval fish deciding where to settle, to individuals synchronising for spawning, to making contact with others.
In issue #166, New Zealand Geographic covered a research project to track tohorā/southern right whales and learn where they swim over the summer. The results are in. As this issue went to print, only one whale’s transmitter was still functioning, that of Wiremu, the whale named after New Zealand Geographic journalist Bill Morris. Wiremu/Bill is the light blue line travelling along the coast of Antarctica.
The first kiwi sent from New Zealand to Europe arrived in England around 1812. Its insides had been removed, its skin and feathers preserved, and its little body flattened into an un-lifelike shape. It was a tokoeka/South Island brown kiwi, and it became the holotype of the species, the individual animal associated with the scientific name given to it in 1813, Apteryx australis. Where exactly the specimen came from was a mystery. Naturalists assumed it was collected in Fiordland’s Dusky Sound. Now, cutting-edge ancient-DNA techniques have revealed its true origins—which means new scientific names will need to be found for three other groups of tokoeka. In 2017, Canterbury Museum curators Paul Scofield and Vanesa De Pietri visited the holotype at the World Museum Liverpool, where they were given a sample of the bird’s skin the size of a fingernail clipping. Back in New Zealand, Scofield and colleagues mapped the kiwi’s mitochondrial and nuclear DNA, then compared the sequences with the genomes of living kiwi. The results showed the specimen was genetically distinct from the Fiordland tokoeka, meaning it wasn’t from Fiordland at all. Instead, it was from the world’s southernmost kiwi population, on Rakiura/Stewart Island. Researchers checked their finding against the historical record, and it stacked up. When the kiwi specimen was collected in 1811, Fiordland seal populations had been cleaned out, and the few sealing gangs remaining had moved to the northern side of Foveaux Strait. Using shipping data from early newspapers, Scofield’s team established that just one vessel, the Sydney Cove, was sealing near South Cape on Rakiura at the time. One of those sealers probably caught the kiwi. When the sealing crew landed in Sydney, they sold seal and kiwi skins to Andrew Barclay, the captain of a convict ship and former privateer (during the Napoleonic Wars, he obtained a licence from the British monarchy to board and sink French ships). Barclay sailed to China, where the seal skins would be made into leather for top hats, then continued to London. The kiwi specimen ended up in the private collection of George Shaw, keeper of zoology at the British Museum, who bestowed its scientific name. Now that we know the kiwi came from Rakiura, according to the rules of taxonomy, the Rakiura population must now take the Apteryx australis name—an appropriate one, as australis means southern. Research continues into whether the genetically distinct populations of tokoeka on Rakiura and in southern Fiordland, northern Fiordland and Haast are separate species or subspecies. Once that’s been figured out, the three other groups will need new scientific names—an opportunity to use Māori terms for these taonga.
The first cases of COVID-19 arrived in New Zealand on February 26, 2020—or so we thought. Now, testing has revealed the virus began to spread slightly earlier. A traveller from Italy arrived on February 23, then became ill with what seemed like the flu. So did six members of their household. They didn’t qualify for COVID-19 testing at the time, but followed advice to isolate and recovered. Six months later, one member of the group came down with a cold, had a nasal swab, and returned a weak positive result for COVID-19. Further testing revealed the man already had antibodies for the virus, so researchers concluded that the viral genetic material detected was residue from a past infection (and that the man probably wasn’t contagious). For researchers, it reveals that the virus can still be detected in the body up to 201 days after an initial infection. This is now the first known case—and cluster—in New Zealand.
To find out how much New Zealanders are drinking and smoking, a group of researchers turned to sewage. Across one week in March 2018, researchers collected samples from seven treatment plants in three regions: Auckland, the Bay of Plenty and Canterbury. They measured the levels of alcohol and nicotine metabolites, the molecules excreted after your body breaks down the drinks and smokes. Results were adjusted for population to determine how much was consumed per person. From a pile of excrement came a treasure trove of scientific insights. Across all regions, and especially in urban areas, people drank more alcohol on the weekends, whereas smoking remained consistent throughout the week. Cantabrians and Bay of Plenty residents consumed more nicotine and drank more than Aucklanders. Nicotine consumption was higher in economically deprived neighbourhoods. Nicotine and alcohol aren’t the only substances sought by scientists in sewage. Government scientists also monitor wastewater for traces of COVID-19—a possible early-warning system for undetected community transmission—and for drugs, to help authorities map drug use.
