A deadly fungus threatens to wipe out 100 frog species – here’s how it can be stopped


Deborah Bower, University of New England and Simon Clulow, Macquarie University

What would the world be like without frogs? Earth is in its sixth mass extinction event and amphibians are among the hardest hit.

But in the island of New Guinea, home to 6% of the world’s frog species, there’s a rare opportunity to save them from the potential conservation disaster of a chytrid fungus outbreak.

The amphibian chytrid fungus is a microscopic, aquatic fungus that infects a protein in frog skin. It interferes with the balance of electrolytes and, in turn, effectively gives frogs a heart attack.




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Tiny frogs face a troubled future in New Guinea’s tropical mountains


If the amphibian chytrid fungus invades New Guinea, we estimate 100 species of frogs could decline or become extinct. This disease, which emerged in the 1980s, has already wiped out 90 species of frogs around the world.

The New Guinean horned land frog, Sphenophryne cornuta, with young. These frogs are under threat from a fungus that has wiped out 90 frog species around the world.
Stephen Richards

Collaborating with 30 international scientists, we developed a way to save New Guinea’s frog species from a mass extinction, one that’s predictable and preventable. We need urgent, unified, international action to prepare for the arrival of the deadly fungus, to slow its spread after it arrives and to limit its impact on the island.

It’s rare we can identify a conservation disaster before it occurs, but a long history of amphibian declines in Australia and South America has equipped us with the knowledge to protect areas where the amphibian chytrid fungus is yet to reach.

Why we should care about frogs

Like Australian frogs, New Guinea frogs may be particularly vulnerable to the chytrid fungus. These frogs share a close genetic relationship suggesting that, if exposed, New Guinea frogs may respond similarly to Australian ones, where around 16% of frog species are affected.

Impacted frogs include corroboree frogs, Australian lacelid frogs and green and golden bell frogs.




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Australian endangered species: Southern Corroboree Frog


Losing so many species can have many terrible impacts. Tadpoles and frogs are important because they help recycle nutrients and break down leaf litter. They are also prey for larger mammals and reptiles, and predators of insects, invertebrates and small vertebrates. They help keep insect plagues, such as those from flies and mosquitoes, in check.

Frogs are also an important source of human medical advancements – they were even used for a human pregnancy test until the 1950s.

A call to action to protect frogs

Frogs are one of the most threatened groups of species in the world – around 40% are threatened with extinction.

And species conservation is more expensive once the species are threatened. They can be more costly to collect and more precious to maintain, with a greater need for wider input from recovery groups to achieve rapid results.

In our study, we highlight the increased costs and requirements for establishing captive breeding for two species of closely related barred frog, one common and one threatened. We determined that waiting until a species is threatened dramatically increases the costs and effort required to establish a successful breeding program. The risks of it failing also increase.

Our research draws on lessons learned from other emerging diseases and approaches taken in other countries. By addressing the criteria of preparedness, prevention, detection, response and recovery, we detail a call for action to protect the frogs of New Guinea. It will require dedicated funding, a contingency plan for the likely, eventual arrival of the disease and a task force to oversee it.




Read more:
Frogs v fungus: time is running out to save seven unique species from disease


This task force would oversee active monitoring for disease and prepare an action plan to implement on the disease’s arrival. We have already begun to establish facilities that can handle captive breeding and gene banking for frogs in collaboration with PNG counterparts.

The need for amphibian conservation in New Guinea also presents an opportunity for investment and training of local scientists. More species unknown to science will be described and the secret habits of these unique frogs will be discovered before they are potentially lost.

Conservation in New Guinea is complicated

The island of New Guinea is governed by Papua New Guinea on the eastern side and Indonesia on the western side. So it will take a coordinated approach to reduce risks in both countries for successful biosecurity.

Historically, New Guinea has had little import or tourism. But as the country develops, it becomes more at risk of emerging diseases through increased trade and and entry of tourists from chytrid-infected regions, especially with little biosecurity at entry ports.

What’s more, many species there are unknown to science and few ecological studies have documented their habitat requirements. Unlike Australia, many of New Guinea’s frogs have adapted for life in the wet rainforest.

