Genetic reanalysis in the Amazon has revealed that the electric eel is, in fact, three different species, including one—Electrophorus voltai—that can deliver an 860-volt shock. (That won’t kill a healthy person, says ichthyologist and lead author Carlos David de Santana, from the Smithsonian National Museum of Natural History.) The new species is now officially the strongest bioelectricity generator known, making the previous record of 650 volts a mild tingle.
Embryonic turtles can choose what they’ll be when they grow up: male or female. In particular turtle species, the temperature of the egg appears to determine the sex of the hatchling. Research published in August in Current Biology found that embryos are able to move around within the egg to find different temperatures. Wei-Guo Du and colleagues at the Chinese Academy of Sciences incubated turtle eggs at a range of temperatures, finding that an embryo could experience a gradient of up to 4.7°C within its egg. (A temperature change larger than 2°C can alter the sex ratio of many turtle species.) In half the eggs, researchers applied a chemical that blocked the embryos’ temperature sensors. When the eggs hatched, the embryos that weren’t able to sense temperature were either almost all males or almost all females. But the temperature-sensing embryos developed about half and half males and females. “The most exciting thing is that a tiny embryo can influence its own sex by moving within the egg,” says Du. This indicates that turtles may have the ability to shield themselves against extreme thermal conditions. Du warns that this may not be enough to protect them from rapid climate change, which is predicted to create female-biased populations. “However, the discovery of this surprising level of control in such a tiny organism suggests that in at least some cases, evolution has conferred an ability to deal with such challenges.”
A sea sponge may one day save millions of lives, according to a study published in Scientific Reports in October. Tuberculosis kills 1.8 million people each year, more than any other disease, and current vaccines are struggling to contain it. That’s because Mycobacterium tuberculosis, the organism that causes TB in humans, is quick to mutate, meaning it can soon evolve drug resistance. The quest for a better vaccine has led scientists beneath the waves, looking for bioactive molecules in sponges: compounds that might one day comprise the basis of new vaccines. Over three years, the Centenary Institute and the University of Sydney analysed around 1500 sponges, and discovered that a species of Tedania, a genus found around Australia and New Zealand, possesses potent powers against M. tuberculosis. The active component, Bengamide B, was able to halt drug-resistant TB strains, and did not harm human cells. “Bengamide B shows significant potential as a new class of compound for the treatment of tuberculosis,” said the study’s lead author, Diana Quan, “and also importantly, for the treatment of drug-resistant TB.”
Normally, more than 200 sightings of great white sharks are recorded every year in False Bay, near Cape Town, South Africa. This year, that number is zero. Receivers that are supposed to ‘ping’ when a tagged shark passes by remain silent, while whale carcasses usually found in the bay are free of shark bite marks. False Bay is a renowned great white hotspot, and shark scientists are puzzled by the predators’ absence. It’s possible that orcas are the culprits—they’re known to attack great whites, and have a particular taste for their livers. Indeed, sightings of great whites decreased after two orcas visited False Bay in 2015. Alleged victims of orca predation have washed up along the South African coast, their livers removed with surgical precision—the orca’s calling card. This is also consistent with observations from Australia and California, where orcas on the prowl have led to a mass exodus of great whites. But there’s another suspect in this case: humans. It’s possible that changing prey distribution, pollution or overfishing could also be responsible for the missing sharks.
Warming seas will make life much harder for pāua, a NIWA study has found. Scientists raised young pāua in seawater of various temperatures and pH levels, then monitored their growth. “Essentially, seawater of the future will be warmer, with lower pH levels,” said Vonda Cummings, pictured, who led the study. “We found that the outer layer of pāua shells gets etched by seawater with lower pH, especially if the water was warmer.” The pāua were sensitive to temperature variations as small as 2ºC, “and that will affect the thickness of pāua shells, which could mean they are not as resistant to waves and predators”.
Giant carnivorous land snails don’t ask for much: moist leaf litter to burrow into, earthworms to suck up like spaghetti. But if the lower layer of the forest is nibbled away, if sunlight reaches the soil, and if one month of drought follows another, molluscs relying on damp homes struggle to survive.
Zip, pip, chuck, goes the call of Aotearoa’s smallest bird. It may turn out to be one of the earliest forms of language.
Can humans also regenerate damaged limbs?
