I’m searching firegrounds for surviving Kangaroo Island Micro-trapdoor spiders. 6 months on, I’m yet to find any



Jess Marsh, Author provided

Jess Marsh, Murdoch University

This article is part of Flora, Fauna, Fire, a special project by The Conversation that tracks the recovery of Australia’s native plants and animals after last summer’s bushfire tragedy. Explore the project here and read more articles here.


I’m standing on a hill in Kangaroo Island’s Western River Wilderness Protection Area, looking over steep gullies and sweeping hillsides. As far as I can see, the landscape is burnt: bright patches of regrowth contrast with skeletal, blackened trunks. It’s stark, yet strangely beautiful.

It’s late May, five months after the catastrophic summer fires burned 90% of the park. I’m here to assess the damage to some of our tiniest Australians.

Much attention has been given to the plight of Kangaroo Island’s iconic birds and mammals – the Glossy Black Cockatoo and the Kangaroo Island Dunnart, for example. However, the invertebrates – spiders, insects and myriad other groups – have largely been overlooked. These groups contain some of Australia’s most threatened species.

Among the invertebrates listed by the federal government as a priority for intervention is an unassuming, brownish-black spider with squat legs and a body about the size of a A$2 coin. Its name: the Kangaroo Island Micro-trapdoor spider (Moggridgea rainbowi).

The trials it now faces offer an insight into the enormous challenges ahead for invertebrates – the tiny engines of Australia’s biodiversity – in the wake of last summer’s cataclysmic fires.

A female Kangaroo Island Micro-trapdoor spider (Moggridgea rainbowi)
Jess Marsh, Author provided



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The sea-faring spider

The Kangaroo Island Micro-trapdoor spider has an interesting history. It is the only member of its genus found in Australia, its closest relative being in Africa. Studies show it arrived here between 2 and 16 million years ago, likely rafting across the ocean on vegetation! A true voyager.

Kangaroo Island Micro-trapdoor spiders exist only on Kangaroo Island. They live in short, 6cm burrows, built neatly into creek banks. They are slow, calm spiders, spending most of their time in their burrow, determinedly holding the door shut with their fangs.

The females care for their young; I have opened a trapdoor to find 20 tiny spiders living together with their mother. When ready, the young disperse short distances to build burrows of their own, tiny versions of the adult’s.

When ready, young Kangaroo Island Micro-trapdoor spiders build their own burrows not far from their mothers’.
Jess Marsh, Author provided

Assessing the damage

My colleagues and I are in this conservation park today to locate patches of less fiercely burnt land in which to look for survivors. Sadly, all the known western populations of this enigmatic spider were destroyed. I am yet to find any survivors in the fire ground, but it is early days.

We will be out here for the next year or so, walking hundreds of kilometres of creek lines, searching for signs of life. There is a lot of land out there. Around 210,000 hectares was burnt, almost half of Kangaroo Island. I remain hopeful that some colonies have survived.

If we find some Kangaroo Island Micro-trapdoor spiders – what then?

Surviving the initial blaze is the first step in the struggle for survival. The post-fire environment has many threats – habitat loss, exposure to hungry predators, weeds. Today, I noticed areas where soil, loosened by fire, has washed into creeks, completely burying them.

If we find some surviving individuals, we’ll protect them by installing sediment control, removing weeds and monitoring them in future.

Why should we care?

Not everyone loves spiders. I get that. But the functions invertebrates perform are vital. Our ecosystem relies on them; humans rely on them. Yet collectively our understanding of invertebrates – their importance and their value – is dangerously low.

The Kangaroo Island Micro-trapdoor Spider plays its own role the ecosystem. It is a predator, but we don’t really know what it eats. It’s a food source for birds, mammals or reptiles, but we don’t know what eats it. So, why should we care?

Firstly, I firmly believe every species has its own intrinsic value; every extinction, although a natural part of life, is a loss.

Secondly, the ecosystem is so complicated we don’t know exactly how the loss of one species will impact its prey, the parasites that live on it or its predators. And when we’re facing multiple extinctions, these effects could be devastating.

The Kelly Hill Conservation Park in Kangaroo Island was badly burnt in last summer’s fires.
Jess Marsh, Author provided

The Kangaroo Island Micro-trapdoor spider, the Kangaroo Island Assassin Spider, the Green Carpenter Bee – we only know these species are threatened because scientists like me have spent years or decades studying them.

