Social distancing works – just ask lobsters, ants and vampire bats



Caribbean spiny lobsters normally live in groups, but healthy lobsters avoid members of their own species if they are infected with a deadly virus.
Humberto Ramirez/Getty Images

Dana Hawley, Virginia Tech and Julia Buck, University of North Carolina Wilmington

Social distancing to combat COVID-19 is profoundly impacting society, leaving many people wondering whether it will actually work. As disease ecologists, we know that nature has an answer.

Animals as diverse as monkeys, lobsters, insects and birds can detect and avoid sick members of their species. Why have so many types of animals evolved such sophisticated behaviors in response to disease? Because social distancing helps them survive.

In evolutionary terms, animals that effectively socially distance during an outbreak improve their chances of staying healthy and going on to produce more offspring, which also will socially distance when confronted with disease.

We study the diverse ways in which animals use behaviors to avoid infection, and why behaviors matter for disease spread. While animals have evolved a variety of behaviors that limit infection, the ubiquity of social distancing in group-living animals tells us that this strategy has been favored again and again in animals faced with high risk of contagious disease.

What can we learn about social distancing from other animals, and how are their actions like and unlike what humans are doing now?

Feed the sick, but protect the queen

Social insects are some of the most extreme practitioners of social distancing in nature. Many types of ants live in tight quarters with hundreds or even thousands of close relatives. Much like our day care centers, college dormitories and nursing homes, these colonies can create optimal conditions for spreading contagious diseases.

In response to this risk, ants have evolved the ability to socially distance. When a contagious disease sweeps through their society, both sick and healthy ants rapidly change their behavior in ways that slow disease transmission. Sick ants self-isolate, and healthy ants reduce their interaction with other ants when disease is present in the colony.

Healthy ants even “close rank” around the most vulnerable colony members – the queens and nurses – by keeping them isolated from the foragers that are most likely to introduce germs from outside. Overall, these measures are highly effective at limiting disease spread and keeping colony members alive.

Many other types of animals also choose exactly who to socially distance from, and conversely, when to put themselves at risk. For example, mandrills – a type of monkey – continue to care for sick family members even as they actively avoid sick individuals to whom they are not related. In an evolutionary sense, caring for a sick family member may allow an animal to pass on its genes through that family member’s offspring.

Mandrills live in large groups in the rainforests of equatorial Africa. They will often groom other group members, but actively avoid sick mandrills unless they are close family members.
Eric Kilby/Wikipedia, CC BY-SA

Further, some animals maintain essential social interactions in the face of sickness while foregoing less critical ones. For example, vampire bats continue to provide food for their sick groupmates, but avoid grooming them. This minimizes contagion risk while still preserving forms of social support that are most essential to keeping sick family members alive, such as food sharing.

These nuanced forms of social distancing minimize costs of disease while maintaining the benefits of social living. It should come as no surprise that evolution favors them in many types of animals.

Altruism makes us human

Human behavior in the presence of disease also bears the signature of evolution. This indicates that our hominid ancestors faced many of the same pressures from contagious disease that we are facing today.

Like social ants, we are protecting the most vulnerable members of our society from COVID-19 infection by ensuring that older individuals and those with pre-existing conditions stay away from potentially contagious people. Like monkeys and bats, we also practice nuanced social distancing, reducing non-essential social contacts while still providing essential care for sick family members.

A black garden ant queen (upper left), surrounded by adult ants, larvae (left), eggs (middle) and a cocoon (right).
Pan weterynarz/Wikipedia, CC BY-SA

There also are important differences. For example, in addition to caring for sick family members, humans sometimes increase their own risk by caring for unrelated individuals, such as friends and neighbors. And health care workers go further, actively seeking out and helping precisely those who many of us carefully avoid.

Altruism isn’t the only behavior that distinguishes human response to disease outbreaks. Other animals must rely on subtle cues to detect illness among group members, but we have cutting-edge technologies that make it possible to detect pathogens rapidly and then isolate and treat sick individuals. And humans can communicate health threats globally in an instant, which allows us to proactively institute behaviors that mitigate disease. That’s a huge evolutionary advantage.

Finally, thanks to virtual platforms, humans can maintain social connections without direct physical contact. This means that unlike other animals, we can practice physical rather than social distancing, which lets us preserve some of the important benefits of group living while minimizing disease risk.