Some people at the Department of Conservation did not want us to tell you about the Mokohinau stag beetle featured in this issue of the magazine. This is why we’ve decided to do so. There have never been many stag beetles on the Mokohinau islands. A lone species has been having a rough time out there, clinging on, somehow managing to survive. Researchers have never seen more than 10 of them at once. The beetle is considered so critically endangered that, in the words of Auckland Zoo reptile and invertebrate expert Don McFarlane, “there needs to be a new version of the word critical”. Their plight is beyond critical. McFarlane’s enthusiasm for the beetle is infectious. I first heard him talk about it when I was working with him on a completely different story. The way he describes the beetle, it sounds like a living marvel. It’s the crazy, far-off relative of the Geodorcus stag beetle family, the wild loner living on a rock in the sea. I wanted to see its knobbly jaws for myself. Then I wanted everyone to see its knobbly jaws. Beetles are the underground workers of our ecosystem, part of the extremely complicated clockwork that keeps our wild habitats ticking along nicely. We don’t know what will happen as more and more of these species disappear. We have a whole taxon of Geodorcus beetles that dispersed across the country and became slightly different from each other, depending on the environments they found themselves in. We don’t know a whole lot about some of them, either. McFarlane is still reeling from the results of the survey. They’ll need to go and take another look, but fellow searcher, ecologist Greg Sherley, is also feeling pessimistic. He’s looked for these beetles before, and found them straight away, at the same time of day and year as this survey took place. Beetles take a long time to become beetles: they spend most of their lifespan as larvae, buried, usually in rotting wood. We don’t know if any larvae still lie in wait on the Mokohinaus. “We’ll never know for sure unless we keep looking, and keep looking long after I’m dead,” says McFarlane. Sherley is worried that, even if beetles remain, there may too few to save the species. Those at DOC who opposed this story did so because they believe publicising the beetle increases the poaching risk to it. But it’s a bit late for poaching. The risk of theft seems like a good reason to start measures to protect the beetle. Though a plan for saving it has long existed, it is only just beginning to be put into action, and in large part due to volunteer effort. Ian Stringer and Greg Sherley, both retired from DOC, paid their passage on the survey and donated their time. We believe it’s important to tell you about this beetle, that it’s special, and that it’s possible for you to advocate for its preservation. You deserve to know that there was a beetle we could have saved—and that we might still save, if we’re lucky. You deserve to know that the cost of conservation budget cuts is paid in beetles. That species are blinking out around us, unknown, unpublicised. You need to know because you vote for these things. In 2009, DOC’s budget was cut by $54 million over four years—particularly bad news for those DOC staff who are enthusiastic about beetles and advocate for their protection. If beetles are on the front line of the global extinction crisis, then entomologists are on the front line of budget cuts. Halting plans to save invertebrates results in the least public outcry, especially if no one knows they’re there in the first place. Beetles need help, and not only from technical experts figuring out how to get them to mate in captivity. They need your help, too.
Some species just like it cooler. Others have withdrawn little by little to higher altitudes, making new homes where it’s too cold for their enemies to follow. But warmer seasons allow predators and diseases to gain ground and advance above the bushline—meaning that the alpine zone is no longer the refuge it once was.
The Mokohinau stag beetle is one of the world’s most endangered species, occupying less than an acre of scrub on a rocky tower in the middle of the ocean. Its habitat is so precarious that Auckland Zoo and DOC are hoping to safeguard a population of beetles on the mainland as a form of insurance—that is, if there are any left.
Albatrosses are good omens for sailors, but are not having too much luck themselves. The population of female wandering albatrosses that nests on Antipodes Island has plummeted by two-thirds in the past 14 years. This rapid decline has alarmed researchers Kath Walker and Graeme Elliott, who have been studying the species for two decades. There appear to be a number of causes, but the primary one is changing oceanic conditions that force the birds to forage in more northerly waters where the risk of being caught by commercial longliners is higher. Some years have seen female mortality rates as high as 20 per cent. “We think about polar bears with despair, but it’s a rather similar sort of situation here,” said Walker in an interview with RNZ. [caption id="attachment_344954" align="alignnone" width="1066"] Numbers of Antipodean albatrosses are declining on the Antipodes.[/caption] Antipodean albatrosses forage for squid, which is also used as bait by the longliners. While many fishers have a suite of techniques and technology to avoid bycatch, those that don’t risk birds taking the hooks and drowning with the sinking line. As Antipodean albatrosses raise only one chick, and both adults provide food during the first year, the loss of a single adult often means the death of its chick too. Antipodean albatrosses range widely—far beyond New Zealand’s exclusive economic zone, into the stateless realm of the high seas and as far east as Chile’s continental shelf. Regional fisheries management organisations regulate fishers out there in a similar way to those in New Zealand waters, but the level of compliance and reporting of bycatch is debatable. Without better data on where the birds are foraging—and dying—researchers are at a loss to determine the threats to the population. There are some 3000 registered longliners in the Pacific, and it’s uncertain which vessels or jurisdictions they interact with. To complicate matters, female Antipodean albatrosses forage further to the north, in more dangerous waters, and are disappearing at a greater rate than the males, leading to a severely skewed sex ratio. The Department of Conservation and the Ministry of Primary Industries deployed about 75 satellite-transmitting devices on Antipodean albatrosses this year, and in association with the Southern Seabirds Solutions Trust, intend to deploy the same number again next season. The tags track the birds’ locations as they forage, and researchers can overlay this data with the position of fishing vessels operating in the area to determine the risk of contact. If left unchecked, the Antipodes Island wandering albatross could be the first albatross species in the world to become functionally extinct.