But the majority of Australia’s invertebrate species are yet to be discovered. Many will be similarly at risk, but we have no way of measuring the scale of risk or the repercussions. That’s a fact we should all find scary.

There is hope, though. It’s not yet over for these species. Work such as ours is a step towards understanding how worsening bushfires will affect these vital, but often forgotten, members of our ecosystem.




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Bushfires: can ecosystems recover from such dramatic losses of biodiversity?


The Conversation

Jess Marsh, Research fellow at the Harry Butler Institute, Murdoch University

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

I travelled Australia looking for peacock spiders, and collected 7 new species (and named one after the starry night sky)



Heath Warwick, Author provided

Joseph Schubert, Museums Victoria

After I found my first peacock spider in the wild in 2016, I was hooked. Three years later, I was travelling across Australia on a month-long expedition to document and name new species of peacock spiders.

Peacock spiders are a unique group of tiny, colourful, dancing spiders native to Australia. They’re roughly between 2.5 and 6 millimetres, depending on the species. Adult male peacock spiders are usually colourful, while female and juvenile peacock spiders are usually dull brown or grey.




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Like peacocks, the mature male peacock spiders display their vibrant colours in elegant courtship displays to impress females. They often elevate and wave their third pair of legs and lift their brilliantly coloured abdomens – like dancing.

Maratus laurenae. Male peacock spiders have brilliant colours on their abdomen to attract females.
Author provided

Up until 2011, there were only seven known species of them. But since then, the rate of scientific discovery has skyrocketed with upwards of 80 species being discovered in the last decade.

Thanks to my trip across Australia and the help from citizen scientists, I’ve recently scientifically described and named seven more species from Western Australia, South Australia and Victoria. This brings the total number of peacock spider species known to science up to 86.

Spider hunting: a game of luck

Citizen scientists – other peacock spider enthusiasts – shared photographs and locations of potentially undocumented species with me. I pulled these together to create a list of places in Australia to visit.

I usually find spider hunting to be a relaxing pastime, but this trip was incredibly stressful (albeit amazing).

The thing about peacock spiders is they’re mainly active during spring, which is when they breed. Colourful adult males are difficult – if not impossible – to find at other times of year, as they usually die shortly after the mating season. This meant I had a very short window to find what I needed to, or I had to wait another year.

Classic.

Even when they’re active, they can be difficult to come across unless weather conditions are ideal. Not too cold. Not too rainy. Not too hot. Not too sunny. Not too shady. Not too windy. As you can imagine, it’s largely a game of luck.

The wild west

I arrived in Perth, picked up my hire car and bought a foam mattress that fitted in the back of my car – my bed for half of the trip. I stocked up on tinned food, bread and water, and I headed north in search of these tiny eight-legged gems.

My first destination: Jurien Bay. I spent the whole day under the hot sun searching for a peculiar, scientifically unknown species that Western Australian photographer Su RamMohan had sent me photographs of. I was in the exact spot it had been photographed, but I just couldn’t find it!

I travelled across Denmark, Western Australia.
Author provided

The sun began to lower and I was using up precious time. I made what I now believe was the right decision and abandoned the Jurien Bay species for another time.

I spent days travelling between dramatic coastal landscapes, the rugged inland outback, and old, mysterious woodlands.

Kalbarri Gorge, Western Australia, where Maratus constellatus was found.
Author provided

I hunted tirelessly with my eyes fixed on the ground searching for movement. In a massive change of luck from the beginning of my trip, it seemed conditions were (mostly) on my side.

With the much-appreciated help of some of my field companions from the University of Hamburg and volunteers from the public, a total of five new species were discovered and scientifically named from Western Australia.

The Little Desert

Two days after returning from Western Australia, I headed to the Little Desert National Park in Victoria on a Bush Blitz expedition, joined by several of my colleagues from Museums Victoria.

I’d thought the landscape’s harsh, dry conditions were unsuitable for peacock spiders, as most described species are known to live in temperate regions.

Capturing spiders in a bug net.
Heath Warwick, Author provided

To my surprise, we found a massive diversity of them, including two species with a bigger range than we thought, and the discovery of another species unknown to science.

