The cicada’s deafening shriek is the sound of summer, and humans have been drawn to it for thousands of years



Shutterstock

Eliza Middleton, University of Sydney and Linda Evans, Macquarie University

Around Australia, the buzz-saw siren of cicadas heralds the beginning of summer. With 237 recorded species of cicada in Australia, almost no area of the country is untouched by their song. Up to 800 species in Australia are still to be scientifically recognised.

Cicadas, however, aren’t unique to Australia: the insects are found all over the world, though they’re most common in tropical regions.

As the world’s loudest insects, the ear-splitting call from the males is a love song to draw their mates near. But humans, too, have been drawn to singing cicadas, with the insects featuring in ancient poetry and literature of different cultures for thousands of years.

So, as we settle into summer, let’s explore the curious life-cycle of cicadas, and how people in ancient Greece and China, in particular, revered them.

The sound of summer

The life of a cicada begins as one of up to 400 eggs laid by a female in the bark of a tree. A nymph (juvenile) cicada hatches, falls to the ground and tunnels into the dirt to begin the majority of its life.

Cicada nymphs will live in the soil for between one and five years, though different species may remain underground in the nymph stage for longer. In the US, for example, one species can live underground for up to 17 years before emerging.

When ready to become adults, nymphs must leave the soil to moult. A split opens along the back of the nymph’s exoskeleton and the adult cicada pushes its way out.

These cicada shells — the ghost of its youth — are often the only evidence we can find of the insect. As an adult, a cicada will eat, sing, mate and die, all in a few weeks.

A dry cicada shell clinging precariously to a post. The shell is fragile with a large split from the head down the back to the abdomen.
The shell left behind as a cicada changes from a nymph to an adult. You can see a large split from the head down the back to the abdomen the adult emerged from.
Eliza Middleton

Each species has its own unique call, and the noise can be truly deafening. For perspective, normal conversation between humans is recorded at about 60 decibels. But some cicada species, such as the Greengrocer cicada (Cyclochila australasiae) found along the coast of southeast Australia, can reach 120 decibels.

This is like standing beside emergency sirens. It’s also on the edge of causing pain or injury to human ears, which generally occurs at 130 decibels.

The noise is created by a structure called the tymbal, which works a bit like a drum. The tymbal is a thin membrane stretched across a number of “ribs” creating large chambers. These membranes vibrate rapidly through muscle action, which makes a clicking sound that’s amplified by their hollow abdomen.

After 17 years underground, cicada nymphs emerge in the billions | Planet Earth.

There are more than 3,200 cicada species scientifically described, and many more waiting to be discovered. They belong to the superfamily called the Cicadoidea, which is part of a larger animal group — the order Hemiptera, or the “true bugs”.

Insects in the Hemiptera order, such as aphids, leafhoppers and bed bugs, alongside cicadas, are known for having sucking and piercing mouthparts. This allows them to feed on sap by piercing the tree and drinking from the xylem (plant tissue that transports water and nutrients from roots to stems). This is how both the nymphs and adult cicadas feed — the former feeds off the roots while the latter feeds from the trunk.




Read more:
Photos from the field: zooming in on Australia’s hidden world of exquisite mites, snails and beetles


Symbolism and stories

For the people of ancient Greece and China, cicadas were the focus of many beliefs that, despite the separation of East from West, were surprisingly similar. Both cultures admired them.

For the Greeks, the “tettix” was carefree and harmless. For the Chinese, the “tchen” was noble, yet also humble.

A nymph cicada that just emerged from its shell, which lies beside it.
Shutterstock

Both societies loved the insects’ incessant call. Greek literature describes their call as “sweet”, such that a friendly cicada, legend says, once replaced the missing note when a string broke on a musician’s lyre. Like they do for us today, the cicadas’ hum also heralded the summer, especially the midday heat.

The Chinese of the Tang dynasty (618 to 906 AD) were so enamoured with the insects’ song, cicadas were caught and sold in small cages as pets. The Greeks may also have kept cicadas, as revealed by epitaphs written after their death, although the captive insects would have quickly died from starvation.

The esteem with which the cicada was held is also reflected in their association with the arts in both cultures.

They were the popular subject of Chinese poetry and paintings. And another Greek story tells us that when the Muses, goddesses of the arts, were born, an ancient race of men sang non-stop until they died, after which they transformed into cicadas.

Jade cicada
Jade cicada from the Han Dynasty, at the Xuzhou Museum.
Mary Harrsch/Wikimedia, CC BY-SA

Cicada biology was also noted in these ancient times. In the 4th century BC, Aristotle determined correctly that only the male cicada sings and the cicada’s call was produced by the movement of abdominal membranes. Chinese observers also noted the female’s lack of sound in the 6th century AD.

The insects’ life cycle was of enormous significance to both peoples. The nymphs’ emergence from the earth provided a powerful symbol of Greek “autochthony”, the belief a community had always lived in a particular place as the original inhabitants. And the moulted skin of adult cicadas was a sign of immortality.




Read more:
This ancient Chinese anatomical atlas changes what we know about acupuncture and medical history


What’s more, cicadas held similar ornamental values in both ancient China and Greece.

During China’s Han Dynasty (206 BC to 220 AD), jade cicadas were placed in the mouths of the dead. The stone had supposed preservative qualities, while the insect offered the hope of resurrection.

The Greek elite are said to have worn gold cicadas in their hair to signal their ties to Athens. Such ornamentation was also associated with Chinese nobility, in which golden cicadas adorned the hats of Han Dynasty court officials. Intriguingly, this practice was said to have been introduced by outsiders.

We cannot yet say whether such similar beliefs stem from early East-West contact. But the prominent cultural role of the “tchen” and “tettix” is certainly testimony to humanity’s enduring summer love affair with the curious caterwauling cicada.




Read more:
Want to teach kids about nature? Insects can help


The Conversation


Eliza Middleton, Invertebrate and behavioural ecology laboratory manager, University of Sydney and Linda Evans, Associate professor, Macquarie University

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

Photos from the field: zooming in on Australia’s hidden world of exquisite mites, snails and beetles



Dragon springtails (pictured) are widely distributed in forests of eastern Australia — yet they’re still largely unknown to science.
Nick Porch, Author provided

Nick Porch, Deakin University

Environmental scientists see flora, fauna and phenomena the rest of us rarely do. In this series, we’ve invited them to share their unique photos from the field.


Which animals are quintessentially Australian? Koalas and kangaroos, emus, tiger snakes and green tree frogs, echidnas and eastern rosellas, perhaps. And let’s not forget common wombats.