Worth the disruption

The evidence from nature is clear: Social distancing is an effective tool for reducing disease spread. It is also a tool that can be implemented more rapidly and more universally than almost any other. Unlike vaccination and medication, behavioral changes don’t require development or testing.

However, social distancing can also incur significant and sometimes unsustainable costs. Some highly social animals, like banded mongooses, do not avoid group members even when they are visibly sick; the evolutionary costs of social distancing from their relatives may simply be too high. As we are currently experiencing, social distancing also imposes severe costs of many kinds in human societies, and these costs are often borne disproportionately by the most vulnerable people.

Given that social distancing can be costly, why do so many animals do it? In short, because behaviors that protect us from disease ultimately allow us to enjoy social living – a lifestyle that offers myriad benefits, but also carries risks. By implementing social distancing when it’s necessary, humans and other animals can continue to reap the diverse benefits of social living in the long term, while minimizing the costs of potentially deadly diseases when they arise.

Social distancing can be profoundly disruptive to our society, but it can also stop a disease outbreak in its tracks. Just ask ants.

[You need to understand the coronavirus pandemic, and we can help. Read The Conversation’s newsletter.]The Conversation

Dana Hawley, Professor of Biological Sciences, Virginia Tech and Julia Buck, Assistant Professor of Biology, University of North Carolina Wilmington

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

Coronavirus has finally made us recognise the illegal wildlife trade is a public health issue


Simon Evans, Anglia Ruskin University

There will be few positives to take from coronavirus. But the global pandemic may yet prove to be an important moment in the attempts to address the illegal wildlife trade.

The media has generally concentrated on effects rather than causes, in particular the global implications for public health and economies. But it is also vital to unravel the timeline of the pandemic and categorically determine its initial cause.

What we do know to date is that the epicentre of the disease was in the Chinese city of Wuhan, an important hub in the lucrative trade in wildlife – both legal and illegal. The outbreak is believed to have originated in a market in which a variety of animal-derived products and meats are widely available, including peacocks, porcupines, bats and rats. It’s also a market where regulatory and welfare standards are rudimentary at best.

Some of this trade is legal under Chinese domestic law but the existence of a parallel illegal trade – often within the very same market or stall – allows some traders to launder illicit wildlife products into the system. This situation is very difficult to regulate and control.

We are also reasonably certain that the spill-over event involved the crossover of the virus from animals to humans, similar to the situation with previous contagions like the Ebola and SARs viruses. In each of these cases, the existence of large, unsanitary and poorly-regulated wildlife markets provided an ideal environment for diseases to cross over between species. In a country like China, where wildlife consumption is
so deeply embedded in culture, such contamination can, and did, spread
rapidly.

The Chinese government has long advocated a “sustainable utilisation” approach to the country’s wildlife. It nonetheless responded to the current crisis by enacting a temporary ban on such markets, effectively closing down a significant sector of its domestic wildlife trade.

Biosecurity, public health and economic impact

In the longer term, the pandemic may provide the impetus to properly address the issue. This is because, while the illegal wildlife trade was once criticised almost purely in terms of conservation, it is now also being considered in relation to broader themes of biosecurity, public health and economic impact.

It is only in the wake of the COVID-19 outbreak that the full scale of China’s industry is emerging, with the temporary ban covering some 20,000 captive breeding enterprises and 54 different species allowed to be traded domestically. A report by the Chinese Academy of Engineering estimates the wildlife farming industry is worth around US$57 billion annually. These breeding centres are allowed to operate under loopholes in Chinese domestic law, arguably against the spirit of the Convention on International Trade in Endangered Species of Wild Fauna and Flora.

The parallel illegal trade is less easy to quantify, but globally it is valued by the UN at around US$23 billion. Given the resulting pandemic could cost as much as US$2.7 trillion, even on purely economic grounds there is a strong case for increased regulation.

There are compelling arguments for dismantling the trade anyway: animals are kept in abject conditions, and the trade hastens their demise in the wild. But in China the temporary ban remains just that – temporary. Critics argue that we have been there before with SARS and once the dust settled on that particular outbreak, China resumed business as usual.

What would seriously tackling the wildlife trade actually mean in practice? First, breeding centres for endangered species like tigers or pangolins would be permanently closed. This would make it much harder for their products to be laundered through legal channels and sold as more valuable “wild-caught”. Enforcement agencies currently need to monitor these centres closely to check against laundering, and shutting them down would free up resources to disrupt the supply of illegal products entering China from outside.