This is the first time two known species – Maratus robinsoni and Maratus vultus – had been found in Victoria. Previously, they had only been known to live in eastern New South Wales and southern Western Australia respectively.




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Our findings suggest other known species may have much bigger geographic ranges than we previously thought, and may occur in a much larger variety of habitats.

And our discovery of the unknown species (Maratus inaquosus), along with another collected by another wildlife photographer Nick Volpe from South Australia (Maratus volpei) brought the tally of discoveries to seven.

What’s in a name?

Writing scientific descriptions, documenting, and naming species is a crucial part in conserving our wildlife.




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With global extinction rates at an unprecedented high, species conservation is more important than ever. But the only way we can know if we’re losing species is to show and understand they exist in the first place.


  • Maratus azureus: “Deep blue” in Latin, referring to the colour of the male.
Maratus azureus.
Author provided
  • Maratus constellatus: “Starry” in Latin, referring to the markings on the male’s abdomen which look like a starry night sky.
Maratus constellatus.
Author provided
  • Maratus inaquosus: “Dry” or “arid” in Latin, for the dry landscape in Little Desert National Park this species was found in.
Maratus inaquosus
Author provided
  • Maratus laurenae: Named in honour of my partner, Lauren Marcianti, who has supported my research with enthusiasm over the past few years.
Maratus laurenae
Author provided
  • Maratus noggerup: Named after the location where this species was found: Noggerup, Western Australia.
Maratus noggerup
Author provided
  • Maratus suae: Named in honour of photographer Su RamMohan who discovered this species and provided useful information about their locations in Western Australia.
Maratus suae
Author provided
  • Maratus volpei: Named in honour of photographer Nick Volpe who discovered and collected specimens of this species to be examined in my paper.
Maratus volpei
Nick Volpe, Author provided

These names allow us to communicate important information about these animals to other scientists, as well as to build legislation around them in the case there are risks to their conservation status.

I plan on visiting some more remote parts of Australia in hopes of finding more new peacock spider species. I strongly suspect there’s more work to be done, and more peacock spiders to discover.The Conversation

Joseph Schubert, Entomology/Arachnology Registration Officer, Museums Victoria

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

Don’t like spiders? Here are 10 reasons to change your mind



Hostile reactions to spiders are harming conservation efforts.
Karim Rezk/Flickr

Leanda Denise Mason, Curtin University

Australia is famous for its supposedly scary spiders. While the sight of a spider may cause some people to shudder, they are a vital part of nature. Hostile reactions are harming conservation efforts – especially when people kill spiders unnecessarily.

Populations of many invertebrate species, including certain spiders, are highly vulnerable. Some species have become extinct due to habitat loss and degradation.




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In dramatic efforts to avoid or kill a spider, people have reportedly crashed their cars, set a house on fire, and even caused such a commotion that police showed up.

A pathological fear of spiders, known as arachnophobia, is of course, a legitimate condition. But in reality, we have little to fear. Read on to find out why you should love, not loathe, our eight-legged arachnid friends.

A male peacock spider. Spiders are a vital part of nature.
She’s Got Legs/Caitlin Henderson

1. Spiders haven’t killed anyone in Australia for 40 years

The last confirmed fatal spider bite in Australia occurred in 1979.

Only a few species have venom that can kill humans: some mouse spiders (Missulena species), Sydney Funnel-webs (Atrax species) and some of their close relatives. Antivenom for redbacks (Latrodectus hasseltii) was introduced in 1956, and for funnel-webs in 1980. However, redback venom is no longer considered life-threatening.

2. Spiders save us from the world’s deadliest animal

Spiders mostly eat insects, which helps control their populations. Their webs – especially big, intricate ones like our orb weavers’ – are particularly adept at catching small flying insects such as mosquitos. Worldwide, mosquito-borne viruses kill more humans than any other animal.

3. They can live to an impressive age

The world’s oldest recorded spider was a 43- year-old female trapdoor spider (Gaius villosus) that lived near Perth, Western Australia. Tragically a wasp sting, not old age, killed her.

4. Spider silk is amazing

Spider silk is the strongest, most flexible natural biomaterial known to man. It has historically been used to make bandages, and UK researchers have worked out how to load silk bandages with antibiotics. Webs of the golden orb spider, common throughout Australia, are strong enough to catch bats and birds, and a cloak was once woven entirely from their silk.