Inevitably, most lists will be biased to the more conspicuous mammals and birds, hold fewer reptiles and frogs, and likely lack invertebrates — animals without a backbone or bony skeleton — altogether.

I’m an invertophile, fascinated by our rich terrestrial invertebrate fauna, so my list will be different. I’m enchanted by stunning dragon springtails, by cryptic little Tasmanitachoides beetles, and by the poorly known allothyrid mites, among thousands of others.

Australia’s terrestrial invertebrate multitude contains several hundred thousand uniquely Australian organisms. Most remain poorly known.

To preserve our biodiversity, we first must ask: “which species live where?”. For our invertebrates, we are a long way from knowing even this.

The Black Summer toll

Last year, a team of scientists estimated that the Australian 2019-2020 bushfires killed, injured or displaced three billion animals. That was a lot. But it was also a woefully inadequate estimate, because it only accounted for mammals, reptiles, birds and frogs.

Hidden from view, many trillions more invertebrates burned or were displaced by the fires. And yes, invertebrates are animals too.

A mite from the family Bdellidae (on the right) has captured a springtail, and is using its piercing mouthparts to suck it dry. Mites and springtails are among the most abundant animals on the planet.
Nick Porch, Author provided

Admittedly, it’s hard to come to terms with invertebrates because they’re often hard to find and difficult to identify. Most species are inconspicuous, even if they belong to incredibly abundant groups, such as mites and springtails, which can occur in numbers exceeding 10,000 per square metre.

Most invertebrates are poorly known because there are so many species and so few people working on them. In fact, it’s likely only a quarter to one-third of Australia’s terrestrial invertebrate fauna is formally described (have a recognised scientific name).

A translucent land snail
Meredithina dandenongensis, a species from the wet forests of Victoria. It can be found during the day under rotting logs. The land snail family Charopidae contains hundreds of species across wetter parts of southern and eastern Australia.
Nick Porch, Author provided

One of the problems invertebrates have, in terms of attracting attention, is that many are not easily seen with the naked eye.

Macrophotography can magnify these wonders for a view into a world most of us are completely unfamiliar with. Even then, it often will be hard to know what we see. Everyone will recognise a kangaroo, but who can identify an allothyrid mite?

The photo below shows an undescribed species of mite from the family Allothyridae, from Mount Donna Buang in Victoria. The mite family Allothyridae has three described Australian species, and dozens more awaiting description.

An undescribed Allothyridae species. Just one of the many species in this group waiting to be studied.
Nick Porch, Author provided

This collage shows a selection of mites found in the forests of southeastern Australia. It’s likely many of the species shown here are unknown to science.

Mites are a very ancient and diverse group. They can be found abundantly in most terrestrial habitats but are rarely seen because most are several millimetres long or smaller.
Nick Porch, Author provided

A deeply ancient lineage

Animal ecologists, most of whom work on vertebrates, often joke that I “study the ‘food’, haha…”. They think they’re funny, but this reflects a deep seated bias — one extending from scientists to the wider public. This limits the development of a comprehensive understanding of biodiversity that has flow-on effects for conservation more broadly.

It’s true: invertebrates are food for larger animals. But their vital role in maintaining Australia’s ecosystems doesn’t end there.

Every species has an evolutionary history, a particular habitat, a set of behaviours reflecting that history, and a role to play in the ecosystem. And many terrestrial invertebrates belong to especially ancient lineages that record the deep history of Australia’s past.

The moss bug family Peloridiidae, for example, dates back more than 150 million years. For context, the kangaroo family (Macropodidae) is likely 15-25 million years old.

Their history is reflected in the breakup of the ancient supercontinent, Gondwana. In fact, Australian species of moss bugs are more closely related to South American species than to those from nearby New Zealand.

A bronze-coloured beetle with delicate, translucent wings
Chasoke belongs to the beetle family Staphylinidae, which is currently considered the largest family of organisms on Earth, with more than 60,000 scientifically described species. Mt. Donna Buang, Victoria.
Nick Porch, Author provided

This is a common pattern in terrestrial invertebrate groups. It reflects how the New Zealand plate separated from the remainder of Gondwana about 80 million years ago, while the Australian plate remained connected to South America via Antarctica.

Similar stories can be told from across the invertebrate spectrum. The photo below shows a few examples of these relics from Gondwana.

Peloridiid bugs — such as Hemiodoecus leai China, 1924 (top left) — are restricted to the wettest forests where they feed on moss. Top right: A new species of Acropsopilio (Acropsopilionidae) harvestman from the Dandenong Ranges. Bottom left: a new velvet worm from the Otway Ranges. Bottom right: Tasmanitachoides hobarti from Lake St Clair in central Tasmania.
Nick Porch, Author provided

Their fascinating evolution

Overprinting this deep history are the changes that occurred in Australia, especially the drying of the continent since the middle Miocene, about 12-16 million years ago.

This continent-wide drying fragmented wet forests that covered much of the continent, resulting in the restriction of many invertebrate groups to pockets of wetter habitat, especially along the Great Dividing Range and in southwestern Australia.




Read more:
Trapdoor spider species that stay local put themselves at risk


A consequence of this was the evolution in isolation of many “short-range endemic” species.

A short-range endemic species means their geographic distribution is less than 10,000 square kilometres. A short-range endemic mammal you might be familiar with is Leadbeater’s possum, restricted to the wet forests of the Victorian Central Highlands.

A long, brown and orange thrips with six legs.
This is Idolothrips spectrum, the largest thrips in the world. It’s called the giant thrips, even though it’s less than 10mm long. Dandenong Ranges, Victoria.
Nick Porch, Author provided

But short-range endemism is much more common in invertebrates than other organisms. This is because many invertebrates are poor dispersers: they don’t move between habitat patches easily. They may also maintain viable populations in small areas of suitable habitat, and are frequently adapted to very specific habitats.

Take Tropidotrechus, pictured below, a genus of beetles mostly restricted to the same region as Leadbeater’s possum. They, however, divide the landscape at a much finer scale because they’re restricted to deep leaf litter in cool, wet, forest gullies.

As Australia dried, populations of Tropidotrechus became isolated in small patches of upland habitat, evolving into at least seven species across the ranges to the east of Melbourne.

Tropidotrechus victoriae, Victoria’s unofficial beetle emblem (left). Related described and undescribed species are found in the nearby Central Highlands and South Gippsland ranges (right)
Nick Porch, Author provided

Discoveries waiting to happen

The trouble with knowing so little about Australia’s extraordinary number of tiny, often locally unique invertebrates, is that we then massively underestimate how many of them are under threat, or have been badly hit by events like the 2019-2020 fires.

