Philippa Kaur

The African pitta’s isiZulu name unothingo — meaning rainbow — is a reference to its brightly coloured plumage.Credit: Richard Flack/NaturePL

Researchers hope that the Rudd’s lark’s new isiZulu name — unonhlozi — could bolster conservation efforts to protect the small endangered lark (Heteromirafra ruddi). Unonhlozi means eyebrows, a nod to the bird’s wizard-worthy eyebrows, and it is one of many new isiZulu words that researchers have created for South Africa’s birds.“We must all engage with our natural heritage in any language we choose,” says Nandi Thobela, a manager at the non-governmental organization BirdLife South Africa in Johannesburg, and co-author of a paper published last week in the South African Journal of Science1. The article describes how the researchers developed isiZulu terminology for all 876 wild bird species found in the country.The effort took more than a decade and involved numerous meetings to agree on the names, which were also made available for public comment before inclusion in the definitive list.Lolie Makhubu-Badenhorst, director of the Multilingualism Education Project at the University of Cape Town, South Africa, welcomed the research. “Such a publication contributes and affirms the use of our South African Indigenous languages, particularly in the field.”New terminologyIsiZulu is one of about 2,000 languages spoken in Africa, the overwhelming majority of which have been ignored by modern science. This can hamper research in many disciplines, including conservation science. Monitoring wild birds is a good way to gauge ecosystem health. But many African languages, including 10 of South Africa’s 12 official languages, do not have official names for different species, which can cause confusion.Since 2011, a team of scientists, language specialists and Zulu bird guides have been working with Birdlife South Africa to create a complete list of South African bird names in isiZulu.There were already isiZulu names for some birds, such as sparrow (ujolwane) and owl (isikhova), but the team adapted them to describe specific species. For some birds, the team had to coin entirely new names: the African pitta (Pitta angolensis), for example, was given the isiZulu name unothingo (which means rainbow), because of its green back, red undertail, yellow chest and striking face and wing markings. The barred wren-warbler (Calamonastes fasciolatus) is isanyendle, which means ‘like a cricket’, because of its cricket-like call. The names have been added to Cornell University’s global bird-identification app Merlin.The 18 bird guides involved in the naming and their Indigenous knowledge were “absolutely essential” to the project, says co-author Eckhart Buchmann, a retired reproductive-health researcher and avid bird watcher based in South Africa. “How can you choose a bird name if you don’t have in-depth working knowledge of the isiZulu language in environments where birds are appreciated?” he says. “You can only do this if you’re a Zulu person who’s grown up with these creatures around you.”Birdlife South Africa is now turning its attention to Sotho, a language spoken in the north of the country, says Buchmann. More

A periodic cicada in Illinois, where two broods are emerging this month at once.Credit: AJ Mast for Nature

As spring turns to summer in the United States, warming conditions have started to summon enormous numbers of red-eyed periodical cicadas out of their holes in the soil across the east of the country. This year sees an exceptionally rare joint emergence of two cicada broods: one that surfaces every 13 years and another with a 17-year cycle. They last emerged together in 1803, when Thomas Jefferson was US president. This year, billions or even trillions of cicadas from these two broods — each including multiple species of the genus Magicicada — are expected to swarm forests, fields and urban neighbourhoods.To answer readers’ cicada questions, Nature sought help from three researchers. Katie Dana is an entomologist affiliated with the Illinois Natural History Survey at the University of Illinois at Urbana-Champaign. John Lill is an insect ecologist at George Washington University in Washington DC. Fatima Husain is a cognitive neuroscientist at the University of Illinois at Urbana-Champaign. Their answers have been edited for length and clarity.Why do periodical cicadas have red eyes?JL: We’re not really sure. We do know that cicadas’ eyes turn red in the winter before [the insects] come out. The whole coloration pattern in periodical cicadas is very bright: red eyes, black and orange wings. They’re quite different from the annual cicadas, which are green and black, and more camouflaged. It’s a bit of an enigma why the periodical ones are so brightly coloured, given that it just makes them more obvious to predators. There are no associated defences with being brightly coloured — it kind of flies in the face of what we know about bright coloration in a lot of other animals, where usually it’s some kind of signal for toxicity. There also exist mutants with brown, orange, golden or even blue eyes. People hunt for blue-eyed ones; it’s like trying to find a four-leaf clover.