Golden orb weaver (Trichonephila edulis)
Caitlin Henderson/She’s Got Legs

5. Their venom could save our life

The University of Queensland is using spider venom to develop non-addictive pain-killers. The venom rapidly immobilises prey by targeting its nervous system – an ability that can act as a painkiller in humans.




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The venom from a Fraser Island funnel web contains a molecule that delays the effects of stroke on the brain. Researchers are investigating whether it could be administered by paramedics to protect a stroke victim on the way to hospital.

Funnel-web venom is also being used to create targeted pesticides which are harmless to birds and mammals.

6. They could compete at Little Athletics

The Australian huntsman (Family Sparassidae) can run 40 body lengths per second, about eight times faster than the fastest human runners.

Other spiders have great throwing skills. To catch moths, the bolas spider spins a thread with a sticky glob of silk on the end. The glob mimics the scent of a female moth. When a male moth comes to investigate, the spider throws the glob at the moth, catches it then reels it in.

7. Spiders want to be left alone

Spiders are not aggressive and will either try to run away from people, or defend themselves. Many are exceptional at hiding or camouflaging themselves, in the hope we don’t even see them.

Wrap-around spiders (Dolophones species) flatten themselves around branches to hide during the day, then come out to build webs at night.

A wrap-around spider (Dolophones species) is a master of camouflage.
Caitlin Henderson/She’s Got Legs

Bird-dropping spiders hide by looking like, yes, bird-droppings.

The Western Australian shield-back trapdoor spiders (Idiosoma species) uses its unusually hard abdomen to “plug” its tunnel when a predator enters, creating an impenetrable shield.

Trapdoor spiders live in burrows with a silken lid that shuts tight, then gets covered in dirt or leaf litter.

Trapdoor burrows of an Idiosoma species open (left) and closed (right)
Author provided

8. Spiders have very unusual sex lives

It’s well known that some female spiders eat their partners during or after sex. But male Tasmanian cave spiders have evolved to avoid this fate. They use kinks in their legs to pin the female’s fangs apart while they mate, which can prevent her from killing him. These spiders are so fascinating, they are the subject of a documentary, Sixteen Legs

More generally, male spiders use their “hands” (called pedipalps), to transfer sperm into female spider “vaginas” (called epigynes).

During courtship, Australian male peacock spiders display their colourful abdomen to the female by using some pretty impressive dance moves.

9. Spiders are great mothers

Some female spiders produce milk for their young, or even sacrifice themselves as food. All spider mothers protect their babies, called spiderlings. However trapdoor spider mothers allow spiderlings to live in the home burrow for nine months, before they dig their own burrows nearby.

A wolf spider carrying her spiderlings.
She’s Got Legs/Caitlin Henderson

10. Humans need spiders to survive

It is important to remember that spiders and other invertebrates – animals without spines – make up 98% of animal species. They are vital to the functioning of ecosystems; without them, the remaining 2% of vertebrates, including humans, could not survive.

OK, OK. I care about spiders. Now what?

Spread the word to your friends and family that spiders should be cared for.

By all means, teach children that certain spiders require caution, and should be admired from a safe distance. But if your child has an irrational fear of spiders, address this as early as possible. Encourage positive interest in the spider world by exposing children to books and movies with spiders as the lead protagonists, such as Charlotte’s Web and Spiderman.

Research has shown that adults can overcome fear of spiders through frequent exposure. So be sure to share images of spiders with your arachnaphobic friends!

Caitlin Henderson contributed to this article.




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The Conversation


Leanda Denise Mason, Associate Lecturer, Curtin University

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

Curious Kids: why do spiders need so many eyes but we only need two?



Jumping spiders, like this one, usually have eight eyes: two very large front eyes to get a clear, colour image and judge distance, and extra side eyes to detect when something is moving.
Flickr/Thomas Shahan, CC BY-NC-ND

Samantha Nixon, The University of Queensland and Andrew Walker, The University of Queensland

Curious Kids is a series for children. If you have a question you’d like an expert to answer, send it to curiouskids@theconversation.edu.au You might also like the podcast Imagine This, a co-production between ABC KIDS listen and The Conversation, based on Curious Kids.


Can you find out why spiders need six eyes but we only need two? – Amos, age 3, Newcastle.