If we wish to conserve biodiversity widely, rather than only the larger charismatic wildlife, then enhancing our knowledge of our short-range species should be a high priority.

One shiny green beetle on top of another
You don’t necessarily need specialist equipment to take pictures of our fascinating invertebrates. This is a phone picture of mating Repsimus scarab beetles (relatives to the Christmas beetles). It was taken at Bemboka in NSW, which burnt during the 2019-2020 fires.
Nick Porch, Author provided

We’ve only just scratched the surface of Australia’s wonderful invertebrate fauna, so there are enough discoveries for everyone.

You can join iNaturalist, a citizen science initiative that lets you upload images and identify your discoveries. Perhaps you’ll discover something new — and a scientist just might name it after you.




Read more:
Want to teach kids about nature? Insects can help


The Conversation


Nick Porch, Senior Lecturer in Environmental Earth Science, Deakin University

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

Bzzz, slap! How to treat insect bites (home remedies included)



Shutterstock

Cameron Webb, University of Sydney

It’s the holidays and we’re spending more time outdoors. This means we’re exposed to the more annoying and painful aspects of summer — insect bites and stings.

There are plenty of products at the local pharmacy to treat these. Some treat the initial bite or sting, others the itchy aftermath.

What about natural remedies? Few studies have actually examined them. But if they work for you, and don’t irritate already inflamed skin, there’s likely no harm in continuing.




Read more:
Buzz, buzz, slap! Why flies can be so annoying


Why do insects bite and sting?

When insects bite and sting, they are either defending themselves or need something from us (like blood).

Whatever the motivation, it can leave us with a painful or itchy reaction, sometimes a severe allergic reaction, or even a debilitating disease.

While insects sometimes get a bad rap, there are relatively few that actually pose a serious threat to our health.

Flies, mosquitoes

Many types of flies, especially mosquitoes, bite. In most instances, they need blood for nutrition or the development of eggs. The method of “biting” can vary between the different types of flies. While mosquitoes inject a needle-like tube to suck our blood, others chew or rasp away at our skin.

While researchers have studied what happens when mosquitoes bite, there is still much to learn about how to treat the bites.

So, avoiding mosquito bites is especially important given some can transmit pathogens that make us sick.




Read more:
Feel like you’re a mozzie magnet? It’s true – mosquitoes prefer to bite some people over others


We still have lots to learn about treating mosquito bites.
A/Prof Cameron Webb

Fleas, lice, mites and ticks

There are lots of other insects (such as bed bugs, fleas, lice) and other arthropods (such as mites, ticks) that bite.

But it is difficult to determine which insect has bitten us based on the bite reaction alone. This is generally because different people react in different ways to the saliva injected as they start to suck our blood.

Bees, wasps, ants

Then there are stinging insects, such as bees, wasps and ants. These are typically just defending themselves.

But as well as being painful, the venom they inject when they sting can cause potentially severe allergic reactions.

How do you best treat a sting or bite?

If you suffer potentially severe allergic reactions from bites or stings, immediately seek appropriate medical treatment. But for many other people, it is the initial painful reaction and itchy aftermath that require attention.

Despite how common insect bites can be, there is surprisingly little formal research into how best to treat them. Most of the research is focused on insect-borne diseases.

Even for recommended treatments, there is little evidence they actually work. Instead, recommendations are based on expert opinion and clinical experience.

For instance, heath authorities promote some general advice on treating insect bites and stings. This includes using pain relief medication (such as paracetamol or ibuprofen). They also advise applying a cold compress (such as a cold pack, ice, or damp cloth soaked in cold water) to the site of the sting or bite to help reduce the inflammation and to ease some of the discomfort.

Refreshing red drink in glass with ice cubes and lemon
Ice cubes aren’t just for summer cocktails. They can help reduce inflammation from insect bites and stings.
Shutterstock

There is also specific advice for dealing with stings and removing ticks.

However, if you do nothing, the discomfort of the bite or sting will eventually fade after a few days. The body quickly recovers, just as it would for a cut or bruise.

If you’re still in pain for more than a couple of days, or there are signs of an allergic reaction, seek medical assistance.

What about the itch?

Once the initial pain has started to fade, the itch starts. That’s because the body is reacting to the saliva injected when insects bite.

For many people, this is incredibly frustrating and it is all too easy to get trapped in a cycle of itching and scratching.

In some cases, medications, such as corticosteroid creams or antihistamines could help alleviate the itchiness. You can buy these from the pharmacy.

Then there’s calamine lotion, a mainstay in many Australian homes used to treat the itchiness caused by insect bites. But there are few studies that demonstrate it works.




Read more:
Are itchier insect bites more likely to make us sick?


Do any home remedies work?

If you’re looking for a home remedy to treat insect bites and the itchiness that comes with it, a quick internet search will keep you busy for days.

Potential home remedies include: tea bags, banana, tea tree or other essential oils, a paste of baking soda, vinegar, aloe vera, oatmeal, honey and even onion.

There is little evidence any of these work. But not many have actually been scientifically evaluated.

Tea tree oil is one of the few. While it is said to help treat skin reactions, the oil itself can cause skin reactions if not used as directed.

However, if a home remedy works for you, and it’s not causing additional irritation, there’s no harm in using it if you’re getting some relief.

With so much uncertainty about how to treat insect bites and stings, perhaps it is best if we avoid exposure in the first place. There are plenty of insect repellents available at your local pharmacy or supermarket that do this safely and effectively.The Conversation

Cameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of Sydney

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

Tiny treetop flowers foster incredible beetle biodiversity



Hundreds of beetle species seem to be specialists that feed only from small white flowers on trees.
Susan Kirmse, CC BY-ND

Caroline S. Chaboo, University of Nebraska-Lincoln

The Research Brief is a short take on interesting academic work.

The big idea

Biologists have long known that rainforest treetops support a huge number of beetle species, but why these canopies are so rich in beetle diversity has remained a mystery. New research by my colleague Susan Kirmse and me shows that flowering trees play a critical role in maintaining this diversity, and that beetles may be among the most diverse pollinators in the animal kingdom.

We carried out a one-year study in a remote part of the Amazon rainforest in Venezuela. We used a specially built crane to collect a total of 6,698 adult beetles representing 859 species. These were gathered from 45 individual trees of 23 different tree species.

We were surprised to discover that the majority of these beetles – 647, or 75.3% of species found – were living on flowering trees. In fact, 527 beetle species in 41 families were associated exclusively with flowers. Interestingly, the majority of these species – almost 60% – were exclusively found on trees that produce lots of small white flowers.