Rather than developing into tadpoles that live in water, more than 200 frog species in New Guinea hatch from their eggs as fully formed baby frogs. It’s difficult for us to predict how the amphibian chytrid fungus will affect these frogs because Australia has only a handful of these types of species.

We don’t know how to remove the amphibian chytrid fungus from large areas once it has invaded, so strict biosecurity and conservation contingency planning is needed to protect New Guinea’s frogs.




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For example, all incoming goods into New Guinea should be inspected for possible hitchhiker frogs that could carry chytrid. Camping or hiking equipment carried by tourists should also be closely inspected for attached mud, which could harbour the pathogen, as is the case in Australia.

International researchers have experience in emerging amphibian diseases. Papua New Guineans and Indonesians have traditional and ecological expertise. Together we have the opportunity to avert another mass decline of frogs. Without taking action, we could lose a hundred more species from the world and take another step towards mass extinction.The Conversation

Deborah Bower, Lecturer in Ecosystem Rehabilitation, University of New England and Simon Clulow, MQ Research Fellow, Macquarie University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Deadly frog fungus has wiped out 90 species and threatens hundreds more



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The Mossy Red-eyed Frog is among hundreds of species threatened with extinction at the hands of chytrid fungus.
Jonathan Kolby/Honduras Amphibian Rescue and Conservation Center

Benjamin Scheele, Australian National University and Claire Foster, Australian National University

It started off as an enigma. Biologists at field sites around the world reported that frogs had simply disappeared. Costa Rica, 1987: the golden toad, missing. Australia, 1979: the gastric brooding frog, gone. In Ecuador, Arthur’s stubfoot toad was last seen in 1988.

By 1990, cases of unexplained frog declines were piling up. These were not isolated incidents; it was a global pattern – one that we now know was due to chytridiomycosis, a fungal disease that was infecting and killing a huge range of frogs, toads and salamanders.

Our research, published today in Science, reveals the global number of amphibian species affected. At least 501 species have declined due to chytrid, and 90 of them are confirmed or believed extinct.




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When biologists first began to investigate the mysterious species disappearances, they were at a loss to explain them. In many cases, species declined rapidly in seemingly pristine habitat.

Species declines typically have obvious causes, such as habitat loss or introduced species like rats. But this was different.

The first big breakthrough came in 1998, when a team of Australian and international scientists led by Lee Berger discovered amphibian chytrid fungus. Their research showed that this unusual fungal pathogen was the cause of frog declines in the rainforests of Australia and Central America.

However, there were still many unknowns. Where did this pathogen come from? How does it kill frogs? And why were so many different species affected?

After years of painstaking research, biologists have filled in many pieces of the puzzle. In 2009, researchers discovered how chytrid fungus kills frogs. In 2018, the Korean peninsula was pinpointed as the likely origin of the most deadly lineage of chytrid fungus, and human dispersal of amphibians suggested as a likely source of the global spread of the pathogen.

Yet as the mystery was slowly but surely unravelled, a key question remained: how many amphibian species have been affected by chytrid fungus?

Early estimates suggested that about 200 species were affected. Our new study reveals the total is unfortunately much larger: 501 species have declined, and 90 confirmed or suspected to have been killed off altogether.

The toll taken by chytrid fungus on amphibians around the world. Each bar represents one species; colours reveal the extent of population declines.
Scheele et al. Science 2019

Devastating killer

These numbers put chytrid fungus in the worst league of invasive species worldwide, threatening similar numbers of species as rats and cats. The worst-hit areas have been in Australia and Central and South America, which have many different frog species, as well as ideal conditions for the growth of chytrid fungus.

Large species and those with small distributions and elevational ranges have been the mostly likely to experience severe declines or extinctions.

Together with 41 amphibian experts from around the world, we pieced together information on the timing of species declines using published records, survey data, and museum collections. We found that declines peaked globally in the 1980s, about 15 years before the disease was even discovered. This peak coincides with biologists’ anecdotal reports of unusual amphibian declines that occurred with increasing frequency in the late 1980s.