Hi, Amos. Thanks for your excellent question.

The first thing we should say is that while it’s true that some spiders have six eyes, most actually have eight.

The short answer to your question is that animals have evolved different eyes that best suit the lives they lead.




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Humans have two eyes that face forward. Our eyes are very good at seeing colours and shapes. Having two big eyes in the front of our head means they can work together to guess how far away something is (we call this “judging distance”). That makes it easier for us to catch another animal so we can eat it.

Spiders are also hunters and they need eyes that help them find and catch their food. In fact, most spiders can’t see very well, and use touch and taste to explore the world. But the kind of eyes they have tells us something about the food they eat and the lives they live.

Spider eyes for spider lives

Jumping spiders are active hunters, like tiny lions chasing down their prey (bugs). They usually have eight eyes: two very large front eyes to get a clear, colour image and judge distance, and extra side eyes to detect when something is moving. Here’s a picture of an Australian jumping spider.

Jumping spiders need two big eyes on the front so they can guess how far away their prey is.
Michael Duncan., Author provided

Some spiders make nets to catch their prey. These net-casting spiders also need to see clearly and judge distances. Some have developed huge, scary-looking black eyes that stare straight ahead, so they are nicknamed ogre spiders! These gigantic eyes help the spider to see a wide area and accurately throw down its spider web net to catch its prey. Here’s a picture of a net-casting spider.

This net-casting spider is from the Deinopis family. The little dots that look like nostrils are actually eyes!
Michael Duncan, Author provided

Some spiders live in caves that are completely dark, where eyes are no use at all. They have to rely on other senses to find their food in the dark. To save energy making eyes, these spiders lost their eyes during evolution, so now some of them have no eyes at all. You can see a picture of a spider like that here.

So why did most spiders end up with so many eyes?

Both human and spider eyes are the result of slowly evolving to help us survive in our different environments. One reason our human eyes are different from spiders is because our bodies and brains are also built differently.

For example, spiders don’t have necks. So they can’t turn their heads to look at things like we can. Having extra eyes around their heads is one way that spiders see more of the world around them, helping them to quickly spot prey or a potential predator.

Human eyes and spider eyes also do different jobs. Our two eyes are very complex and are good at doing many jobs at once, while spiders have different sorts of eyes that do different jobs.

For example, the large central eyes of jumping spiders are best for seeing shapes, but the simple side eyes have the important job of watching out for predators.

So a two-eyed spider or even an eight-eyed human isn’t impossible. But the two eyes we have and the eight eyes most spiders have are perfectly suited to help each of us live our lives just the way they are.




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Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to curiouskids@theconversation.edu.au


CC BY-ND

Please tell us your name, age and which city you live in. We won’t be able to answer every question but we will do our best.The Conversation

Samantha Nixon, PhD, The University of Queensland and Andrew Walker, Postdoctoral Research Fellow, The University of Queensland

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

Trapdoor spider species that stay local put themselves at risk



File 20190405 123397 omwexr.jpg?ixlib=rb 1.1
A palisade trapdoor spider of the new species E. turrificus walks across the rainforest floor near Maleny, Queensland.
Jeremy Wilson, Author provided

Jeremy Dean Wilson, Griffith University

Several new species of trapdoor spiders found in Queensland are finally described in an article published this month in Invertebrate Systematics.

But each of the new species occurs in only its own single, isolated patch of rainforest in southeastern Queensland, and nowhere else.

Because these species have such tiny natural distributions, they are especially vulnerable to extinction.




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Unique spider burrows

These newly described spiders have been given the common name palisade trapdoor spiders because of the strange and unique burrows they construct. The entrance to the burrow projects out from the surrounding soil like a miniature turret.

The remarkable palisade burrows constructed by two different species of palisade trapdoor spider. The burrow entrances project from the surrounding soil.
Jeremy Wilson (left), Michael Rix (right)

Not only that, but each of the four new palisade trapdoor spider species constructs its own unique type of burrow.

One species, found in national parkland near Gympie and known scientifically as Euoplos crenatus, constructs a particularly elaborate burrow. The hinged door that covers the burrow entrance is adorned with several rounded lobes which project from the door’s circumference.

This marvel of natural architecture is constructed by the spider using silk and soil. No other spider species in the world constructs something similar.