Overall, this discovery shows that flowering trees are likely among the most important drivers for maintaining the high diversity of beetles in rainforests. But this relationship goes both ways. Our study also suggests that beetles may be among the most underappreciated pollinators in tropical forests.

A tall metal structure emerging from the forest canopy in Venezuela.
Using a specialized crane, the team was able to collect beetles from the very top of the forest canopy.
Susan Kirmse, CC BY-ND

Why it matters

Tropical rainforests are the very heart of Earth’s biodiversity. They harbor about 65% to 75% of all terrestrial species, including the most tree species and the most insects.

After finding such a tight relationship between beetles and flowering trees, we wondered: How many beetle species could be involved in pollination in the Amazon? Our study found an average of 26.35 unique beetle species for every species of tree. With an estimated 16,000 Amazonian tree species, this suggests that there might be more species of flower-visiting beetles than any other insects on Earth, potentially surpassing by far the 20,000 species of bees and the 19,000 species of butterflies.

Our study shows that flowering tree species play an important role as diversity hotspots in tropical rainforest canopies. For policymakers and biologists hoping to preserve or restore rainforests, promoting the cultivation of trees and other plants – especially those with lots of small white flowers that beetles love – could help to maintain species-rich communities. Flowers are a very important resource, providing food and shelter for thousands of insects in addition to beetles. Thus, preserving plant diversity or selecting many different indigenous tree species for reforestation can enhance the diversity of insects.

An image of a iridescent green-blue beetle.
Beetles like the Griburius auricapillus are just some of the hundreds of species that can be found in treetops.
Susan Kirmse, CC BY-ND

What still isn’t known

Our research was the first to describe this tight relationship between beetles and rainforest trees, especially with trees that produce thousands of small, simple flowers. But how this association came to be is still unclear.

Many of the beetle species were found only on trees with this particular type of flower. The trees get an obvious benefit: pollination. But what specifically these trees offer to the beetles requires further study. The simpler flowers are easier for beetles to access, but is the appeal food, like petals, pollen or nectar? Or maybe a home to find mates or lay eggs for the young to grow?

[You’re smart and curious about the world. So are The Conversation’s authors and editors. You can get our highlights each weekend.]

What’s next

To fight the worldwide rapid declines in insect diversity, researchers and conservationists must understand the ecological connections between insects and their food plants. Long-term studies, particularly in research plots like the one we used in Venezuela, allow researchers to collect layers of information that help unravel the complexity of diversity.

Yet such sites rely on political interest and stability. Political instability in Venezuela is preventing our fieldwork from continuing at the Venezuela plot.

While we can’t return to our study site in Venezuela, it is clear that researchers must work together to understand the mysteries of life on Earth. But biologists are racing the clock as large rainforests are destroyed forever.The Conversation

Caroline S. Chaboo, Adjunct Professor in Insect Systematics, University of Nebraska-Lincoln

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

La Niña will give us a wet summer. That’s great weather for mozzies



Geoff Whalan/Flickr, CC BY-NC-ND

Cameron Webb, University of Sydney

The return of the La Niña weather pattern will see a wetter spring and summer in many parts of Australia.

We know mosquitoes need water to complete their life cycle. So does this mean Australia can expect a bumper mozzie season? How about a rise in mosquito-borne disease?

While we’ve seen more mosquitoes during past La Niña events, and we may well see more mosquitoes this year, this doesn’t necessarily mean we’ll see more related disease.

This depends on a range of other factors, including local wildlife, essential to the life cycle of disease-transmitting mosquitoes.

What is La Niña?

La Niña is a phase of the El Niño-Southern Oscillation, a pattern of ocean and atmospheric circulations over the Pacific Ocean.

While El Niño is generally associated with hot and dry conditions, La Niña is the opposite. La Niña brings slightly cooler but wetter conditions to many parts of Australia. During this phase, northern and eastern Australia are particularly likely to have a wetter spring and summer.

Australia’s most recent significant La Niña events were in 2010-11 and 2011-12.




Read more:
Explainer: El Niño and La Niña


Why is wet weather important for mosquitoes?

Mosquitoes lay their eggs on or around stagnant or still water. This could be water in ponds, backyard plant containers, clogged gutters, floodplains or wetlands. Mosquito larvae (or “wrigglers”) hatch and spend the next week or so in the water before emerging as adults and buzzing off to look for blood.

If the water dries up, they die. But the more rain we get, the more opportunities for mosquitoes to multiply.

Mosquito biting a person's hand
Mosquito populations often increase after wet weather.
Cameron Webb/Author provided

Mosquitoes are more than just a nuisance. When they bite, they can transmit viruses or bacteria into our blood to make us sick.

While Australia is free of major outbreaks of internationally significant diseases such as dengue or malaria, every year mosquitoes still cause debilitating diseases.

These include transmission of Ross River virus, Barmah Forest virus and the potentially fatal Murray Valley encephalitis virus.




Read more:
Explainer: what is Murray Valley encephalitis virus?


What happens when we get more rain?

We’ve know for a long time floods provide plenty of water to boost the abundance of mosquitoes. With more mosquitoes about, there is a higher risk of mosquito-borne disease.

The amount of rainfall each summer is also a key predictor for seasonal outbreaks of mosquito-borne disease, especially Ross River virus.




Read more:
Explainer: what is Ross River virus and how is it treated?


Inland regions of Queensland, New South Wales and Victoria, especially within the Murray Darling Basin, are particularly prone to “boom and bust” cycles of mosquitoes and mosquito-borne disease.

In these regions, the El Niño-Southern Oscillation is thought to play an important role in driving the risks of mosquito-borne disease.

The hot and dry conditions of El Niño aren’t typically ideal for mosquitoes.

But historically, major outbreaks of mosquito-borne disease have been associated with extensive inland flooding. This flooding is typically associated with prevailing La Niña conditions.

For instance, outbreaks of Murray Valley encephalitis in the 1950s and 1970s had significant impacts on human health and occurred at a time of moderate-to-strong La Niña events.




Read more:
Our new model shows Australia can expect 11 tropical cyclones this season


Over the past decade, when La Niña has brought above average rainfall and flooding, there have also been outbreaks of mosquito-borne disease.

These have included:

  • Victoria’s record breaking epidemic of Ross River virus in 2016-17 after extensive inland flooding

  • southeast Queensland’s outbreak of Ross River virus in 2014-15, partly attributed to an increase in mosquitoes associated with freshwater habitats after seasonal rainfall

  • eastern Australia’s major outbreaks of mosquito-borne disease associated with extensive flooding during two record breaking La Niñas between 2010 and 2012. These included Murray Valley encaphalitis and mosquito-borne illness in horses caused by the closely related West Nile virus (Kunjin strain).