Entomologist Katie Dana collects cicadas in Monticello, Illinois.Credit: AJ Mast for Nature

Can periodical cicadas see in colour?JL: They do see colour. But their eyes are basically non-functional when they’re underground. They’re not investing a lot of energy in making the sort of proteins associated with vision when they’re not needed. And so there’s some dramatic, abrupt developmental switch that happens, that probably coincides with the eye colour changing to red. They now need to be able to use their eyes in a new habitat, which is above ground.Can the two cicada broods interbreed?KD: We know that they can interbreed when introduced to each other in the lab, but it remains to be seen if it actually happens in a wild setting.Do cicadas compete to be heard?JL: Cicadas get together in all-male groups called choruses, and usually in a given tree. Cicadas of a particular species congregate together, put on a big show, and the females are hanging out around the periphery, judging the quality of potential mates. So that’s the reason it’s so loud, but I don’t know the degree to which they’re competing to be heard. They’re obviously trying to distinguish themselves among an already loud group, for the females. And the females are judging something about the quality of the call. But I think the loudness is probably correlated with how vigorous that male is, and might indicate [for a female] good genes to pass on to her offspring, so that she can, in turn, have loud-calling sons that would pass on those genes.
Why locusts congregate in billion-strong swarms — and how to stop them
Can the incessant din of cicadas cause people to develop conditions such as temporary psychosis?FH: I highly doubt that the loud noise of the cicadas causes temporary psychosis. At least, I have not heard of any such cases. People do have hypersensitivity to loud sounds and may find the cicada noises bothersome. Some may find that the noise exacerbates their tinnitus. But for some others, the cicada noise can actually mask their tinnitus.If cicada males buzz to attract females, is it possible that females of one species will be attracted to males of the other species?KD: Noise absolutely brings female cicadas. If you run a lawnmower these days, all the cicadas will flock to you. But once they get closer to each other, there’s a call-and-response that’s more species-specific. The other thing is that in insects, we often talk about lock and key: the male [reproductive organ] is the key and the female [reproductive organ] is the lock, and they have to fit together perfectly. That’s how a lot of insect species make sure they’re mating with the right species.Do any insects thrive on periodical feasts of cicadas?JL: The cicada killer [Sphecius speciosus] is one of the largest native, stinging wasps that we have in this area [the eastern United States]. But the wasps don’t really start foraging until after the periodical cicadas are mostly gone. They mostly feed on the larger, green annual cicadas [family Cicadidae] that come out later in the year. The wasps capture cicadas and paralyse them with their venom and then bring them back to a pre-dug nest in the ground, where they lay an egg upon them. And the cicada serves as live meat for the developing wasp larva that will feed underground on the hapless cicada that gets eaten alive by the wasp larva. More

“Here in Norway, red foxes (Vulpes vulpes) are all over the place. But Arctic foxes (Vulpes lagopus) — the fluffy white cousins of red foxes — survive only high up in the mountains, and meeting one is a really rare occurrence.Researchers estimated that, in 2000, just 40 to 60 Arctic foxes remained in Norway and Sweden. A combination of factors probably explains why the population has collapsed since the start of the twentieth century. For example, fur hunting occurred until the 1930s, and reductions in the numbers of lemmings — a crucial prey animal for the foxes — have also had an impact. Moreover, Arctic foxes live in a fragmented mountain habitat, and the construction of roads has increased the risk of the animals being killed as they disperse from one area to another.Steps taken by the Norwegian Institute for Nature Research are starting to turn things around. These include supplementary feeding of the wild population and running a captive breeding station. Now there are an estimated 560 Arctic foxes across Norway, Sweden and Finland.We have 15 foxes at our captive breeding station near Oppdal in Norway’s Trøndelag county. In this photo, I’m crouching down helping a colleague to transfer a pup from a trap into a handling bag for a health check. We try not to handle them more than we have to, and we prepare them as much as possible for life in the wild. As cute as they are, they are not tame. The 464 young foxes we’ve released since 2006 have done really well. They’ve survived and bred in the wild.At this point, we’ve progressed from trying to save the Arctic fox from extinction in Scandinavia to working on getting its population to be sufficiently large and genetically diverse to sustain itself. We’ve still got a way to go, however, before we can say the species is saved.” More

