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Picture of Myotis myotis in flight.
A greater mouse-eared bat (Myotis myotis) in flight. This species can imitate a hornet’s buzz to ward off predators.PHOTOGRAPH BY WILDLIFE GMBH / ALAMY STOCK PHOTO

These bats imitate hornets to avoid being eaten by owls

Mouse-eared bats make sounds like buzzing hornets, in an apparent attempt to avoid avian predation—a remarkable adaptation not previously seen in a mammal

BYSOFIA QUAGLIA

PUBLISHED MAY 9, 2022

• 7 MIN READ

Mimicry is widespread in the animal kingdom.

Some caterpillars can make themselves look like venomous snakes. The chicks of an Amazonian bird called the cinereous mourner shapeshift into poisonous larvae. Flower-loving hoverflies evolved to look just like stinging, unpalatable wasps.

These are all examples of Batesian mimicry, an evolutionary trick which leads a relatively harmless animal to copy a more dangerous species to scare off would-be predators.

But this specific type of mimicry is almost always visual in nature, so far as we know. And it’s most commonly found in insects, birds, and reptiles.

Now, for the first time, a type of acoustic mimicry has been observed in mammals. A study published May 9 in Current Biology found that a common European species, the greater mouse-eared bats, seems to imitate the buzzing sound of hornets—presumably to avoid being eaten by owls.

“We discovered that a mammal mimics the sound of an insect to scare a predatory bird,” says Danilo Russo, the lead author of the paper and an ecology professor at the Università degli Studi di Napoli Federico II, in Italy. “This is an amazing evolutionary interaction involving three species that are evolutionarily distant from one another.”

What’s the buzz?

Greater mouse-eared bats, also known as Myotis myotis, are a widespread European bat species that likes to munch on insects, especially beetles. They hang out in colonies in the woodlands and forest edges, roosting in caves underground for most of the year, or in buildings during the summer. They are often preyed upon by various birds, including barn owls (Tyto alba) and tawny owls (Strix aluco), especially when leaving or returning to their roosts.

Back in 1999, Russo was working to set up a call library for echolocation calls of European bats and collecting data about how various species communicate amongst themselves. While extracting a small mouse-eared bat from a mist-net, holding it in his hands, the creature started shivering and emitting a continuous, intense buzz, Russo says. Russo was surprised.

“My very first thought was… it sounds like hornets, or wasps!”

Initially, the researchers speculated that the buzzing was just an everyday distress call. But the sound was so obviously similar to an insect that a hypothesis originated almost immediately, Russo says, and, finally, years later, they decided to test it: Could it be that the bats were imitating hornets or bees?

Russo himself had collected pellets of barn owls in the past, at the entrance to a cave where these bats roost. “Believe it or not, the pellets contained a lot of bat skulls,” he says, so he felt it was not impossible these bats “may have, evolutionarily speaking, ‘made’ a very extreme attempt to deter [owls] to escape.”

Giving a hoot

In the current study, Russo and colleagues first compared the bat’s buzzing sounds with those of four different species of hymenopteran insects, including honeybees (Apis mellifera) and European hornets (Vespa crabro). They analyzed the sounds according to their wavelength, frequency, call duration and more, and they found that there was a large overlap in their structure.

Owls hear a wider spectrum of wavelengths than humans. So the researchers tweaked the sound parameters to fit what an owl would hear, removing the highest pitches. They realized that the bats sounded even more similar to buzzing insects to owl ears than for human ones. “The similarity was especially strong when variables undetected by the owls… were taken out,” Russo says.

Then, through speakers, the researchers played back two insect buzzing sounds. One was the sound of a buzzing bat, the other was a bat’s social call to some captive and wild owls from two different species, barn owls and tawny owls.

Although hearing recorded bat sounds made the owls move closer to the source of the sound, it seemed to mostly jar the owls. They attempted to escape or distance themselves from the speaker, or at least inspect what was going on.

During the experiment, wild owls, which might remember getting stung by some flying insect, acted more scared and likely to try to escape compared to captive-raised owls. Russo and his team speculate this is because the captives never had an encounter with a stinging insect. However, so far, there is little scientific data on how often owls are stung by bees, hornets, and wasps on a regular basis, and whether they encounter them often.

“They surely know it is a dangerous encounter,” says Russo. That’s also why he argues this type of Batesian mimicry is probably a technique deployed when a bat has been captured and wants to buy itself some time to buzz off.

Future queries

As is always the case with such new findings, many questions remain.