We can’t say for certain there will be more disease

History and our understanding of mosquito biology means that with the prospect of more rain, we should expect more mosquitoes. But even when there are floods, predicting outbreaks of mosquito-borne disease isn’t always simple.

This is because of the role wildlife plays in the transmission cycles of Ross River virus and Murray Valley encephalitis virus.




Read more:
After the floods come the mosquitoes – but the disease risk is more difficult to predict


In these cases, mosquitoes don’t hatch out of the floodwaters carrying viruses, ready to bite humans. These mosquitoes first have to bite wildlife, which is where they pick up the virus. Then, they bite humans.

So how local animals, such as kangaroos, wallabies and water birds, respond to rainfall and flooding will play a role in determining the risk of mosquito-borne disease. In some cases, flooding of inland wetlands can see an explosion in local water bird populations.

How can we reduce the risks?

There isn’t much we can do to change the weather but we can take steps to reduce the impacts of mosquitoes.

Wearing insect repellent when outdoors will help reduce your chance of mosquito bites. But it’s also important to tip out, cover up, or throw away any water-holding containers in our backyard, at least once a week.

Local authorities in many parts of Australia also undertake surveillance of mosquitoes and mosquito-borne pathogens. This provides an early warning of the risk of mosquito-borne disease.




Read more:
The worst year for mosquitoes ever? Here’s how we find out


The Conversation


Cameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of Sydney

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

‘Jewel of nature’: scientists fight to save a glittering green bee after the summer fires



Remko Leijs, Author provided

Katja Hogendoorn, University of Adelaide; Remko Leijs, Flinders University, and Richard V Glatz, University of Adelaide

This article is a preview of Flora, Fauna, Fire, a multimedia project launching on Monday July 13. The project tracks the recovery of Australia’s native plants and animals after last summer’s bushfire tragedy. Sign up to The Conversation’s newsletter for updates.


The green carpenter bee (Xylocopa aerata) is an iconic, beautiful native species described as a “jewel of nature” for its metallic green and gold colouring. Carpenter bees are so named because they excavate their own nests in wood, as opposed to using existing holes.

With a body length of about 2 centimetres, it is among the largest native bees in southern Australia. While not used in honey farming, it is an important pollinator for several species of Australian native plants.

Last summer’s catastrophic bushfires significantly increased the risk of local extinctions of this magnificent species. We have studied the green carpenter bee for decades. For example, after the 2007 fires on Kangaroo Island, we bolstered the remaining population by providing nesting materials.

To see our efforts – and more importantly, most of the habitat these bees rely on – destroyed by the 2020 fire was utterly devastating.

Much of Kangaroo Island was incinerated by the summer bushfires.
Daniel Mariuz/AAP

A crucial pollinator on the brink

The green carpenter bee is a buzz-pollinating species. Buzz pollinators are specialist bees that vibrate the pollen out of the flowers of buzz-pollinated plants.

Many native plants, such as guinea flowers, velvet bushes, Senna, fringe, chocolate and flax lilies, rely completely on buzz-pollinating bees for seed production. Introduced honey bees do not pollinate these plants.




Read more:
Our field cameras melted in the bushfires. When we opened them, the results were startling


The green carpenter bee went extinct on mainland South Australia in 1906 and in Victoria in 1938. It still occurs on the relatively uncleared western half of Kangaroo Island in South Australia, in conservation areas around Sydney, and in the Great Dividing Range in New South Wales.

Local extinctions were probably due to habitat clearing and large, intense bushfires. The last time the green carpenter bee was seen in Victoria was early December 1938 in the Grampians, which burnt completely during the Black Friday fires of January 1939.

There are several reasons green carpenter bees are vulnerable to fire, including:

  • the species uses dead wood for nesting, which burns easily
  • if the nest burns before the offspring matures in late summer, the adult female might fly away but won’t live long enough to reproduce again, and
  • the bees need floral resources throughout the year.
A male green carpenter bee.
Remko Leijs, Author provided

Nowhere to nest

The bees mainly dig their nests in two types of soft wood: dry flowering stalks of grass trees and, crucially important, large dead Banksia trunks. The availability of both nesting materials is intricately connected with fire.

Green carpenter bees sometimes nest n the dried flowering stalks of grass trees, also known as Xanthorrhoea.
Remko Leijs, Author provided

Grass trees flower prolifically after fire, but the dry stalks are only abundant between two and five years after fire. Banksia species don’t survive fire, and need to grow for at least 30 years to become large enough for the bees to use.

Bees nesting in an artificial stalk.
Remko Leijs, Author provided

With increasingly frequent and intense fires, there’s not enough time for Banksia trunks to grow big enough, before they’re wiped out by the next fire.

A helping hand after the 2007 fires

In 2007, Flinders Chase National Park on Kangaroo Island burnt almost entirely.

An artificial stalk nesting site installed in a Xanthorrea.
Remko Leijs, Author provided

However, in long-unburnt areas adjacent to the park, carpenter bee nests were still present. From there, they colonised the many dry grass tree stalks that resulted from the fire in the park.

In 2012, most flowering stalks had decayed. In an attempt to bolster population size, we successfully developed artificial nesting stalks to tide the bees over until new Banksia, suitable for nesting, would become available.

Since then, each year we’ve placed artificial nesting stalks in fire-affected areas where the bee still occurred. Almost 300 female carpenter bees have successfully used our stalks to raise their offspring.

Then came the January 2020 fires

At the time of the 2020 fires on Kangaroo Island, there were more than 150 nests containing mature brood in the stalks we had provided.

We’d placed these in 12 sites in and around Flinders Chase National Park, to spread risk – to no avail, as they all burnt.

We were horrified to see the intensity and speed of the fire that turned our efforts to ash, along with most of the remnant, long (more than 60 years) unburnt Banksia habitat the bees rely on. In New South Wales, much of the species’ natural range was also burnt.

The yellow dots represent known green carpenter bee nests. In red: the area burnt in 2020. Only a subset of the remaining green and yellow patches still have the right vegetation for the green carpenter bee.
Nature Maps SA/Remko Leijs, Author provided

What’s next for the green carpenter bee?

To fully appreciate the impact, we need to survey the remaining long unburnt areas on Kangaroo Island and in NSW.

Encouragingly, we have already found a few natural nests on Kangaroo Island, but the remaining suitable areas are small and isolated, and densities are likely to be low.