This species was originally discovered by local naturalists Kelvin and Amelia Nielsen in 1999, who then guided researchers back to the discovery location in 2016 to collect specimens so the species could be formally named.

The burrow entrance of Euoplos crenatus, with its peculiar ‘crenate’ burrow door.
Michael Rix

Another species, Euoplos thynnearum, constructs a burrow entrance with a thick lip within which the burrow door sits. It’s found in the Mary Cairncross Scenic Reserve, a 55-hectare patch of subtropical rainforest popular with visitors to the Sunshine Coast hinterland.

This species is named after Elizabeth, Mabel and Mary Thynne, who originally donated the reserve land to the local council in 1941 to honour their mother Mary Thynne (née Cairncross). Currently, this species is known to occur only within the reserve and in other rainforest patches in the immediate vicinity.

Burrow entrances of the new palisade trapdoor spider species Euoplos thynnearum. This species is largely restricted to a single rainforest patch, occurring within Mary Cairncross Scenic Reserve near Maleny.
Michael Rix

Short-range species at risk

Species that only only occur in a very small area, like these new palisade trapdoor spider species, are known as short-range endemic species.

Although scientists are naming new species at a faster rate than ever before, estimates of the total number of species on Earth still suggest that most animal species have not been formally named. With so much work still to do, some scientists have chosen to prioritise work on particular types of animals that are especially vulnerable to extinction.

In 2002, Mark Harvey, an arachnologist from the Western Australian Museum, proposed that scientists should prioritise the discovery and description of short-range endemic species.

He reasoned that the small ranges of these species make them inherently vulnerable to extinction, and that identifying, naming and studying them is the first step to protecting them.

The strange burrows of the trapdoor spider species Euoplos crenatus project out from between the roots and leaf-litter on the bank of a creek in a rainforest patch near Gympie, Queensland.
Jeremy Wilson

Staying local

For trapdoor spiders, short-range endemism is the rule, not the exception. These spiders live their entire lives in a burrow. Juvenile spiders walk only short distances from their mother’s burrow, before constructing a burrow of their own.

Usually, these spiders will then remain in the same burrow for the remainder of their lives, enlarging it as they grow.

Examples of different trapdoor spider species from eastern Australia. Top left, Arbanitis longipes; top right, Heteromigas sp.; bottom left, Cataxia sp.; bottom right, Namea sp.
Jeremy Wilson

Adult male trapdoor spiders will also leave their burrow to breed, but will only travel relatively short distances. Over time, this extremely limited dispersal ability has led to the evolution of many different trapdoor spider species, each of which occurs in only a very small area.

Since 2012, a research team, led by Queensland Museum researcher Michael Rix, has been trying to discover and name all species of spiny trapdoor spider – this group includes the palisade trapdoor spiders, as well as other strange trapdoor spider species such as the shield-backed trapdoor spiders of Western Australia.

A shield-backed trapdoor spider from Western Australia, showing the distinctive hardened disk on its abdomen which the spider uses to ‘plug’ its burrow as a protection from predators.
Mark Harvey

So far, this project has led to the description of more than 100 new species from throughout Australia, some of which are already classified as threatened by federal and state governments.




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The most iconic of these is Idiosoma nigrum (also a shield-backed trapdoor spider), which is a listed threatened species.

The discovery of all these weird and wonderful spider species should remind us that Australia has some of the most remarkable invertebrate species in the world, and new species are waiting to be discovered in the national parks and reserves which occur around, and even within, our towns and cities – under our noses.

Next time you visit a national park, or drive past a patch of forest while commuting along Australia’s east coast, think to yourself, what might be living in there? Do those species occur anywhere else? And above all, if we lose that forest remnant, what unique species might disappear along with it?The Conversation

Jeremy Dean Wilson, Ph.D candidate, Department of Environment & Science, Griffith University, Griffith University

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

Climate change is killing off Earth’s little creatures



File 20190116 152983 bx2j9j.jpg?ixlib=rb 1.1
A jumping spider, which uses sharp eyesight to hunt its prey.
ThomasShahan.com/Flickr, CC BY-SA

Bill Laurance, James Cook University

Climate change gets blamed for a lot of things these days: inundating small islands, fueling catastrophic fires, amping-up hurricanes and smashing Arctic sea ice.