The emergence is in full swing. Periodical cicadas (Magicicada) are crawling out of the ground in vast numbers — in their trillions, maybe — across swathes of the southeastern and midwestern United States. And researchers, many of whom usually study other insects, are dropping everything to race to sites where they’ve popped up, eager to collect samples and observe the ecological spectacle.“There’s an awful lot that we don’t know” about these insects that spend most of their lives about 60 centimetres underground “in a little mud hole in the dirt”, says Martha Weiss, an entomologist at Georgetown University in Washington DC.This year’s emergence also ups the ante for researchers. Two particular broods — groups of multiple cicada species with the same life cycle appearing above ground in the same year — will sync up for the first time in 221 years. That means the last time they saw daylight together was when the United States was being led by its third president, Thomas Jefferson. Brood XIX, also known as the Great Southern Brood, has been emerging for the past few weeks after 13 years underground, and the more northerly brood XIII has just started popping up after 17 years.Separate territoriesGeographically, the two broods don’t overlap much, although “they come really close together” in central Illinois, near the city of Springfield, says Chris Simon, an evolutionary biologist and entomologist at the University of Connecticut in Storrs. Brood XIX spans the largest area of any known cicada brood, from Maryland to Georgia in the southeast and from Iowa to Oklahoma in the Midwest. Brood XIII, meanwhile, covers northern Illinois, including Chicago.But there is a possible contact zone, and some scientists are flocking to it. Katie Dana, an entomologist affiliated with the Illinois Natural History Survey at the University of Illinois Urbana-Champaign, is hoping to investigate how the two broods might interact and how their mating songs differ. Normally, the pitch of these songs is one way to distinguish between the multiple, visually similar, cicada species that make up a single brood.

One way to distinguish between species of cicada is to collect specimens, freeze them and later sequence their DNA.Credit: AJ Mast for Nature

It could also be a way to distinguish between broods XIX and XIII. They, too, are closely related and look the same, Dana says, making interbreeding possible but really challenging to study in the field.So Dana is now observing their interactions and collecting as many samples as possible, then flash-freezing them for storage. This will allow her and her colleagues to sequence the insects’ DNA later, to help them to distinguish between the broods.“There are gonna be so many graduate-student projects that we’ll have in our freezer after this year,” says Dana, who enthusiastically signs her e-mails “Dr. Ci-Katie-Dae”.Telling the time undergroundOne of the big questions that researchers will seek to answer during this emergence is, how do cicadas keep track of time?When they are above ground, periodical cicadas have a loud and frenzied mating season, after which the females lay eggs in small slits in tree branches. Once the eggs hatch weeks later, the white nymphs fall to the ground like snowflakes, burrow down into the soil and stay there, sucking sap from tree roots for nutrition. They survive and grow like this for a long time — usually prime-numbered stretches of years. The cicadas somehow know to emerge in a particular year once the soil warms up to a balmy 18°C.