With funds raised through the Australian Entomological Society and the Wheen Bee Foundation, and with help of the Kingscote Men’s Shed, we are making new nesting stalks.

The Kingscote Men’s Shed on Kangaroo Island is helping build new nesting stalks.
Remko Leijs, Author provided

With permission of landholders, we’ll place these new stalks in areas with good floral support, to enhance reproduction and help the bees disperse into conservation areas once suitable.

As we have learnt, success is not guaranteed. Extensive and repeated bush fires, combined with asset protection and fuel reduction burns, are making longtime unburnt habitat increasingly rare. It is this lack of old, continuous, unburnt forest that severely threatens the green carpenter bees’ existence.

The future of fire-vulnerable biodiversity

The carpenter bee is not the only species facing this problem. Many Australian plants and animals are not resilient to high frequency fires, no matter their intensity or time of year.

The ecological importance of longtime unburnt forest needs urgent recognition, as increased fire frequency – both of natural and “managed” fires – is likely to drive a suite of species to extinction.

For Kangaroo Island, this could include several small mammals, glossy black cockatoos, and a range of invertebrate species, including the green carpenter bees.

Given the expected increase in fire frequency and intensity associated with global heating, it’s time we recognise fire-vulnerable species as a category that requires urgent habitat protection.




Read more:
After last summer’s fires, the bell tolls for Australia’s endangered mountain bells


The Conversation


Katja Hogendoorn, University of Adelaide; Remko Leijs, Researcher, Flinders University, and Richard V Glatz, Associate research scientist, University of Adelaide

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

One, then some: how to count like a bee


Scarlett Howard, Deakin University and Adrian Dyer, RMIT University

If you were a honeybee, how would you choose where to find flowers? Imagine your first flight out of the hive searching for food. What would you do if you saw flower patches with one flower, or three, or twelve, or twenty?

Our new study, published in the Journal of Experimental Biology, tested honeybees on exactly this question. We wanted to understand how honeybees choose where to forage in environments like greenhouses where our food is pollinated, in local parks, or in our own backyards.

Specifically, our research looked at whether honeybees with no specific numerical training could choose a flower patch based on the quantity of flowers it had.

We found the bees could tell the difference between groups of 1 vs 4 flowers – but not between, say, 4 vs 5. Basically, they couldn’t differentiate between groups of 2 or more flowers.

A honeybee pollinating a strawberry plant flower in a greenhouse.
Adrian Dyer/RMIT University

A mathematical matter of life and death

The ability to tell the difference between two quantities can mean life or death for an animal. “Quantity discrimination” can be vital for survival in tasks including:

  • resource comparison: choosing a larger quantity of food

  • aggressive interactions: choosing to avoid conflicts with larger groups of individuals, and

  • avoiding predators: choosing to stay with a larger group of animals of the same species to reduce your chance of being eaten.

We are gaining a better understanding of quantity discrimination across the animal kingdom. Primates and other mammals, amphibians, reptiles, birds and fish all display some form of quantity discrimination in day-to-day tasks. For example, fish use quantity discrimination to stay in larger groups to reduce the chance of being eaten by a predator.

However, little is known about spontaneous number choices by insects.




Read more:
We taught bees a simple number language – and they got it


How do bees choose where to forage?

Honeybees assess the available flowers based on several factors, including scent, colour, shape and size.

Backyard flowers; which patch to choose if you were a bee?
Adrian Dyer/RMIT University

Honeybees typically visit around 150 individual flowers per flight from the hive to collect resources such as nectar or pollen. For a honeybee, a high quantity of flowers in a single area would mean less energy exertion than having to fly to many flower patches with less flowers.

Using different numbers of artificial flowers, we wanted to test whether individual honeybees could discriminate between a range of quantities, and how they might determine the quality of a flower patch.

Our honeybees were shown pairs of flower quantities ranging from easier number comparisons (such as 1 flower vs 12 flowers) to more challenging scenarios (such as 4 flowers vs 5 flowers).

The experimental set-up (left) and the quantity comparisons (right). Honeybees succeeded at spontaneously discriminating between 1 vs 12, 1 vs 4, and 1 vs 3 flowers, but no other comparisons. The honeybees were trained to associate single yellow dots with sugar water before being shown quantity comparisons.
Scarlett Howard

Interestingly, despite previous findings that trained honeybees can discriminate between challenging quantities and can also learn to add and subtract, the bees performed poorly in our spontaneous number task.

We found they were only able to discriminate between 1 vs 3, 1 vs 4, and 1 vs 12 flowers – wherein they preferred the larger quantity. When 1 flower was an option they succeeded, but confused any comparisons between groups of 2 flowers or more.

This result suggests flower patch choice based on numerical-type cues is difficult for honeybees. And this has implications for how flower displays are interpreted.

A honeybee flies towards three flowers.
Scarlett Howard

With today being World Bee Day, why not take the opportunity to discover what bees are doing in gardens near you. Chances are they’re going to any flower patch with more than one flower, rather than paying much attention to absolute numbers.




Read more:
Bees learn better when they can explore. Humans might work the same way


The Conversation


Scarlett Howard, Postdoctoral research fellow, Deakin University and Adrian Dyer, Associate Professor, RMIT University

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

How the humble dung beetle engineers better ecosystems in Australia


Paul Weston, Charles Sturt University and Theo Evans, University of Western Australia

Dung beetles play an important role helping clear up all the dung left by other animals in an environment.

In Australia there are approximately 475 native species of dung beetle.

But there’s a problem. Most of them are adapted to deal with marsupial dung. When British colonisers brought livestock down under, they introduced an entirely new type of dung that the native dung beetles were ill-equipped to handle.




Read more:
French beetles flown in to clean up Australia’s cattle dung


Not touching that dung

Cattle dung is wet and bulky. It is very unlike marsupial dung – which is typically small, dry pellets – and so the native dung beetles largely left it alone. As a result, large deposits of cattle dung accumulated in the Australian agricultural landscape.

Besides fouling the land, the dung was an excellent breeding site for bush flies and other nuisance insects, as well as internal parasites that plague the digestive tracts of livestock.

So CSIRO embarked on an ambitious plan to introduce into Australia many dung beetles that were adapted to livestock dung. Starting in 1966, it imported and released 43 species of dung beetles over 25 years.

The beetles came from places such as South Africa, France, Spain and Turkey. The chosen beetles had similar climate requirements and were adapted to wild and domestic livestock, so they could live in Australia and process livestock dung.

What do dung beetles do?

When people think of dung beetles, the popular image that comes to mind is that of an industrious beetle labouring to roll a large ball of dung across the landscape.