Encouragingly, some species have shown signs of natural recovery. Twelve per cent of the 501 species have begun to recover in some locations. But for the vast majority of species, population numbers are still far below what they once were.

Most of the afflicted species have not yet begun to bounce back, and many continue to decline. Rapid and substantial action from governments and conservation organisations is needed if we are to keep these species off the extinct list.




Read more:
Saving amphibians from a deadly fungus means acting without knowing all the answers


In Australia, chytrid fungus has caused the decline of 43 frog species. Of these, seven are now extinct and six are at high risk of extinction due to severe and ongoing declines. The conservation of these species is dependent on targeted management, such as the recovery program for the iconic corroboree frogs.

The southern corroboree frog: hopefully not a disappearing icon.
Corey Doughty

Importantly, there are still some areas of the world that chytrid has not yet reached, such as New Guinea. Stopping chytrid fungus spreading to these areas will require a dramatic reduction in the global trade of amphibians, as well as increased biosecurity measures.

The unprecedented deadliness of a single disease affecting an entire class of animals highlights the need for governments and international organisations to take the threat of wildlife disease seriously. Losing more amazing species like the golden toad and gastric brooding frog is a tragedy that we can avoid.The Conversation

Benjamin Scheele, Research Fellow in Ecology, Australian National University and Claire Foster, Research Fellow in Ecology and Conservation, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The glowing ghost mushroom looks like it comes from a fungal netherworld



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The ghost fungus emits an eerie green glow.
Alison Pouliot, Author provided

Alison Pouliot, Australian National University

Sign up to Beating Around the Bush, a series that profiles native plants: part gardening column, part dispatches from country, entirely Australian.


It’s worth tolerating the mosquitoes and the disconcerting rustle of unseen creatures that populate forests after dark, for the chance to encounter the eerie pale green glow of a less-known inhabitant.

Australia is a land of extremes, of curious organisms with quirky adaptations. Even our ghosts are more perplexing than your regular spook, and you don’t need a Geiger counter or infrared camera to track them down. Ghosts feature fantastically in folklore across the globe, but Australia’s ghost collective has a special fungal addition. Stealing the limelight, or rather the twilight, is the ghost fungus, Omphalotus nidiformis.

Ghost fungi are large, common and conspicuous, yet they manage to escape the gaze of most. As interest in fungi grows in Australia, the ghost fungi is getting a curious new look-in.



The Conversation/Alison Pouliot

Fungi are well known for their perplexing traits and peculiar forms. One of the more mesmerising – and other-worldly – traits is luminosity. A conspicuous quirk, luminosity has been recognised for a good while. Aristotle (384–322 BC) was among the first to have reported terrestrial bioluminescence (bios meaning living and lumen meaning light) in the phenomenon of “glowing wood” or “shining wood” –luminescent mycelia in decomposing wood.

However, well before Aristotle’s time, Aboriginal Australians knew about the luminescence of fungi. Early settlers in Australia recorded the reactions of different Aboriginal groups to what we think was the ghost fungus. Some, such as the Kombumerri of southeastern Queensland, associated luminous fungi with evil spirits and supernatural activities of Dreamtime ancestors. West Australian Aboriginal people referred to the ghost fungus as Chinga, meaning spirit.

Ghost fungi often grow en masse in large overlapping clusters around the bases of both living and dead trees.
Alison Pouliot, Author provided

Similarly in Micronesia, some people destroyed luminous fungi believing them to be an evil omen, while others used them in body decoration, especially for intimidating enemies.

In California, miners believed them to mark the spot where a miner had died. This seemingly inexplicable glowing trait gave rise to rich and colourful folk histories.

Lighting up the night

The ghost fungus contains a light-emitting substance called luciferin (lucifer meaning light-bringing). In the presence of oxygen, luciferin is oxidised by an enzyme called luciferase. As a result of this chemical reaction, energy is released as a greenish light. The light from the ghost fungus is often subtle and usually requires quite dark conditions to see. To experience ghost fungi at their most spectacular you need to allow your eyes time to adjust to the darkness, and don’t use a torch.