Such a move would also help reduce demand. Public education campaigns tell people about how the wildlife trade (both legal and illegal) harms endangered species, but the message is mixed: the presence of a parallel legal market still provides such products with legitimacy and sends a message that it is OK to purchase them, thereby increasing rather than decreasing demand.

In any case the new Chinese ban excludes products such as tiger bones that are used in traditional medicines. Some conservationists and activists are concerned that this exemption will lead to legalised trade under the assumption that better regulation will protect against future outbreaks. This argument is extremely difficult to validate and most conservationists continue to favour blanket trade bans.

Another worry is that, given humans have short memories, once the danger has passed public concern will turn to the next big problem. COVID-19 clearly represents an unparalleled opportunity to combat the wildlife trade, and ensure that animal-borne diseases do not mutate and cross over to humans. But only time will tell whether this opportunity will be taken or put off once again until the emergence of the next – perhaps even more virulent – pandemic poses an even graver global threat.The Conversation

Simon Evans, Principal Lecturer in Ecotourism, Anglia Ruskin University

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

Air-dropping poisoned meat to kill bush predators hasn’t worked in the past, and it’s unlikely to help now



Shutterstock

Justine M. Philip, Museums Victoria

After the summer’s devastating bushfires, the New South Wales government announced a plan to airdrop one million poisoned baits in the state’s most vulnerable regions over the next year. The plan is aimed at protecting surviving native animals from foxes, feral cats and wild dogs.

This isn’t the first time aerial baiting has been used in NSW recently. As the fire season got underway in September last year, the government’s biannual aerial baiting program scattered baits over nearly 8 million hectares in the Western Division alone – dispensing 43,442 aerial baits and 115,162 ground-laid baits over the drought-stricken region.

Biosecurity officers drying meat baits for the Autumn baiting program in Broken Hill last year.
NSW Government, Local Land Services, Western Region

In a study published this week, I explore Australia’s history as pioneers of this technology. The review raises serious concerns about the ethics and poor results of baiting programs, and the high uptake of baits by non-target species such as marsupials.

D-day for dingoes

Aerial baiting has been Australia’s foremost weapon against pest species for the past 74 years. The initial target was the dingo, to protect unguarded livestock from being killed.




Read more:
How Australia made poisoning animals normal


It started on Remembrance Day in 1946. Around 367,000 dry meat baits were airdropped across Queensland, each containing enough strychnine to kill an adult dingo. The campaign was considered a victory, despite only recovering one dingo carcass during the initial operation. Livestock predation apparently decreased; tracks in the sand vanished.

The following year, 1.5 million baits were distributed. Then in 1948 the quantity increased to 2.5 million baits across remote regions of Queensland and the Northern Territory.

Livestock predation decreased after airdropping baits, but at what cost?
CSIRO Science Image, CC BY

Thousands of baits to kill one dingo

The strychnine tablets took up to 12 tortuous hours for the poison to deliver its lethal kill. The baits used in research trials were still toxic after 14 weeks.

There was huge public criticism of the project at the time – much of it from graziers. They claimed ants and valuable pest-eating birds – magpies, small hawks, butcher birds, crows, ibis and curlew – were eating the baits.

In response, the Queensland government set up the first monitored trials. The 1954 report from the Chief Vermin Control Officer recorded:

In the dry season campaigns, the baits are dropped on water-holes, soaks, junctions of dried water courses, gorges in hills and all places where dogs must travel or gather in their search for water and game and in their movements with pups from the breeding areas.

The data recorded an average 14,941 baits dispensed for every dingo carcass recovered. Anecdotal evidence suggests the program was considered a success.

CSIRO research worker with young dingo, 1970.
National Archives of Australia

Then in 1968 – 21 years after aerial campaigns began – a four-year CSIRO study tested the effectiveness of aerial baiting. It found the 1954 report was far from conclusive – the dingoes may just have moved elsewhere. And it concluded: “clearly aerial baiting was not effective”.

But there was an important caveat:

It is important to emphasise that, though this aerial baiting campaign was a failure, such a conclusion does not necessarily apply to any other campaign.

On the strength of that, aerial baiting programs continued.

Not much has changed

Despite millions of baits applied annually to the environment since the 1940s, Australia’s biodiversity has plummeted.

What’s more, developments in the technology haven’t come far. Raw meat baits eventually replaced dry baits in some areas. Strychnine was superseded by 1080, a less harmful poison to non-target native species, and less persistent in the environment.

