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.

Aussie scientists need your help keeping track of bees (please)



The Asian honey bee (Apis cerana) has been found in Cairns. It’s just one of the introduced bees buzzing under the radar.
Tobias Smith, Author provided

Manu Saunders, University of New England; Callum McKercher, University of New England; Mark Hall, Western Sydney University; Tanya Latty, University of Sydney, and Tobias Smith, The University of Queensland

Bees get a lot of good press. They pollinate our crops and in some cases, make delicious honey. But bees around the world face serious threats, and the public can help protect them.

Of more than 20,400 known bee species in the world, about 1,650 are native to Australia. But not all bees found in Australia are native. A few species have been introduced: some on purpose and others secretly hitchhiking, usually through international trade routes.

As bee researchers, we’ve all experienced seeing a beautiful, fuzzy striped bee buzzing about our gardens, only to realise it’s an exotic species far from home.




Read more:
The farmer wants a hive: inside the world of renting bees


We need the public’s help to identify the bees in Australian backyards. There’s a good chance some are not native, but are unwanted exotic species. Identifying new intruders before they become established will help protect our native species.

The European honey bee (Apis mellifera) fuels a valuable honey industry and contributes to agricultural pollination. Other introduced species are far less welcome.
Tobias Smith

Exotic bees in Australia

The European honey bee (Apis mellifera) is the best-known introduced species, first brought to Australia in the early 1800s. It is now well-established throughout the country, with profitable industries built around managed populations.

Other invasive species in Australia are less well known (or loved). The European bumblebee (Bombus terrestris) is present in high numbers in Tasmania, but isn’t thought to be established on mainland Australia.

This bumblebee has caused major harm to native bees in South America, competing for resources and spreading disease.

In northern Queensland, the Asian honey bee (Apis cerana) is established around Cairns and Mareeba, from a single incursion in 2007. The original founding colony is thought to have been a stowaway on a boat that sailed to Cairns from somewhere in southeast Asia or the Pacific, where this bee is widespread.

New Asian honey bee incursions at Australian ports occur almost annually, most recently in Townsville and Melbourne. But swift biosecurity responses have so far stopped them becoming established.

The European bumble bee (Bombus terrestris) lives in large numbers in Tasmania, but is not established on the mainland.
Tobias Smith, Author provided

Why should we care?

Most insects can spread and establish breeding populations before anyone notices them, so it’s important we pay attention to these small intruders.

Introduced species can bring new parasites or diseases into the country that may harm native insects – including our stingless bees that are so vital to crop pollination – or affect the valuable European honey bee industry.

While bumblebees may help commercial pollination in a handful of Australian crops, they and other introduced species can also compete with native species for resources, or spread weeds.

Most resources go to monitoring invasive species with a more dramatic and understood effect on agriculture and the environment. Bees sneak under the radar – but we’re still curious.

Take the African carder bee (Pseudoanthidium repetitum), which arrived in Australia in the early 2000s. Thanks to citizen scientists, we know they are spreading rapidly. In 2014, they were the third most common bee species found in a survey of Sydney community gardens.

An African carder bee spotted in Lismore. They are the third most common bee species in Sydney community gardens.
Tobias Smith, Author provided

Just recently, we found two invasive African carder bees in a backyard in Armidale in northern New South Wales while testing out a new insect monitoring method. There are no confirmed records of this invasive bee in Armidale, although we have seen a few around town since 2017.




Read more:
Bees: how important are they and what would happen if they went extinct?


Although it’s usually exciting to find a new record for a native species, finding an exotic bee where it’s not supposed to be is worrying. How long have they been there, and how many others are there?

The European bumble bee was recently sighted to global biodiversity.

You don’t have to be totally sure what kind of bee you’ve spotted. Just snap some pictures and upload it to a citizen scientist app like iNaturalist with the date and location.
Jean and Fred/Flickr, CC BY

Will you help us keep track?

Anyone can help keep track of potential new invasive species, simply by learning more about the insects in your local area and sharing observations on citizen science platforms such as iNaturalist, or through targeted projects like the African carder bee monitoring project.

You don’t need to be sure exactly what species you’ve seen. Uploading some clear, high-resolution photos, along with the date and location of your observation, will help naturalists and researchers identify it.




Read more:
Wasps, aphids and ants: the other honey makers


You can also participate in events such as the twice-yearly Wild Pollinator Count or local Bioblitzes.

Your efforts can help us detect emerging threats, and add to our records of both native and non-native bees (and other species). Plus it’s a great excuse to get outdoors and learn more about the insect life in your area.