Ghost fungi have been widely recorded across Australia, especially in the forests of the south-eastern seaboard. They often appear in large overlapping clusters around the bases of a variety of trees, commonly Eucalyptus, but also Acacia, Hakea, Melaleuca, Casuarina and other tree genera as well as understorey species.

The large funnel-shaped mushrooms (the reproductive part of the fungus) are variable in form and colour, but are mostly white to cream coloured with various shades of brown, yellow, green, grey, purple and black, usually around the centre of the cap. On the underside, the lamellae (radiating plates that contain the spores) are white to cream coloured and extend down the stipe (stem).

This adaptable fungus obtains its tucker as both a weak parasite of some tree species and as a saprobe, which means it gets nutrition from breaking down organic matter such as wood.

Young ghost fungi can appear remarkably similar to edible oyster (Pleurotus) mushrooms, but be warned, ghost fungi are toxic.
Alison Pouliot, Author provided

Although fungal bioluminescence has been well documented, little research has been done to establish why fungi go to the trouble of glowing. While some experiments have shown that bioluminescence attracts spore-dispersing insects to particular fungi, this appears not to be the case with the ghost fungus.

Researchers who tested whether insects are more readily attracted to the ghost fungus concluded that bioluminescence is more likely to be an incidental by-product of metabolism, rather than conferring any selective advantage.

Those who find this scientific explanation rather unimaginative might prefer to stick with the theory that these fungi help guide fairies (or perhaps a bilby or bandicoot) through the darkened forest.

If you stumble across ghost fungi in daylight, however, they look far less puzzling. It does bear a superficial resemblance to the delicious oyster mushroom (and were once classified in the same genus), but unfortunately they are toxic. Ghost fungi possess a powerful emetic that causes nausea and vomiting. (And who knows, it might even cause you to glow terrifyingly green…)

Returning to darkness

We live in the Age of Illumination, plagued by light pollution. Earth’s nights are getting brighter and many scientists are concerned about the effects on wildlife as well as how they stymie human appreciation of nature. Artificial lights disorient birds, especially those that migrate at night and other species such as hatching turtles that confuse artificial light with that of the moon. Exposure to artificial light also affects human health.

A nighttime wander through the forest reveals its nocturnal inhabitants and may reward one with the pleasures of finding ghost fungi. Only in darkness is their magic revealed.


Alison Pouliot will be launching her book on Australian fungi, The Allure of Fungi, in Melbourne, Daylesford, Apollo Bay and Shellharbour. For more details on these events go here.

Sign up to Beating Around the Bush, a series that profiles native plants: part gardening column, part dispatches from country, entirely Australian.The Conversation

Alison Pouliot, , Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Fighting frog fungus: Lee Berger wins PM’s Life Scientist 2018 award



File 20181016 165903 16u8i1s.jpg?ixlib=rb 1.1
In 1998 Lee Berger identified a skin fungus as the cause of unexplained mass frog deaths.
Prime Minister’s Prizes for Science/WildBear

Lee Berger, University of Melbourne and Lee Francis Skerratt, University of Melbourne

Lee Berger is the 2018 recipient of the Frank Fenner Prize for Life Scientist of the Year, one of the Prime Minister’s Prizes for Science announced on October 17.

Lee’s research identified the cause of mysterious and devastating mass frog extinctions that spread across the world starting in the 1970s: it was a skin fungus.

With her colleague Lee Skerratt, here she describes the work that led to her prize, and what is still to be achieved for frog and wildlife conservation in Australia and across the world.


Combating fungi in frogs – why is this important?

Chytridiomycosis might be the worst disease in history. In a matter of decades, the illness cut a swathe through hundreds of species of frogs, causing mass extinctions as it spread out of Asia into Australia and the Americas.

Our research was the first to identify the cause – a novel chytrid fungus called Batrachochytrium dendrobatidis – but finding ways to combat the disease requires a lot more work.

Infected frogs are lethargic and experience excess skin shedding (this species is Mixophyes fasciolatus).
Lee Berger, Author provided

Here in Australia, six species have already been driven extinct, and another seven are on the brink. Fortunately, in Australia we also have the unique expertise and perspective to prevent further losses if we devote adequate resources to the problem.