Trials in the 1980s brought the bait-to-kill rate down to 750 to 1 (baits per dingo carcass recovered). This was considered a cost-effective and successful outcome.

Soon after, aerial baiting found a new market, becoming the frontline defence against Australia’s plummeting biodiversity from invasive predators.

Baits are not benign to marsupials

In 2008, the Australian Pesticides and Veterinary Medicines Authority imposed a limit of ten baits per kilometre to reduce risk to non-target species.

Pest control agencies need four times that amount of poison to achieve a successful kill rate. Yet planes have been dispensing baits at this lower and ineffective rate since 2008.

Why? It seems a balance between wildlife safety and effective canine or predator eradication isn’t possible with this technology.




Read more:
Dingoes found in New South Wales, but we’re killing them as ‘wild dogs’


In fact, it has been impossible to accurately trace the fate of baits thrown from aeroplanes into remote terrain. Even ground baiting trials have proved difficult to monitor. A 2018 trial found non-target species consumed more than 71% of ground-laid meat baits, including ravens, crows, goannas, monitor lizards, marsupials and ants.

Four young dingoes died during this trial, representing only a 1.25% uptake by target. Despite monitoring with cameras and sand traps, 599 baits out of 961 in the trial disappeared without a trace.

These baits are not benign. Repeat doses can kill marsupials; non-lethal doses can kill pouch young. Secondary poisoning can also be lethal. Applying this outdated technology to vulnerable bushfire regions is from a historical viewpoint, potentially hazardous.

Surely there’s another way

There are new technologies available to help protect and repair Australia’s fragile and broken ecosystems. Remote surveillance, drones, AI, heat sensing equipment, and more could locate populations and dispatch dangerous animals.




Read more:
Guardian dogs, fencing, and ‘fladry’ protect livestock from carnivores


If aerial baiting continues, aerial surveillance could at least follow the fate of the one million baits and tell us what and who is eating them – who lives and who dies in the stripped-bare landscape.

One thing is for certain: halting the program would prevent hundreds of thousands of these poisoned meat baits ending up in the stomachs of our treasured native animals.The Conversation

Justine M. Philip, Doctor of Philosophy, Ecosystem Management, Museums Victoria

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

Sure, save furry animals after the bushfires – but our river creatures are suffering too


Jamie Pittock, Australian National University

The hellish summer of bushfires in southeast Australia triggered global concern for our iconic mammals. Donations flooded in from at home and around the world to help protect furry species.

But there’s a risk the government and public responses will not see the fish for the koalas.

Of the 113 priority fauna species identified by the federal government as worst impacted by bushfires, 61 (54%) are freshwater species that live in or around our inland rivers, such as fish, frogs, turtles and the iconic platypus.

These animals and ecosystems were already struggling due to prolonged drought and mismanagement of the Murray Darling Basin. Saving koalas and other mammals is of course important, but freshwater species should also be a priority for post-fire environmental programs.

A picture of devastation

The government’s priority species list includes three turtle species, 17 frogs, 22 crayfish, 17 fish and the platypus. Rounding out the list is an alpine stonefly, although many other invertebrates are also likely to be affected (as well as other species that depend on moist, streamside forest habitats).

Excluding tropical savannah, the recent bushfires burnt more than 7.7 million hectares in Victoria, South Australia, New South Wales, Queensland and Western Australia. Rainforests and riparian (riverside) forests were extensively damaged along the Australian east coast and alps. These are normally moist environments, which are not adapted to fire.

Plant and animal species at the edge of waterways, in peat wetlands and in riverside forests are likely to have been burnt or killed by heat, such as crustaceans , lizards, and corroboree and mountain frogs in the alps and east coast rainforests.




Read more:
Fire almost wiped out rare species in the Australian Alps. Feral horses are finishing the job


Burnt riverside forests no longer shade the water, making water temperatures hotter and leading to increased evaporation that may stress surviving wildlife. The loss of vegetation cover also leaves prey exposed to predators.

Following recent rain, water flowing into rivers has washed ash into streams. This clogs fish gills and brings nutrients that drive algal blooms. Sediment washed into waterways fills in the gaps between rocks and holes in river beds – places where many species shelter and breed. For instance, the River Murray catchment’s last population of Macquarie perch was impacted as rain washed ash and sediment into Mannus Creek in southern NSW.