Future work will have to replicate these findings in the wild, rather than in a lab, and with larger numbers of owls, in order to truly assert whether this is a type of Batesian mimicry, says Bruce Anderson, an entomology professor at Stellenbosch University, in South Africa, who was not involved in the study. Another question is whether the owls aren’t just scared by the volume of the bats’ buzzing, as they might by any other unexpected loud noise. “We may want to ask whether this is a case of mimicry or exploiting a sensory bias,” Anderson says.

It’s also still unclear whether, and to what degree, owls fear buzzing insects—although data seems to suggest that birds generally avoid nesting in cavities occupied by such insects. Researchers could also learn more about whether these buzzing sounds are unique to stinging insects or if other neutral insects can produce them. It would also be nice to test if owls who have been stung react with more fear than those who haven’t, according to David Pfennig, a biology professor at the University of North Carolina at Chapel Hill, who was not involved in the study.

While mimicry is common and some cases of Batesian mimicry are well-known, much about it remains mysterious and striking, says Pfennig. He says that’s why findings like this are important. “Batesian mimicry provides some of our best examples of how natural selection can produce remarkable adaptation, including between very distantly related groups of organisms,” Pfennig says. There are other examples of acoustic mimicry between different species, like how burrowing owls can make hissing sounds that resemble rattlesnakes, but a mammal copying an insect seems to be a real first.

In the future, the scientists would like to fine-tune and expand their research.

“While it is always useful to validate observations in the field, our results were crystal-clear,” Russo says. “It would be interesting to find similar strategies in other species.” With over 1,400 bat species, as well as a handful of non-bat vertebrate species that buzz when disturbed, Russo guesses other species besides the one they studied may use the same trick.

The strategy of animals in cavities mimicking scary sounds to avoid predators could be, in fact, widespread, says Anastasia Helen Dalziell, an ornithology researcher at University of Wollongong, in Australia, who was not involved in the study.

“Most of what we know about mimicry has been gained from studies of visual mimicry, but in principle, mimetic signals could operate in any sensory [type],” says Dalziell. “It’s really great to have another example of acoustic mimicry… to help encourage a broader investigation of mimicry.”

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New Sorghum Variety Will Help Farmers Increase Sorghum Yields

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Benjamin Kohl, Ph.D.

Feb 02, 2022

Purdue University professor, Dr. Tesfaye Mengiste, looks at sorghum infected with anthracnose. Mengiste led a team of researchers who identified a single gene that confers broad resistance to the fungal disease.
Purdue University professor, Dr. Tesfaye Mengiste, looks at sorghum infected with anthracnose. Mengiste led a team of researchers who identified a single gene that confers broad resistance to the fungal disease. Photo Credit: Purdue University

Feed the Future Innovation Lab for Collaborative Research on Sorghum and Millet (SMIL) supports research that provides natural resistance to pathogens and pests in Ethiopian farm fields

Scientists with SMIL have developed a sorghum variety that provides natural resistance to pathogens and pests that have crippled the crop in humid, lowland areas of western Ethiopia.

Their research is reported in the January 9 issue of The Plant Cell, a journal of the American Society of Plant Biologists.

Dr. Timothy Dalton, director of SMIL — based at Kansas State University — said the researchers’ work will “serve the broader sorghum development community and is a flagship global good, public characteristic of the U.S. land grant mission.”

The SMIL, led by Dalton, funded work in Ethiopia and West Africa to map genes and explore more than 2,000 pieces of germplasm in numerous field trials spanning several years.

“The new sorghum variety, called Merera, has multiple benefits, including resistance to pathogens and birds, and it yields better than current varieties that Ethiopian farmers have,” said Dr. Tesfaye Mengiste, a professor of botany and plant pathology at Purdue University, and the principal investigator for the research.

Mengiste said Merera has shown resistance to Anthracnose, a devastating fungal disease that attacks all parts of the plant — leaves, stalk and head — leaving almost nothing to be used for food (sorghum’s primary use in Africa), biofuels or animal feed (the primary use of sorghum in the United States).

“With these improved traits and yield potential, it can mean a better livelihood for (farmers),” Mengiste said.

A newly discovered gene, named Anthracnose Resistance Gene1, or ARG1, is unique, according to Mengiste.

“Although some natural resistance to fungal disease was known in sorghum, genes that confer widespread resistance have not been identified,” he said. “It is remarkable that a single gene leads to resistance across a broad spectrum of fungi and multiple strains of the Anthracnose fungus.”

Mengiste cited recent results with Merera that indicate up to a 43% increase in sorghum yields, which has led to increased income for smallholder farmers.

In 2013, USAID invested $13.7 million to establish the SMIL at Kansas State University. The lab’s primary focus is to improve the productivity, disease resistance, agronomy and economics of sorghum and millet in six partner countries.