Manta rays have unique patterns of spots on their bellies, allowing individuals to be identified. University of Queensland researchers have created a database of more than 1300 manta rays, supported by a citizen-science project. Scientists are able to keep track of the movements and health of reef manta rays (Mobula alfredi) via photographs and videos submitted by members of the public. More than 7000 sightings have been recorded, showing that manta rays can travel up to 1000 kilometres at a time. The data will inform conservation projects and reef management.
It’s been alone for two million years, during which time it lost the ability to fly, and its habitat has shrunk to just a few hundred metres of stream with a view of Dunedin Airport—but the Maungatua stonefly is finally enjoying a moment in the spotlight. Its discovery was an accident: Jon Waters, a professor of zoology at the University of Otago, was out in the Maungatua Range looking for an entirely different species of stonefly. But this species was different, and Waters knew it. It’s flightless, chunky, and short, less than two centimetres long. PhD student Brodie Foster, who led its taxonomic description, called it a “relict”. Juvenile stoneflies, called nymphs, live under stones in rapids. At first, researchers found only nymphs of the Maungatua stonefly, so they reared a male to adulthood to study. DNA analysis confirmed it as a new species, named Zelandoperla maungatuaensis. Landcare Research considers nymphs from the Zelandoperla genus to be indicators of good water quality—they’re among the first species to disappear from an unhealthy stream.
Chytrid fungus is the Genghis Khan of the amphibian world: it has spent the past 50 years invading nations one by one, slaughtering as it goes. It has spread to more than 60 countries, wiped out 90 species, and caused significant population declines in more than 500 species, according to an international study led by the Australian National University. The fungus, which eats the skin of amphibians, is responsible for the world’s greatest biodiversity loss due to a disease. Researchers say it should be considered one of the most damaging invasive species in the world—up there with rats and cats in terms of the number of species it endangers. Though chytrid is present in New Zealand and Australia, one nearby land mass remains a sanctuary: New Guinea, which is home to six per cent of the world’s frog species. In June, a team of 30 international experts published a paper in Frontiers in Ecology and the Environment calling for greater support and protection for New Guinea’s island haven.
Three fathers, two mothers, one father and two mothers—all are naturally occuring parent combinations for honeybees. Honeybees are haplodiploid, which means that females hatch from fertilised eggs (and have two parents) while males hatch from unfertilised eggs (and have no father). This makes it possible for new forms of reproduction to occur, and new research into bees’ DNA, published in Biology Letters last November, found that they can have multiple parents of various sexes. Researchers estimate that one to two per cent of bees are born this way—they’re known as sex mosaics, or gynandromorphs, and have a mixture of male and female characteristics.
A citizen-science project to spot Otago skinks will help a Dunedin PhD student collect valuable data about the weather conditions that they prefer. Jo Virens set up eight cameras in Redbank Reserve to photograph Otago skink habitat every minute. The result: 750,000 images. Virens now needs help identifying which pictures feature skink appearances. By plotting the reptiles’ activity alongside detailed data on wind, solar radiation, temperature and humidity, Virens will be able to figure out which temperature conditions best suit them. “It’s all about how that affects body temperature, they’re going to be wanting to maintain a body temperature of probably around 25 to 35 degrees.” Then, using localised weather projections for the next 100 years, Virens will be able to create a skink forecast: will there be skink-friendly weather, encouraging them to bask all day long? Or will they need to move to new habitat to survive? There aren’t many skinks to spot—they’re endangered—but they pop into the frame often enough to tempt a viewer to spot just one more. “I’m not expecting it to be that entertaining,” says Virens. “I’m hoping the challenge behind it is what’s going to be appealing about it.” Otago skinks have black and gold markings reminiscent of lichen growing on rock, and reach up to 30 centimetres in length. Their patterns are unique—individual skinks can be identified from pictures of their face markings. Not that they always come that close in Virens’ pictures. Virens has set up the project on citizen-science platform Zooniverse—anyone can view 10 time-lapse images at a time, and flag when Otago skinks appear. Follow this shortcut to access them: nzgeo.com/skink The skinks are hard to spot, warns Virens, so look closely. “The beta test revealed that false negatives—people missing skinks—were relatively common, whereas false positives—people saying they saw a skink when there wasn’t one—practically never happened.”
Fish have been forming shoals since at least the Eocene Epoch, according to this fossil of 259 tiny, extinct Erismatopterus levatus, which lived about 50 million years ago in giant lakes that covered Wyoming, Colorado and Utah in the United States. By analysing the positions and swimming directions of the fish, researchers from Arizona State University found their group behaviour to be the same as fish species today: they avoid straying too far from the shoal and swimming too close to each other. Communication and behaviour are usually absent from the fossil record, but in this case, a mystery remains: how were these fish preserved mid-swim?
Spearfishers are taking aim at freshwater pests instead of dwindling marine species.
Why did hundreds of dead kororā—little blue penguins—wash up on beaches around the country two summers ago? Has their fate got anything to do with the weather? Or has it got something to do with us?
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