Fires tend to burn forests in patches, sometimes leaving refuges for land-based animals. However fire damage to waterways flows downstream, systematically degrading the habitat of aquatic animals by leaving little clean water to hide in.

Bushfire silt clogging the usually pristine Tambo river in the Victorian high country in January.
David Crosling/AAP

Long-term damage

The devastating impact of the fires in river environments may be long-lived.

When aquatic animals species are wiped out in particular rivers, they may not be able to recolonise from surviving populations in other unconnected rivers.

Some species will invariably now be closer to extinction. For example many key peat swamp habitats of the critically endangered northern corroboree frog have been burnt in the Bogong Peaks and Brindabella mountains of NSW and the ACT.




Read more:
The sweet relief of rain after bushfires threatens disaster for our rivers


And after fires, fast-growing young eucalyptus forests transpire much more water than older burnt trees. This may reduce inflows into streams for a century.

The recent bushfires followed several years of extreme drought across much of Australia. In the Murray-Darling Basin, these challenges were compounded by poor water management that contributed to dried-up rivers and mass fish deaths.

Water-sharing rules in the basin determine how much water is allocated to agriculture and the environment. Current water-sharing plans do not explicitly include allocations to manage losses due to climate change, and as the plans will only be updated once a decade, it is questionable whether they will be adjusted to sustain flows needed to conserve threatened species.

Much corroboree frog habitat was destroyed during the fires.
Melbourne Zoo

Here’s what to do

After the fires, government officials and scientists rescued a number of “insurance” populations of threatened aquatic animals such as turtle and fish species, and took them to captive breeding facilities, such as the stocky galaxias fish in the alps. We must ensure healthy habitat is available for these animals to re-establish viable populations when released.

In the short term, we must protect surviving and regenerating habitat. Government programs are off to a good start in promising to cull feral predators such as cats and foxes, as well as grazing animals such as pigs, deer and goats. The NSW and Victorian governments must also remove feral horses in the Australian Alps that are damaging the swamp habitats and streams.

Now so many infested riverside forests are accessible, it is a key time to control weed regrowth.




Read more:
Last summer’s fish carnage sparked public outrage. Here’s what has happened since


In the medium term, we should expand programs to fence livestock out of waterways, install other watering points for these animals and revegetate stream banks.

Deep holes in rivers and streams with cool water are important refuges for aquatic animals, and ways to restore them should be investigated.

Impediments to fish migration, such as weirs, should be removed or fish “ladders” installed to aid fish movement. Aquatic species often won’t breed unless the water is the right temperature in the right season; to prevent the release of overly cold water from the bottom of dams, better water release structures should be installed.

Years of drought meant rivers and aquatic life were already vulnerable before the fires.
Dean Lewins/AAP

An opportunity for change

Successive governments have been asleep at the tiller when it comes to threatened aquatic animals. Official recovery plans for many fire-affected species have not been adequately funded or implemented.

In the Murray-Darling Basin for example, a native fish strategy was shelved in 2013 after the NSW government reportedly pulled funding.

The impending release of a new fish strategy, and other post-fire recovery actions, are an opportunity for governments to right past wrongs and ensure our precious freshwater species thrive into the future.The Conversation

Jamie Pittock, Professor, Fenner School of Environment & Society, Australian National University

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

B&Bs for birds and bees: transform your garden or balcony into a wildlife haven



Wes Mountain/The Conversation, CC BY-NC

Judith Friedlander, University of Technology Sydney

Just like humans, animals like living near coastal plains and waterways. In fact, cities such as Sydney and Melbourne are “biodiversity hotspots” – boasting fresh water, varied topographies and relatively rich soil to sustain and nourish life.

Recent research showed urban areas can support a greater range of animals and insects than some bushland and rural habitat, if we revegetate with biodiversity in mind.




Read more:
How you can help – not harm – wild animals recovering from bushfires


Urban regeneration is especially important now, amid unfathomable estimates that more than one billion animals were killed in the recent bushfires. Even before the fires, we were in the middle of a mass extinction event in Australia and around the world.

Losing animals, especially pollinators such as bees, has huge implications for biodiversity and food supplies.

My team and I are creating a B&B Highway – a series of nest boxes, artificial hollows and pollinating plants – in Sydney and coastal urban areas of New South Wales. These essentially act as “bed and breakfasts” where creatures such as birds, bees, butterflies and bats can rest and recharge. Everyday Australians can also build a B&B in their own backyards or on balconies.