Periodical cicadas typically have red eyes, black bodies and orange-tinted wings.Credit: AJ Mast for Nature

Researchers think that having prime-numbered reproduction cycles puts the cicadas conveniently out of sync with the life cycles of various predators that might stalk them. Emerging all at once, in vast numbers, also means that at least some members of a particular brood will survive to have offspring for the next reproduction cycle.But how exactly the insects work out whether 13 or 17 years have passed underground is a mystery. Certainly, they can clock seasonal changes in the trees they feed on, but that can’t be the whole story, Simon says. She suspects that epigenetics — chemical modifications of DNA that control how various genes are expressed — wind the insects’ internal clocks. Specifically, she thinks methyl groups (carbon atoms with three hydrogens attached) are involved. Like Dana, Simon will be collecting samples this year to test her hypothesis.A terrifying fungusAlthough the prime-number trick seems to help cicadas evade predators, it hasn’t fooled a certain parasite. Massospora cicadina fungus infects 13- and 17-year cicadas as they crawl out of the ground, eating through their abdomens and replacing their tissue with plugs of spores. Psychoactive chemicals released by the spores turn the infected cicadas into ‘zombies’, driving them to mate manically to pass spores on to others.
Do insects have an inner life? Animal consciousness needs a rethink
The spores remain dormant in soil for periods matching the prime-numbered cicada cycles, and become activated during an emergence year. But researchers have questions about how this works.Has the fungus evolved its own internal way of tracking 13- and 17-year cycles to keep up with the cicadas? Or is it simply activated by chemical cues released by cicada nymphs as they are about to emerge? To find out, Sierra Raglin, a soil microbial ecologist at the University of Illinois Urbana-Champaign, will locate and collect infected cicadas this year, as well as look for spores in the nearby soil. The soil and its microbiome haven’t been studied much in this context, Raglin says.Cicada emergences are a bolt out of the blue for people and wildlife alike. “Swarms of shrimp-like nymphs crawl out of the ground and cover the trees and the car tyres and the mailboxes,” says Weiss, along with “the legs of passers-by”. Weiss studied her first cicada emergence in 2004; she is now in Illinois to record how brood XIII affects the surrounding ecosystem, including animals such as birds and ants. Piles of cicada carcasses, left behind after the mating is over, offer a feast. This time around, Weiss plans to use ant colonies as an indicator of how nature reacts to this bounty, by studying their foraging patterns and interspecies relationships before, during and after the emergence.“It’s a new experiment every single time,” she says. More

RESEARCH BRIEFINGS
29 May 2024

The genomes of all eight living species of baobab tree (Adansonia sp.) reveal the group’s origin and diversification history. Ecological analyses were incorporated to characterize the baobabs’ past population dynamics and were used to propose protection measures for these iconic species, including the reassessment of their conservation status and the close monitoring of several of Madagascar’s baobab species. More

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Sea urchins enable complex reef ecosystems to thrive by eating algae that would otherwise smother corals. But that delicate natural balance is under threat in the Red Sea and Western Indian Ocean.

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doi: https://doi.org/10.1038/d41586-024-01400-1

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Conservation biology More

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“It’s dirty, hot work picking up blue crabs (Callinectes sapidus). They like murky water, and you need special clothing and equipment to wade through the swampy lagoon here in the Palud – Palù ornithological reserve in Pula, Croatia. It was the end of a long day in September last year when this photo was taken, and I was hot and sweaty under that special clothing. And once you find a crab, you have to be careful not to injure yourself picking it up: either on its sharp lateral spine, or from its very strong claws.I catch the crabs because they are an invasive species, and because it’s my job: as well as working as a biotechnologist, I’m a fisher. Blue crabs are native to Chesapeake Bay in the eastern United States, and they probably made their way here on a ship in the early twentieth century.There has been a large population in the Po river estuary for many years — but a combination of factors, including global warming, has seen them spread down the Adriatic coast since 2022.The crabs are a problem because they eat the bivalves, fish and other crabs that make up the diets of many of the endangered seabirds here at the nature reserve — without that vital source of food, these birds will be even more threatened and we’ll face a serious loss of biodiversity.My colleagues and I at the Juraj Dobrila University of Pula are encouraging local people to eat the crabs, which are sold at the markets. We’ve held awareness activities since long before 2022, in anticipation of the explosion of the invasive population. I know more and more people who collect blue crabs for food.We’re losing the battle against climate change: the changes are too fast and we are far too slow to adapt to them. But I hope by better understanding the biological capital we have available here, we can build a better relationship with nature.” More