Read more:
Frogs v fungus: time is running out to save seven unique species from disease


The keys to our research success have been a cross-disciplinary approach and a focus on delivering conservation outcomes.

Frog declines had been seen around the world from the late 1970s on, but it wasn’t until 1998 that we identified the chytrid fungus as the cause.

Parts of the fungus poke through an infected frog’s skin – as seen here under scanning electron microscope.
Lee Berger, Author provided

Why had nobody else figured this out before?

Discovering the fungus on the skin of frogs was not rocket science, but rather applying the methods from one discipline to a problem in another. An outbreak investigation approach – using the tools of medicine for frog conservation – allowed us to diagnose the cause of the frog deaths.

The main reason this approach was tried in Australia was the broad knowledge and interest of the late Rick Speare, an extraordinarily eclectic scientist, medical doctor and vet. (Like the prize’s namesake Frank Fenner, he was comfortable using his medical expertise for the environment.)

Rick’s help was sought by Keith McDonald, a chief ranger of Queensland and a herpetologist. Keith was concerned about the health of North Queensland frogs after witnessing major declines in the south.

After looking at the pattern of declines the pair thought they saw the trail of an unknown infectious, waterborne disease. They applied for funds to search for a disease.

Green-eyed treefrogs (Litoria serrata) in the Queensland rainforest have declined due to chytridiomycosis.
Lee Skerratt, Author provided

The idea that an infectious disease might be responsible for frog declines met resistance because of the belief that a pathogen can never cause extinction, because hosts will evolve resistance. So while Rick and Keith did obtain funding to tackle this urgent global mystery, it was only enough to support a single PhD student.

That PhD student was me, Lee Berger. To cut a long story short, my work in pathology and disease transmission experiments in frogs led to our conclusion that a novel and unusual fungus in the frogs’ skin caused a fatal disease and the mass amphibian deaths seen in North Queensland. As this was the first fungus from the phylum Chytridiomycota found to cause disease in a vertebrate, I had to develop many new methods to be able to further study the disease.

So in summary, it was about 20 years after global amphibian declines began that we discovered chytridiomycosis as the cause of the population crashes. It took about another ten years for the disease to be accepted as the prime cause of declines.

After the discovery, what came next?

In subsequent years our research has continued towards the more challenging goal of finding solutions to manage this issue.

Our small multidisciplinary One Health Research Group has tackled diverse questions to reduce the spread and the impact. Questions such as:

Now we are focused on understanding immunity to improve survival rates of the most threatened species of frogs in the wild.

This work has only been possible due to the extraordinary dedication of our students and staff and the collaboration with specialist scientists such as herpetologists, molecular biologists, immunologists, physiologists and others who have lent their expertise.

Common mistfrogs (Litoria rheocola) in the Queensland rainforest have also declined due to chytridiomycosis.
Lee Skerratt, Author provided

What does this mean for Australia’s wildlife?

Our research has clearly shown that introduced diseases can have catastrophic impacts for conservation, much like the arrival of feral predators. In fact, disease can cause extinction much more quickly than predators, within months rather than years. The catastrophe of invasive species is a cost of globalisation that will be ongoing unless we respond.

The responsibility for wildlife lies with environment departments, but because health expertise is in other institutes, wildlife health can fall between the cracks.

We argue that continued support for bodies such as Wildlife Health Australia (WHA) is important. We also need a centre of expertise for outbreak investigation and strategic research to develop new tools for wildlife health management.

Biodiversity will miss out unless we support research that promises no direct and fast commercial return but benefits our nation in the longer term. In particular, and most urgently, Australia must save its frogs before it is too late.