City living for climate refugees

I spoke to Charles Sturt University ecologist Dr Watson about the importance of protecting animals such as pollinators during the climate crisis. He said:

The current drought has devastated inland areas – anything that can move has cleared out, with many birds and other mobile animals retreating to the wetter, more temperate forests to the south and east.

So, when considering the wider impacts of these fires […] we need to include these climate refugees in our thinking.

Native birds like the white-winged triller have been spotted in urban areas.
Shutterstock

Many woodland birds such as honeyeaters and parrots have moved in droves to cities, including Sydney, over the last few years because of droughts and climate change, attracted to the rich variety of berries, fruits and seeds.

I also spoke to BirdLife Australia’s Holly Parsons, who said last year’s Aussie Backyard Bird Count recorded other inland birds – such as the white-winged triller, the crimson chat, pied honeyeater, rainforest pigeons and doves – outside their usual range, attracted to the richer food variety in coastal cities.




Read more:
To save these threatened seahorses, we built them 5-star underwater hotels


What’s more, there have been increased sightings of powerful owls in Sydney and Melbourne, squirrel gliders in Albury, marbled geckos in Melbourne, and blue-tongue lizards in urban gardens across south-east Australia.

With so many birds and pollinators flocking to the cities, it’s important we support them with vegetated regions they can shelter in, such as through the B&B Highway we’re developing.

The B&B Highway: an urban restoration project

B&Bs on our “highway” are green sanctuaries, containing pollinating plants, water and shelters such as beehives and nesting boxes.




Read more:
Spiders are threatened by climate change – and even the biggest arachnophobes should be worried


We’re setting up B&Bs across New South Wales in schools and community centres, with plans to expand them in Melbourne, Brisbane and other major cities. In fact, by mid-2020, we’ll have 30 B&Bs located across five different Sydney municipalities, with more planned outside Sydney.

The NSW Department of Education is also developing an associated curriculum for primary and early high school students to engage them in ecosystem restoration.

One of the biodiversity havens the author developed to attract pollinators.
Author provided

If you have space in your garden, or even on a balcony, you can help too. Here’s how.

For birds

Find out what bird species live in your area and which are endangered using the Birdata directory. Then select plants native to your area – your local nursery can help you out here.

The type of plants will vary on whether your local birds feed on insects, nectar, seed, fruit or meat. Use the guide below.



Wes Mountain/The Conversation, CC BY-ND

More tips

Plant dense shrubs to allow smaller birds, such as the superb fairy-wren, to hide from predatory birds.

Order hollows and nesting boxes from La Trobe University to house birds, possums, gliders and bats.

Put out water for birds, insects and other animals. Bird baths should be elevated to enable escape from predators. Clean water stations and bowls regularly.

For native stingless bees

If you live on the eastern seaboard from Sydney northward, consider installing a native stingless beehive. They require very little maintenance, and no permits or special training.

These bees are perfect for garden pollination. Suppliers of bees and hives can be found online – sometimes you can even rescue an endangered hive.

A blue banded bee at a B&B rest stops in NSW.
Author provided

Also add bee-friendly plants – sting or no sting – to your garden, such as butterfly bush, bottlebrush, daisies, eucalyptus and angophora gum trees, grevillea, lavender, tea tree, honey myrtle and native rosemary.

For other insects

Wherever you are in Australia, you can buy or make your own insect hotel. There is no standard design, because our gardens host a wide range of native insects partial to different natural materials.

An insect hotel. Note the holes, at a variety of depths, drilled into the material.
Dietmar Rabich/Wikimedia Commons, CC BY-SA

Building your insect hotel

Use recycled materials (wooden pallets, small wooden box or frames) or natural materials (wood, bamboo, sticks, straw, stones and clay).

Fill gaps in the structure with smaller materials, such as clay and bamboo.

In the wood, drill holes ranging from three to ten millimetres wide for insects to live in. Vary hole depths for different insects – but don’t drill all the way through. They shouldn’t be deeper than 30 centimetres.

Give your hotel a roof so it stays dry, and don’t use toxic paints or varnishes.

Place your insect hotel in a sheltered spot, with the opening facing the sun in cool climates, and facing the morning sun in warmer climates.