A study has found that dogs exhibit jealous behaviour and can imagine their owners’ ‘infidelity’ even when they can’t see it. Researchers at the University of Auckland recruited dog owners and placed a chest-high barrier between the humans and their furry friends. The owners had to wear noise-cancelling headphones and goggles to avoid giving any unintentional cues to their pets. The barrier was opened for long enough that the dogs could see there was either a social rival—a realistic-looking fake dog—or a fur-covered cylinder near their owner. The dogs pulled much harder on their leads when their owners were patting the fake dog compared with the control box—and significantly, they did this even when the barrier was closed and they could no longer see the fake dog, says study lead Amalia Bastos, a doctoral candidate at Auckland. “This is the first time that anyone has shown that dogs can actually imagine social interactions they can’t see—they’re sort of playing a little movie in their head.” No-one had ever tested whether dogs could do this before, Bastos says. “I think people tend to underestimate what dogs are capable of in terms of their social intelligence.” Other studies have been divided over what dogs’ jealous behaviour actually looks like, and therefore whether there really is any evidence for it—but these researchers took a lead from the science on jealousy in infant humans. Human babies and toddlers consistently tend to try to get closer to their mother when jealous of her attention going elsewhere—and the new study shows that dogs exhibit a similar response, says Bastos. “We’ve definitely shown jealous behaviour in dogs. But whether that means they’re subjectively experiencing jealousy in the way we do is a much harder question to answer.” The results give scientific weight to what many dog-owners have long suspected — surveys have shown that people believe their pets do get jealous. But Bastos hopes the findings may also help change attitudes towards animals and how we treat them. “They might be actually more similar to us than we give them credit for.”
Small-scale fisheries land half of the world’s catch—but not much is known about the 40 million people involved in them, or how many fish they’re pulling out of the sea. This means governments make policies based on inaccurate estimates of catch and consumption, which can lead to unsustainable fisheries. A group of international researchers, including Shaun Wilkinson from Victoria University in Wellington, have developed a free smartphone app using open-source software that fishers, government managers, and researchers can use to accurately track catches in real time. They tested the app in Timor-Leste between 2016 and 2018, co-designing aspects of it with fishers and local fisheries managers, and in 2019 the Timorese government adopted the app as its national fisheries monitoring system. Called PeskAAS—the name references the word for fisheries in Tetum, the national language of Timor-Leste—the app can be used to collect detailed data on species caught, fishing methods used, habitat fished in, time spent fishing, and the price of the fish. Since 2016, nearly 60,000 fishing trips in Timor-Leste have been tracked using the technology, with catches recorded for nearly 30,000 of them, and the data has been incorporated into new fisheries laws. The researchers hope the technology will be widely adopted by other countries—though they acknowledge that it is designed for boat-based fisheries, compounding the invisibility of women fishers, who often collect seafood near the shore and on foot.
Human antidepressants flow into waterways after passing through the body, where they affect the behaviour of fish. Australian researchers created tanks of water polluted with one of the world’s most commonly prescribed antidepressants, fluoxetine (also known as Prozac), at concentrations that have already been detected in waterways around the world. Over two years, the scientists raised generations of guppies in the contaminated water. They found that the antidepressant made guppies act more similarly—even low concentrations resulted in the fishes’ behaviour becoming more conformist. Variety is crucial to survival—it helps animals adapt to change.
Plants are our best technology for soaking up carbon dioxide from the atmosphere, but a new study shows the world’s forests and grasslands could flip over to become a source rather than a sink of CO2. Currently, the world’s green spaces absorb about a third of the emissions we produce by burning fossil fuels. But at the current rate of warming, plants’ ability to inhale more carbon dioxide than they exhale will slow down, then reverse, shrinking the carbon sink to almost half its size by as early as 2040. A study published in Science Advances in January looked at the link between temperature and photosynthesis (the process plants use to turn carbon dioxide and the sun’s energy into oxygen and sugars for their growth) and respiration (which releases carbon dioxide). Researchers analysed datasets from a global network of meteorological sensors known as FLUXNET, which tracks a suite of atmospheric variables, including carbon fluxes above different biomes. The study found that photosynthesis has a much lower ideal temperature, between 18°C and 28°C depending on the type of plant, than respiration, which means that as global temperatures continue to climb, photosynthesis will slow while respiration keeps rising. Some ecosystems in warmer parts of the world, including the Amazon, already reach this threshold during certain times of the year. Earlier studies on specific trees suggested that some would grow faster at higher atmospheric levels of carbon dioxide, but this wider study found no such effect. Nor did it find any evidence that plants adjust to perform higher rates of photosynthesis at higher temperatures. The results are a wake-up call, says one of the study’s authors, University of Waikato soil scientist Louis Schipper. “The biosphere has been harvesting our emitted CO2 and we assumed that would carry on. But this data shows the size of this terrestrial carbon sink will go down. It blows me away how near this is.” Add to this the increasing risk of wildfire and drought, and stressed plants’ lessened resilience to pathogens, and it’s clear, says Schipper, that we can’t count on “this idea of just planting trees”.
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