This article was co-written with Karen Retra.The Conversation

Manu Saunders, Research fellow, University of New England; Callum McKercher, PhD Student, University of New England; Mark Hall, Research fellow, Western Sydney University; Tanya Latty, Associate professor, University of Sydney, and Tobias Smith, Ecologist, bee researcher and stingless bee keeper, The University of Queensland

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

Scientists fear insect populations are shrinking. Here are six ways to help


Scientists need your help to protect Australia’s insects and track their numbers.
Joe Castro/AAP

David Yeates, CSIRO; Katja Hogendoorn, University of Adelaide, and Manu Saunders, University of New England

Are you planning a big garden clean-up this summer, or stocking up on fly spray to keep bugs at bay? Before you do, it’s worth considering the damage you might cause to the insects we share the planet with.

Australia’s insect populations are under pressure. The problem is better known in the Northern Hemisphere, where over the past few years scientific studies have reported alarming declines in insect numbers.

We don’t yet have a true understanding of what is happening in Australia. This week, scientists gathered in Brisbane at the Australian Entomological Society conference to discuss the extent of the problem. Evidence suggests several species and populations are under threat.

Some might see insects as small and insignificant, but they perform functions crucial to sustaining life on Earth. There are several simple steps you can take to address insect decline in your area, or even help scientists keep tabs on the problem.

A gold wasp. Australian insect declines have not been well documented.
Oliver Niehuis/Australian Science Media Centre

We need to know more

In Australia, we know iconic species such as the bogong moth, green carpenter bee and Key’s matchstick grasshopper are in decline. There is documented evidence for the extinction of two Australian insect species, but this is probably just the tip of the iceberg.

A research review published this year suggested more than 40% of insect species globally are threatened with extinction over the next few decades. However, this estimate was based on limited studies of a few iconic insect groups in western Europe and the US.




Read more:
Scientists re-counted Australia’s extinct species, and the result is devastating


Such findings should be taken with caution. We do not have enough evidence to extrapolate to the whole planet.

Despite this, factors affecting insect populations overseas – such as habitat loss, climate change and insecticide use – most likely also apply in Australia. Bushfires and drought on this continent can also affect insect populations.

There are no published studies documenting insect decline in Australia, but anecdotal reports from entomologists suggest lower than average populations across a number of species. However, very few of our estimated 250,000 insect species are being formally monitored.

A Pelecorhynchid fly. Studies suggest insect populations are declining, but data in Australia is scarce.
CSIRO Entomology

Why you should care

Insects pollinate plants, dispose of waste and control pests, among other functions. The planet would cease to support life without the services insects provide.

If insect populations are in decline, so are the populations of larger animals such as birds and lizards that feed on them.




Read more:
You can help track 4 billion bogong moths with your smartphone – and save pygmy possums from extinction


In NSW, bogong moths are a staple food for mountain pygmy possums. A collapse in the moth population would lead to possums going hungry, which affects their breeding success.

Australia’s threatened species strategy prioritises action to protect 20 bird species – 14 of which feed partially or solely on insects.

Mountain pygmy possums feed on bogong moths.
Tim Bawden

Six ways to help insects

Insects are small and can inhabit hidden places, so you may not realise how many exist around you. Here are a few ways to help prevent insect decline in your home and elsewhere:

Household insecticide use can damage local insect populations.
Flickr

1. Entice insects to your garden: Lawn is a virtual desert for insects, so if you don’t really need it, cultivate insect-friendly native plants instead. Plan to have something flowering most of the year and aim for a variety of plant heights and structures, such as tall trees, thick shrubs and ground cover.

2. Put the fly spray away: Insecticides have become very efficient in recent years. They indiscriminately kill all insects, not just the ones you’re trying to get rid of. If you have to use insect spray, do so sparingly.

And whenever you can, choose food produced without lots of pesticides. These products are sold with labels such as organic, biodynamic, or chemical-free.

3. Turn off the lights: If you don’t need that outdoor light on all night, turn it off: the moths in your area will thank you. Many nocturnal insects can’t resist the light, but it disrupts their navigation system. This plays havoc with their ability to feed and reproduce.

4. Build them a home: Think about installing an insect hotel – a small structure of hollows for insects to rest and lay eggs in. Or simply leave dead wood or small areas of bare ground for insects to build nests in. If you don’t have a garden, join a local tree-planting group, or convince your council to plant more natives.

A flower fly. Scientists need help form the public to track insect numbers.
Denis Anderson/CSIRO



Read more:
How many species on Earth? Why that’s a simple question but hard to answer


5. Resist the urge to clean up: If there is a section of your garden, local park or nature strip that is unkempt, leave it that way. What looks untidy to you is a great place for insects to live.

6. Track insects on your smart phone: Scientists need help to better understand what is happening to our insects. Citizen science apps such as iNaturalist Australia, Wild Pollinator Count, the Atlas of Living Australia and Butterflies Australia help gather valuable information about insect biodiversity, so solutions can be targeted to problem areas.The Conversation

David Yeates, Director of the Australian National Insect Collection, CSIRO; Katja Hogendoorn, University of Adelaide, and Manu Saunders, Research fellow, University of New England

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