Apartment-dwellers can place their insect hotels on a balcony near pot plants. North-facing is often best, but make sure it’s sheltered from harsh afternoon sunshine and heavy rain.The Conversation

Judith Friedlander, Post-graduate Researcher, Institute for Sustainable Futures, University of Technology Sydney

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

From crocodiles to krill, a warming world raises the ‘costs’ paid by developing embryos




Dustin Marshall, Monash University

Apart from mammals and birds, most animals develop as eggs exposed to the vagaries of the outside world. This development is energetically “costly”. Going from a tiny egg to a fully functioning organism can deplete up to 60% of the energy reserves provided by a parent.

In cold-blooded animals such as marine invertebrates (including sea stars and corals), fish and reptiles, and even insects, embryonic development is very sensitive to changes in the temperature of the environment.

Thus, in a warming world, many cold-blooded species face a new challenge: developing successfully despite rising temperatures.




Read more:
Curious Kids: why do eggs have a yolk?


For our research, published today in Nature Ecology and Evolution, we mined existing literature for data on how temperature impacts the metabolic and development rates of 71 different species, ranging from tropical crocodiles to Antarctic krill.

We found over time, species tend to fine-tune their physiology so that the temperature of the place they inhabit is the temperature needed to minimise the “costs” of their embryonic development.

Temperature increases associated with global warming could substantially impact many of these species.

The perfect weather to grow an embryo

The energy costs of embryonic development are determined by two key rates. The “metabolic” rate refers to the rate at which energy is used by the embryo, and the “development” rate determines how long it takes the embryo to fully develop, and become an independent organism.

Both of these rates are heavily impacted by environmental temperature. Any change in temperature affecting them is therefore costly to an embryo’s development.

Generally, a 10°C increase in temperature will cause an embryo’s development and metabolic rate to more than triple.

This photo shows a developing sea urchin, from egg (top left) to larva, to a metamorphosed (matured into adult form) individual.
Dustin Marshall, Author provided

These effects partially cancel each other out. Higher temperatures increase the rate at which energy is used (metabolic), but shorten the developmental time.

But do they balance out effectively?

What are the costs?

For any species, there is one temperature that achieves the perfect energetic balance between relatively rapid development and low metabolism. This optimal temperature, also called the “Goldilocks” temperature, is neither too hot, nor too cold.

When the temperature is too cold for a certain species, development takes a long time. When it’s too hot, development time decreases while the metabolic rate continues to rise. An imbalance on either side can negatively impact a natural population’s resilience and ability to replenish.

As an embryo’s developmental costs increase past the optimum, mothers must invest more resources into each offspring to offset these costs.

When offspring become more costly to make, mothers make fewer, larger offspring. These offspring start life with fewer energy reserves, reducing their chances of successfully reproducing as adults themselves.

Thus, when it comes to embryonic development, higher-than ideal temperatures pack a nasty punch for natural populations.

Since the temperature dependencies of metabolic rate and development rate are fairly similar, the slight differences between them had gone unnoticed until recently.




Read more:
Why cold-blooded animals don’t need to wrap up to keep warm


Embryos at risk

For each species in our study, we found a narrow band of temperatures that minimised developmental cost. Temperatures that were too high or too low caused massive blow-outs in the energy budget of developing embryos.

This means temperature increases associated with global warming are likely to have bigger impacts than previously predicted.

Predictions of how future temperature changes will affect organisms are often based on estimates of how temperature affects embryo survival. These measures suggest small temperature increases (1°C-2°C) do not reduce embryo survival by much.

But our study found the developmental costs are about twice as high, and we had underestimated the impacts of subtle temperature changes on embryo development.

In the warming animal kingdom, there are winners and losers

Some good news is our research suggests not all species are facing rising costs with rising temperatures, at least initially.

We’ve created a mathematical framework called the Developmental Cost Theory, which predicts some species will actually experience slightly lower developmental costs with minor increases in temperature.




Read more:
Flipping the genetic ‘switch’ that makes many animals look alike as embryos


In particular, aquatic species (fish and invertebrates) in cool temperate waters seem likely to experience lower costs in the near future. In contrast, certain tropical aquatic species (including coral reef organisms) are already experiencing temperatures that exceed their optimum. This is likely to get worse.

It’s important to note that for all species, increasing environmental temperature will eventually come with costs.

Even if a slight temperature increase reduces costs for one species, too much of an increase will still have a negative impact. This is true for all the organisms we studied.

A key question now is: how quickly can species evolve to adapt to our warming climate?The Conversation

Dustin Marshall, Professor, Marine Evolutionary Ecology, Monash University

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