But a global review of insect research has found another casualty: 40% of insect species are declining and a third are endangered. It confirms what many have been suspecting: in Australia and around the world, arthropods – which include insects, spiders, centipedes and the like — appear to be in trouble.




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The global review comes hard on the heels of research published in the Proceedings of the National Academy of Sciences USA that suggests a potent link between intensifying heat waves and stunning declines in the abundance of arthropods.

If that study’s findings are broadly valid – something still far from certain – it has chilling implications for global biodiversity.

Our natural world depends on arthropods.
Steve Raubenstine/Pixabay

Arthropod Armageddon

In the mid-1970s, researchers on the Caribbean island of Puerto Rico conducted a large-scale study to measure the total biomass (living mass) of insects and other arthropods in the island’s intact rainforests, using sweep nets and sticky-traps.

Four decades later, another research team returned to the island and repeated the study using identical methods and the same locations. To their surprise, they found that arthropod biomass was just one-eighth to one-sixtieth of that in the 1970s – a shocking collapse overall.

And the carnage didn’t end there. The team found that a bevy of arthropod-eating lizards, birds and frogs had fallen sharply in abundance as well.

Insects are crucial in food webs for species such as this hummingbird.
Pixabay

In the minds of many ecologists, a widespread collapse of arthropods could be downright apocalyptic. Arthropods pollinate some of our most important food crops and thousands of wild plant species, disperse seeds, recycle nutrients and form key links in food chains that sustain entire webs of life.

This ecological ubiquity arises because arthropods are so abundant and diverse, comprising at least two-thirds of all known species on Earth. In the 1940s, evolutionary biologist J. B. S. Haldane quipped that “God has an inordinate fondness for beetles.” Humans might think we rule the world, but the planet really belongs to arthropods.

Killer heat waves

The researchers who documented the arthropod collapse in Puerto Rico considered a variety of possible causes, including pesticides and habitat disruption. But the evidence kept pointing to another driver: rising temperatures.

Weather stations in Puerto Rico indicate that temperatures there have risen progressively in the past several decades – by 2℃ on average.

But the researchers are far less worried about a gradual increase in temperature than the intensification of heat waves—which have risen markedly in Puerto Rico. This is because nearly all living species have thresholds of temperature tolerance.

For example, research in Australia has shown that at 41℃, flying foxes become badly heat-stressed, struggling to find shade and flapping their wings desperately to stay cool.

But nudge the thermometer up just one more degree, to 42℃, and the bats suddenly die.

In November, heat waves that peaked above 42℃ in north Queensland killed off almost a third of the region’s Spectacled Flying Foxes. The ground beneath bat colonies was littered with tens of thousands of dead animals. Dedicated animal carers could only save a small fraction of the dying bats.

Bats die en-masse during a recent heatwave.

The El Niño connection

El Niño events – fluctuations in Pacific sea-surface temperatures that drive multi-year variations in weather across large swaths of the planet – are also part of this story. New research appears to be resolving longstanding uncertainties about El Niños and global warming.

Recent studies published in Nature and Geophysical Research Letters suggest global warming will in fact intensify El Niños – causing affected areas to suffer even more intensively from droughts and heat waves.

And this ties back to Puerto Rico, because the researchers there believe a series of unusually intense El Niño heatwaves were the cause the arthropod Armageddon. If they’re right then global warming was the gun, but El Niño pulled the trigger.

Beyond heat waves

Puerto Rico is certainly not the only place on Earth that has suffered severe declines in arthropods. Robust studies in Europe, North America, Australia and other locales have revealed big arthropod declines as well.

And while climatic factors have contributed to some of these declines, it’s clear that many other environmental changes, such as habitat disruption, pesticides, introduced pathogens and light pollution, are also taking heavy tolls.

Monarch butterflies are declining in the USA and Mexico, probably from habitat disruption.
Pixabay

So, at a planetary scale, arthropods are suffering from a wide variety of environmental insults. There’s no single reason why their populations are collapsing.




Read more:
Climate change: effect on sperm could hold key to species extinction


The bottom line is: we’re changing our world in many different ways at once. And the myriad little creatures that play so many critical roles in the fabric of life are struggling to survive the onslaught.The Conversation

Bill Laurance, Distinguished Research Professor and Australian Laureate, James Cook University

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

Australia: Large Number of New Spider Species Discovered in Queensland


The link below is to an article reporting on the discovery of over 50 new species of spider in Queensland, Australia.