These little engineers are actually trying to find a suitable spot to situate the ball, on which they will lay an egg. Their offspring will have food and a safe place to grow up, and generate more dung beetles.

Most species of dung beetles actually tunnel beneath piles of dung and drag bits of it into subterranean chambers, where they then lay their eggs.

The larvae develop over the following weeks to months, eventually emerging as adults and crawling to the surface in search of a mate and another pile of dung to colonise.

The introduced dung beetles

Of the 43 species introduced to Australia by CSIRO, 23 have become established and many are having a positive impact.

The activities of dung beetles helped remove dung from pastures and with it, the breeding site for nuisance flies and internal parasites.

They also improved pasture fertility. They increased the permeability of pasture soils to rainwater which decreased runoff of rainwater laden with nutrients that can pollute waterways.

But it is not known just how widely each of the introduced species has spread. There might be geographical and seasonal gaps in dung beetle activity that could be filled by other species yet to be introduced to Australia.

Working with farming

Dung beetles have been around for tens of millions of years, but their ability to survive in modern agricultural environments may be jeopardised by some farming practices.

Tilling paddocks used in cropping and livestock rotation systems may destroy the developing dung beetle larvae.

Some deworming agents, used by livestock producers to control intestinal parasites, may pass through the livestock and out in their faeces, and might poison the dung beetles colonising the dung.

It should be possible to manage tillage and deworming to minimise harm to the dung beetles, and so maximise their positive impact on the land.




Read more:
Five things dung beetles do with a piece of poo


That’s where Dung Beetle Ecosystem Engineers (DBEE) comes in.

In this project, a group of research institutions, producer groups, land management groups and dung beetle entrepreneurs are working together.

The project, now in its second year, is supported by Meat and Livestock Australia and funded by the Rural Research and Development for Profit Program of the Australian Department of Agriculture, Water and the Environment. Charles Sturt University leads the project, with cooperators at CSIRO, University of Western Australia, University of New England, Mingenew-Irwin Group, Warren Catchment Council, Dung Beetle Solutions International, and LandCare Research NZ.

Dung Beetle Ecosystem Engineers aims to:

  1. understand the distribution of dung beetle species previously introduced to Australia, and predict their ultimate spread

  2. evaluate new species of dung beetle for importation and release into Australia

  3. estimate the economic impact of dung beetles on farming systems

  4. develop a database of information on dung beetles in Australasia and educational materials for use by a range of users

  5. work with farming and land management groups to engage landholders in detecting dung beetles and modifying agricultural practices to enhance the success of dung beetles.

At the end of the DBEE project, we will have a better understanding of the role of dung beetles as a farming tool, helping farmers choose agricultural practices that will improve their bottom line.

New dung beetle species will be ready to work for Australia and New Zealand, and a distribution network will enhance their spread to new geographic areas.

DBEE aims bring economic and ecological benefits to the agricultural sector and wider Australian and New Zealand community.The Conversation

Paul Weston, Senior Research Fellow / EH Graham Centre for Agricultural Innovation, Charles Sturt University and Theo Evans, Associate Professor , University of Western Australia

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

Australia’s bushfires could drive more than 700 animal species to extinction. Check the numbers for yourself



Invertebrates out greatly outnumber mammals everywhere, including in bushfire zones.
Michael Lee, CC BY-NC-ND

Mike Lee, Flinders University

The scale and speed of the current bushfire crisis has caught many people off-guard, including biodiversity scientists. People are scrambling to estimate the long-term effects. It is certain that many animal species will be pushed to the brink of extinction, but how many?

One recent article suggested 20 to 100, but this estimate mostly considers large, well-known species (especially mammals and birds).

A far greater number of smaller creatures such as insects, snails and worms will also be imperilled. They make up the bulk of biodiversity and are the little rivets holding ecosystems together.




Read more:
A season in hell: bushfires push at least 20 threatened species closer to extinction


But we have scant data on how many species of small creatures have been wiped out in the fires, and detailed surveys comparing populations before and after the fires will not be forthcoming. So how can we come to grips with this silent catastrophe?

This native bee (Amphylaeus morosus) has been devastated by the bushfires across much of its range. It plays important roles in pollinating plants and as part of the food web, but has no common name, and its plight is so far unheralded.
Reiner Richter https://www.ala.org.au/

Using the information that is available, I calculate that at least 700 animal species have had their populations decimated – and that’s only counting the insects.

This may sound like an implausibly large figure, but the calculation is a simple one. I’ll explain it below, and show you how to make your own extinction estimate with only a few clicks of a calculator.

Using insects to estimate true extinction numbers

More than three-quarters of the known animal species on Earth are insects. To get a handle on the true extent of animal extinctions, insects are a good place to start.

My estimate that 700 insect species are at critical risk involves extrapolating from the information we have about the catastrophic effect of the fires on mammals.

We can work this out using only two numbers: A, how many mammal species are being pushed towards extinction, and B, how many insect species there are for each mammal species.

To get a “best case” estimate, I use the most conservative estimates for A and B below, but jot down your own numbers.

How many mammals are critically affected?

A recent Time article lists four mammal species that will be severely impacted: the long-footed potoroo, the greater glider, the Kangaroo Island dunnart, and the black-tailed dusky antechinus. The eventual number could be much greater (e.g the Hastings River mouse, the silver-headed antechinus), but let’s use this most optimistic (lowest) figure (A = 4).

Make your own estimate of this number A. How many mammal species do you think would be pushed close to extinction by these bushfires?

We can expect that for every mammal species that is severely affected there will be a huge number of insect species that suffer a similar fate. To estimate exactly how many, we need an idea of insect biodiversity, relative to mammals.

How many insect species are out there, for each mammal species?

The world has around 1 million named insect species, and around 5,400 species of land mammals.

So there are at least 185 insect species for every single land mammal species (B = 185). If the current bushfires have burnt enough habitat to devastate 4 mammal species, they have probably taken out around 185 × 4 = 740 insect species in total. Along with many species of other invertebrates such as spiders, snails, and worms.

There are hundreds of insect species for every mammal species.
https://imgbin.com/

For your own value for B, use your preferred estimate for the number of insect species on earth and divide it by 5,400 (the number of land mammal species).

One recent study suggests there are at least 5.5 million species of insects, giving a value of B of around 1,000. But there is reason to suspect the real number could be much greater.




Read more:
The Earth’s biodiversity could be much greater than we thought


How do our estimates compare?

My “best case” values of A = 4 and B = 185 indicate at least 740 insect species alone are being imperilled by the bushfires. The total number of animal species impacted is obviously much bigger than insects alone.