Other winners in the 2018 Prime Ministers Science Prizes are: The Conversation

  • Prime Minister’s Prize for Science: Kurt Lambeck
  • Prime Minister’s Prize for Innovation: The Finisar team
  • Frank Fenner Prize for Life Scientist of the Year: The Finisar team
  • Malcolm McIntosh Prize for Physical Scientist of the Year: Jack Clegg
  • Prime Minister’s Prize for New Innovators: Geoff Rogers
  • Prime Minister’s Prize for Excellence in Science Teaching in Primary Schools: Brett Crawford
  • Prime Minister’s Prize for Excellence in Science Teaching in Secondary Schools: Scott Sleap

Lee Berger, , University of Melbourne and Lee Francis Skerratt, , University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Scientists create new building material out of fungus, rice and glass


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Fungal bricks have the potential to create safer and more sustainable buildings.
V Anisimov / Shutterstock

Tien Huynh, RMIT University and Mitchell Jones, RMIT University

Would you live in a house made of fungus? It’s not just a rhetorical question: fungi are the key to a new low-carbon, fire-resistant and termite-deterring building material.

This type of material, known as a mycelium composite, uses the Trametes versicolor fungus to combine agricultural and industrial waste to create lightweight but strong bricks. It’s cheaper than synthetic plastics or engineered wood, and reduces the amount of waste that goes to landfill.




Read more:
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What a fun guy

Fungal brick prototypes made from rice hulls and glass fines waste.
Tien Huynh, Author provided

Working with our colleagues, we used fungus to bind rice hulls (the thin covering that protects rice grains) and glass fines (discarded, small or contaminated glass). We then baked the mixture to produce a new, natural building material.

Making these fungal bricks is a low-energy and zero-carbon process. Their structure means they can be moulded into many shapes. They are therefore suited to a variety of uses, particularly in the packaging and construction industries.

A staple crop for more than half the world’s population, rice has an annual global consumption of more than 480 million metric tonnes and 20% of this is comprised of rice hulls. In Australia alone, we generate about 600,000 tonnes of glass waste a year. Usually these rice hulls and glass fines are incinerated or sent to landfill. So our new material offers a cost-effective way to reduce waste.

Fire fighter

Fungal bricks make ideal fire-resistant insulation or panelling. The material is more thermally stable than synthetic construction materials such as polystyrene and particleboard, which are derived from petroleum or natural gas.

Rice hulls, glass fines and the mixture of rice, glass and fungus, before baking.
Wikipedia/Tien Huynh, Author provided

This means that fungal bricks burn more slowly and with less heat, and release less smoke and carbon dioxide than their synthetic counterparts. Their widespread use in construction would therefore improve fire safety.

Thousands of fires occur every year and the main causes of fatalities are smoke inhalation and carbon monoxide poisoning. By reducing smoke release, fungal bricks could allow more time for escape or rescue in the event of a fire, thus potentially saving lives.




Read more:
How can we build houses that better withstand bushfires?


Bug battler

Termites are a big issue: more than half of Australia is highly susceptible to termite infestations. These cost homeowners more than A$1.5 billion a year.

Our construction material could provide a solution for combating infestations, as the silica content of rice and glass would make buildings less appetising to termites.




Read more:
Hidden housemates: the termites that eat our homes


The use of these fire-and-termite-resistant materials could simultaneously revolutionise the building industry and improve waste recycling.

Figure 3. Termite infestation zones in Australia.
termitesonline.com.au, Author provided

This is an exciting time to get creative about our waste. With China no longer buying Australia’s recycling – and new rules reducing plastic use in Australian supermarkets – we have the chance to move in line with communities in Japan, Sweden and Scotland that have near-zero waste.

Fungal bricks could be just one example of the creative thinking that will help us get there.


The Conversation


Read more:
The next step in sustainable design: Bringing the weather indoors


Tien Huynh, Senior Lecturer in the School of Sciences, RMIT University and Mitchell Jones, PhD Student, RMIT University

This article was originally published on The Conversation. Read the original article.

Some tropical frogs may be developing resistance to a deadly fungal disease – but now salamanders are at risk



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Panamanian golden frogs (Atelopus zeteki) are listed as critically endangered, and may be extinct in the wild.
Jeff Kubina, CC BY-SA

Louise Rollins-Smith, Vanderbilt University

My office is filled with colorful images of frogs, toads and salamanders from around the world, some of which I have collected over 40 years as an immunologist and microbiologist, studying amphibian immunity and diseases. These jewels of nature are mostly silent working members of many aquatic ecosystems.