For more visit:
https://www.theguardian.com/environment/2017/apr/11/fifty-new-species-of-spider-discovered-in-far-north-australia

The truth about spider bites in Australia – they’re unlikely to eat your flesh


Ronelle Welton, University of Melbourne and Bill Nimorakiotakis, Epworth Hospital

Recent news reports that a man had both his legs amputated after being bitten by a white-tailed spider have again cast this relatively harmless spider in a negative light. Experts have since said amputations may have been wrongly blamed on a spider bite, and authorities now consider a bacterial infection to be responsible for the man’s injuries. Despite this, the damage to the largely harmless white-tail may have been done. The Conversation

The venom from the white-tailed spider is listed as non-lethal.
It has not been shown to cause necrotic ulcers, which could result in the need for amputation. And there has never been any clear evidence necrotising arachnidism – the name give to a syndrome where the skin blisters and ulcerates following spider bites – has been seen in Australia.

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There is currently no clinical test to determine if you have been bitten by a spider. And there is no blood or swab test that can be performed to positively identify what spider it is if a bite is suspected. Whether it is a bite from a spider or another insect, the management is the same – most will get better without any medical treatment.

Spiders in Australia

The majority of spiders in Australia are voracious predators of insects. For the most part, they play a useful role in lowering insect numbers.

The venom transmitted through bites of some Australian spiders can cause harm to humans and even be life-threatening. The better known of these are the redback spider (Latrodectus hasselti), and the funnel-web spiders (genera Atrax and Hadronyche). Antivenom is available for both spiders.

Redback spider venom can cause a lot of pain. Advice would be to go to hospital if pain lasts for longer than a few hours and simple pain relief is not helping. Funnel-web spider venom can cause local swelling in addition to increasing heartbeat, salivation, muscle spasms and respiratory distress (trouble breathing).

Without appropriate first aid, quick access to hospital and antivenom, these bites can be lethal. For the “big black hairy” funnel-webs, appropriate first aid needs to be applied and it is advisable to call 000.

The redback spider is considered one of the most venomous to humans in Australia.
graibeard/Flickr, CC BY

Other spiders that have concerning bites include the trapdoor, whistling, sac, ground, orb and huntsman spiders. These may cause milder symptoms such as headache, swelling and pain, which does not last for a long time.

The white-tailed spider

White-tailed spiders (Lampona sp.) can be recognised by their cylindrical body shape and a white or grey spot on the end of their abdomen. They are found in eastern and most southern areas of Australia and New Zealand.

These spiders are active hunters, preying on other types of spiders and insects. They may transiently roam inside houses, especially in warmer weather, where they may be found in bedding or clothing that has been left on the floor.

One study of over 70 spider bite cases in which white-tailed spiders were identified showed patients experienced only a mild localised reaction, such as swelling, local pain or headache. To date clinical research has not been able to associate tissue loss with the venom of these spider bites.

Flesh-eating bacteria

The man at the centre of the recent story linking amputations to a white-tail spider bite was said to have a “flesh eating” infection. But there is a very low probability of an association between spiders and necrotisisng fasciitis (commonly known as flesh-eating disease).

Of course, any injury that causes a break in our skin leaves the capacity for bacteria to enter our body. Therefore be sure to keep an injury area clean. Questions have been raised as to the possibility of a spider introducing infections, but again, despite it being theoretically possible, it is unlikely.

Contributing factors to infection are if people have conditions such as diabetes or take medications, such as steroids like prednisolone, that lessen the body’s ability to fight infection.

How to prevent spider bite

  • Leave them alone
  • wear gloves if gardening
  • humanely remove spiders from your home and limit hiding spaces where possible inside the home
  • knock out shoes before putting them on; these are nice quiet homes for spiders.

For first aid after a spider bite, please see the Australian guidelines. Many bites don’t result in envenoming and death is very rare, so it is important to remain calm. But seek medical attention if there are concerning symptoms such as those described above: difficulty breathing, increased heartbeat and pain lasting longer than an hour.

Ronelle Welton, Scientist AVRU, University of Melbourne and Bill Nimorakiotakis, Associate Professor, Epworth Hospital

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