Feel free to perform your own calculations. Derive your values for A and B as above. Your estimate for the number of insect species at grave risk of extinction is simply A × B.

Post your estimate and your values for A and B please (and how you got those numbers if you wish) in the Comments section and compare with others. We can then see what the wisdom of the crowd tells us about the likely number of affected species.




Read more:
How to unleash the wisdom of crowds


Why simplistic models can still be very useful

The above calculations are a hasty estimate of the magnitude of the current biodiversity crisis, done on the fly (figuratively and literally). Technically speaking, we are using mammals as surrogates or proxies for insects.

To improve these estimates in the near future, we can try to get more exact and realistic estimates of A and B.

Additionally, the model itself is very simplistic and can be refined. For example, if the average insect is more susceptible to fire than the average mammal, our extinction estimates need to be revised upwards.

Also, there might be an unusually high (or low) ratio of insect species compared to mammal species in fire-affected regions. Our model assumes these areas have the global average – whatever that value is!

And most obviously, we need to consider terrestrial life apart from insects – land snails, spiders, worms, and plants too – and add their numbers in our extinction tally.

Nevertheless, even though we know this model gives a huge underestimate, we can still use it to get an absolute lower limit on the magnitude of the unfolding biodiversity crisis.

This “best case” is still very sad. There is a strong argument that these unprecedented bushfires could cause one of biggest extinction events in the modern era. And these infernos will burn for a while longer yet.The Conversation

Mike Lee, Professor in Evolutionary Biology (jointly appointed with South Australian Museum), Flinders University

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

You can leave water out for wildlife without attracting mosquitoes, if you take a few precautions



Leaving water out for wildlife is important during droughts and bushfires but if it’s not changed regularly it can be a breeding ground for mosquitoes.
Roger Smith/Flickr, CC BY-NC

Cameron Webb, University of Sydney

Australia is in for a long, hot summer. The recent bushfires have been devastating for communities and wildlife. Drought is also impacting many regions.

Understandably, people want to leave water out for thirsty birds and animals.

Health authorities generally warn against collecting and storing water in backyards as one measure to protect against mosquito bites and mosquito-borne diseases caused by, for example, dengue and Ross River viruses.




Read more:
How Australian wildlife spread and suppress Ross River virus


But it’s possible to leave water out for wildlife – and save water for your garden – without supplying a breeding ground for mosquitoes, if you take a few precautions.

For some mozzies, any water will do

Mosquitoes often look for wetlands and ponds to lay their eggs. But sometimes, anything that holds water – a bucket, bird bath, drain or rainwater tank – will do.

When the immature stages of mosquitoes hatch out of those eggs, they wriggle about in the water for a week or so before emerging to fly off in search of blood.

While there are many mosquitoes found in wetlands and bushland areas, Aedes notoscriptus and Culex quinquefasciatus are the mosquitoes most commonly found in our backyards and have been shown to transmit pathogens that cause mosquito-borne disease.

The Australian backyard mosquito (Aedes notoscriptus) is quick to take advantage of water-filled containers around the home.
Cameron Webb (NSW Health Pathology)

In central and north Queensland, mosquitoes such as Aedes aegypti can bring more serious health threats, such as dengue, to some towns.




Read more:
After decades away, dengue returns to central Queensland


Mosquitoes can also impact our quality of life through bites as well as the nuisance of simply buzzing about our bedrooms and backyards.

So how can you stop mozzies making a home in your backyard?

Empty water containers once a week

Mosquitoes need access to standing water for about a week or so. Reduce the number of water-filled containers available or how long that water is available to mosquitoes.

Emptying a water-filled container once a week will stop the immature mosquitoes from completing their development and emerging as adults.

If you’re leaving water out for pets or wildlife, use smaller volume containers that will allow for easy emptying once a week. You can tip any remaining water into the garden, as mosquito larvae won’t survive if they’re “stranded” on soil.

For larger or heavier items, such as bird baths, flushing them out once a week with the hose will knock out most of the wrigglers and stop the mosquitoes completing their life cycle.

Make sure garden water doesn’t slosh about

Be careful with self-watering planter boxes. These often have a reservoir of water in their base and, while it may seem like a water-wise idea, these can turn into tiny mozzie hotels!

A simple trick to keep water available to plants, but not mosquitoes, is to fill your potted plant saucers with sand. The sand traps and stores some moisture but there is no water sloshing about for mosquitoes.

If you’re collecting water from showers, baths, or washing machines (commonly known as grey water), use it immediately on the garden, don’t store it outside in buckets or other containers.




Read more:
How drought is affecting water supply in Australia’s capital cities


Gutters, ponds, tanks and pools

Make sure your roof gutters and drains are free of leaves and other debris that will trap water and provide opportunities for mosquitoes.

Ensure rainwater tanks (and other large water-storage containers) are appropriately screened to prevent access by mosquitoes.

Rainwater tanks can be a useful way to conserve water in our cities but they can also be a source of mosquitoes.
Cameron Webb (NSW Health Pathology)

A well maintained swimming pool won’t be a source of mosquitoes. But if it’s turning “green”, through neglect and not intent, it may become a problem. Mosquitoes don’t like the chlorine or salt treatments typically used for swimming pools but when there is a build up of leaves and other detritus, as well as algae, the mosquitoes will move in.




Read more:
As heat strikes, here’s one way to help fight disease-carrying and nuisance mosquitoes


For backyard ponds, introducing native fish can help keep mosquito numbers down.

But if you want your pond to be a home for frogs, avoid fish as they may eat the tadpoles. Instead, try to encourage other wildlife that may help keep mosquito numbers down by creating habitats for spiders and other predatory insects, reptiles, frogs, birds, and bats.

Avoiding excessive use of insecticides around the backyard will help encourage and protect that wildlife too.

Mozzies can still come

There isn’t much that can be done about those mosquitoes flying in from over the back fences from local bushland or wetland areas.

Mosquitoes are generally most active at dusk and dawn so keep that in mind when planning time outdoors. But when mosquito populations are peaking, they’ll be active almost all day long.

Applying an insect repellent can be a safe and effective way to stop those bites.




Read more:
The best (and worst) ways to beat mosquito bites


Covering up with long pants, long-sleeved shirt and shoes will provide a physical barrier to mosquitoes. If you’re spending a lot of time outdoors, perhaps even consider treating your clothing with insecticide to add that extra little bit of protection.

Make sure insect screens are installed, and in good condition, on windows and doors. Mosquitoes outdoors can be bad; you don’t want them inside as well.The Conversation

Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of Sydney

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