The exception to the silence is when male frogs and toads call to entice females to mate. These noisy creatures are often wonderful little ventriloquists. They can be calling barely inches from your nose, and yet blend so completely into the environment that they are unseen. I have seen tropical frogs in Panama and native frogs of Tennessee perform this trick, seemingly mocking my attempts to capture them.

My current research is focused on interactions between amphibians and two novel chytrid pathogens that are linked to global amphibian declines. One, Batrachochytrium dendrobatidis ( abbreviated as Bd), has caused mass frog dieoffs around the world. Recently my lab group contributed to a study showing that some species of amphibians in Panama that had declined due to Bd infections are recovering. Although the pathogen has not changed, these species appear to have developed better skin defenses than members of the same species had when Bd first appeared.

This is very good news, but those who love amphibians need to remain vigilant and continue to monitor these recovering populations. A second reason for concern is the discovery of a closely related chytrid, Batrachochytrium salamandrivorans (Bsal), which seems to be more harmful to salamanders and newts.

Amphibian chytrid fungus has been detected in at least 52 countries and 516 species worldwide.
USDA Forest Service

Global frog decline

More than a decade ago, an epidemic of a deadly disease called chytridiomycosis swept through amphibian populations in Panama. The infection was caused by a chytrid fungus, Batrachochytrium dendrobatidis. Scientists from a number of universities, working with the Smithsonian Tropical Research Institute in Panama, reported that chytridiomycosis was moving predictably from west to east from Costa Rica across Panama toward Colombia.

I was part of an international group of scientists, funded by the National Science Foundation, who were trying to understand the disease and whether amphibians had effective immune defenses against the fungus. Two members of my lab group traveled to Panama yearly from 2004 through 2008, and were able to look at skin secretions from multiple frog species before and after the epidemic of chytridiomycosis hit.

Many amphibians have granular glands in their skin that synthesize and sequester antimicrobial peptides (AMPs) and other defensive molecules. When the animal is alarmed or injured, the defensive molecules are released to cleanse and protect the skin.

Through mechanisms that remain a mystery, we observed that these skin defenses seemed to improve after the pathogen entered the amphibian communities. Still, many frog populations in this area suffered severe declines. A global assessment published in 2004 showed that 43 percent of amphibian species were declining and 32 percent of species were threatened.

In Panama, Smithsonian scientists operate the largest amphibian conservation facility of its kind in the world.

Signs of resistance

In 2012-2013, my colleagues ventured to some of the same sites in Panama at which amphibians had disappeared. To our great delight, some of the species were partially recovering, at least enough so that they could be found and sampled again.

We wanted to know whether this was happening because the pathogen had become less virulent, or for some other reason, including the possibility that the frogs were developing more effective responses. To find out, we analyzed multiple measures of Bd‘s virulence, including its ability to infect frogs that had never been exposed to it; its rate of growth in culture; whether it had undergone genetic changes that would show loss of some possible virulence characteristics; and its ability to inhibit frogs’ immune cells.

As our group recently reported, we found that the pathogen had not changed. However, we were able to show that for some species, frog skin secretions we collected from frogs in populations that had persisted were better able to inhibit the fungus in a culture system than those from frogs that had never been exposed to the fungus.

The prospect that some frog species in some places in Panama are recovering in spite of the continuing presence of this virulent pathogen is fantastic news, but it is too soon to celebrate. The recovery process is very slow, and scientists need to continue monitoring the frogs and learn more about their immune defenses. Protecting their habitat, which is threatened by deforestation and water pollution, will also be a key factor for the long-term survival of these unique amphibian species in Panama.

If Bsal fungus spreads to North America, it could wipe out species like this Northern Slimy Salamander (Plethodon glutinosus).
Marshal Hedin, CC BY

Salamanders (and frogs) at risk

On a global scale, Bd is not the only threat. A second pathogenic chytrid fungus called Batrachochytrium salamandrivorans (abbreviated as Bsal) was recently identified in Europe, and has decimated some salamander populations in the Netherlands and Belgium. This sister species probably was accidentally imported into Europe from Asia, and seems to be a greater threat to salamanders than to frogs or toads.

Bsal has not yet been detected in North America. I am part of a new consortium of scientists that has formed a Bsal task force to study whether it could become invasive here, and which species might be most adversely affected.

In January 2016 the U.S. Fish and Wildlife Service listed 201 salamander species as potentially injurious to wildlife because of their their potential to introduce Bsal into the United States. This step made it illegal to import or ship any of these species between the continental United States, the District of Columbia, Hawaii, the Commonwealth of Puerto Rico or any possession of the United States.

The Bsal task force is currently developing a strategic plan that lists the most urgent research needs to prevent accidental introduction and monitor vulnerable populations. In October 2017 a group of scientists and conservation organizations urged the U.S. government to suspend all imports of frogs and salamanders to the United States.

The ConversationIn short, it is too early to relax. There also are many other potential stressors of amphibian populations including climate change, decreasing habitats and disease. Those of us who cherish amphibian diversity will continue to worry for some time to come.

Louise Rollins-Smith, Associate Professor of Pathology, Microbiology and Immunology, Vanderbilt University

This article was originally published on The Conversation. Read the original article.

Lichens may be a symbiosis of three organisms; a new Order of fungus named


Susan Lawler, La Trobe University

There is big news in the world of lichens. These slow growing organisms have long been known to be a collaboration between a fungus and a photosynthetic algae or cyanobacteria. A recent publication in Science may have changed all that.

Researchers have discovered another fungus living in the tissues of lichens. Unlike the dominant fungal type, also known as Ascomycetes, the new fungus is a Basidiomycete that exists as single cells, more closely related to yeast. A survey has found these new fungal cells in 52 genera of lichens, raising the prospect of a previously undetected third partner in the ancient symbiosis.

Interestingly, despite many attempts, it has never been possible to synthesise lichen in the laboratory by combining the two known partners, and now we might know why. Lichenologists have always recognised a mycobiont (fungal partner) and a photobiont (the photosynthetic organism that makes food) and now we may have to find a word for the new fungal component.

Toby Spribille of the University of Graz in Austria and his colleagues were trying to understand why two species of lichen that were made up of the same species of mycobiont and photobiont were differently coloured and contained varying levels of a toxin known as vulpinic acid.

Using an approach that examined the messenger RNAs produced by the organism, they tried to find the genes that produced the toxin, but neither the mycobiont or the photobiont had genes that matched the transcript. By broadening their search to include other types of fungi, they found genes belonging to a rare fungus called a Cystobasidiomycete.

Unable to see the cells responsible for this unusual finding, they used fluorescent in situ hybridisation (FISH) to light up cells containing genes for the algae, the ascomycete and the cystobasidiomycete. By linking different colours to each organism, they produced videos showing the distribution of each cell type. The new fungus existed as single cells inside the cortex, where it may play a structural role as well as providing chemical defence.

It is hard to overstate the importance of this discovery. Spribille was quoted in the New York Times as saying that lichens are as diverse as vertebrates. And yet we did not know until now that the symbiosis that allows lichens to exist has more than two partners.

The authors have described a new order of fungi called the Cyphobasidiales. It is not everyday that scientists are able to add new taxa at such a high level. It is like discovering the Primates. By creating a phylogenomic tree and applying a molecular clock, they found that this group has been around for 200 million years, probably since the beginning of lichens.

The 52 genera that have been examined thus far are widespread (on six continents) but are still a small portion of lichens, so there may be more to discover. Interestingly, the continent that is not included is Australia. Perhaps we do not have enough lichenologists to provide samples to the international community. It is possible that some lichens do not contain this new order of fungi. What is not in doubt is that now scientists will be looking at lichens more closely.

Lichens grow very slowly. Individuals can be hundreds or even thousands of years old. Now it seems that our knowledge of this ancient symbiosis has also grown slowly, as it has taken 150 years to find the third partner.

Given the sophisticated techniques required to untangle this conundrum, I suppose it was not possible to know about the silent partner, the yeast in the mix, until now. But it certainly gives rise to some exciting science.

The Conversation

Susan Lawler, Senior Lecturer, Department of Ecology, Environment and Evolution, La Trobe University

This article was originally published on The Conversation. Read the original article.