In 2018, USAID renewed its commitment to SMIL, awarding $14 million over five years to continue the project’s work.

USAID funds several Feed the Future Innovation Labs across the country to harness the capacity of U.S. land grant institutions, other universities and the private sector to improve food security globally.

The sorghum variety recently developed for Ethiopia — while directly benefitting farmers in that country — is much like many other Feed the Future projects that aim to build knowledge to help farmers throughout the world, including the United States.

“Through this collaborative research supported by SMIL and the funding through USAID, we will continue to explore the rich Ethiopian germplasm to come up with the next resilient and high-yielding varieties,” Mengiste said. “With better leveraging of recent genetic technologies, we will expedite the development of the new generation of varieties or those in the pipeline.”

More information about SMIL, please visit https://smil.k-state.edu.

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New Sorghum Variety Will Help Farmers Increase Sorghum Yields and has Resistance to Pathogens and Birds

AGRILINKS

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Benjamin Kohl, Ph.D.

Feb 02, 2022

Purdue University professor, Dr. Tesfaye Mengiste, looks at sorghum infected with anthracnose. Mengiste led a team of researchers who identified a single gene that confers broad resistance to the fungal disease.
Purdue University professor, Dr. Tesfaye Mengiste, looks at sorghum infected with anthracnose. Mengiste led a team of researchers who identified a single gene that confers broad resistance to the fungal disease. Photo Credit: Purdue University

Feed the Future Innovation Lab for Collaborative Research on Sorghum and Millet (SMIL) supports research that provides natural resistance to pathogens and pests in Ethiopian farm fields

Scientists with SMIL have developed a sorghum variety that provides natural resistance to pathogens and pests that have crippled the crop in humid, lowland areas of western Ethiopia.

Their research is reported in the January 9 issue of The Plant Cell, a journal of the American Society of Plant Biologists.

Dr. Timothy Dalton, director of SMIL — based at Kansas State University — said the researchers’ work will “serve the broader sorghum development community and is a flagship global good, public characteristic of the U.S. land grant mission.”

The SMIL, led by Dalton, funded work in Ethiopia and West Africa to map genes and explore more than 2,000 pieces of germplasm in numerous field trials spanning several years.

“The new sorghum variety, called Merera, has multiple benefits, including resistance to pathogens and birds, and it yields better than current varieties that Ethiopian farmers have,” said Dr. Tesfaye Mengiste, a professor of botany and plant pathology at Purdue University, and the principal investigator for the research.

Mengiste said Merera has shown resistance to Anthracnose, a devastating fungal disease that attacks all parts of the plant — leaves, stalk and head — leaving almost nothing to be used for food (sorghum’s primary use in Africa), biofuels or animal feed (the primary use of sorghum in the United States).

“With these improved traits and yield potential, it can mean a better livelihood for (farmers),” Mengiste said.

A newly discovered gene, named Anthracnose Resistance Gene1, or ARG1, is unique, according to Mengiste.

“Although some natural resistance to fungal disease was known in sorghum, genes that confer widespread resistance have not been identified,” he said. “It is remarkable that a single gene leads to resistance across a broad spectrum of fungi and multiple strains of the Anthracnose fungus.”

Mengiste cited recent results with Merera that indicate up to a 43% increase in sorghum yields, which has led to increased income for smallholder farmers.

In 2013, USAID invested $13.7 million to establish the SMIL at Kansas State University. The lab’s primary focus is to improve the productivity, disease resistance, agronomy and economics of sorghum and millet in six partner countries.

In 2018, USAID renewed its commitment to SMIL, awarding $14 million over five years to continue the project’s work.

USAID funds several Feed the Future Innovation Labs across the country to harness the capacity of U.S. land grant institutions, other universities and the private sector to improve food security globally.

The sorghum variety recently developed for Ethiopia — while directly benefitting farmers in that country — is much like many other Feed the Future projects that aim to build knowledge to help farmers throughout the world, including the United States.

“Through this collaborative research supported by SMIL and the funding through USAID, we will continue to explore the rich Ethiopian germplasm to come up with the next resilient and high-yielding varieties,” Mengiste said. “With better leveraging of recent genetic technologies, we will expedite the development of the new generation of varieties or those in the pipeline.”

More information about SMIL, please visit https://smil.k-state.edu.

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To find out how insects are doing, scientists are going to the birds.

The EntoGEM project is finding overlooked data on insect populations in avian studies

A red-backed shrike male with grasshopper prey
Studies of birds such as this red-backed shrike (Lanius collurio) could hold valuable data on the insects they eat.HENNY BRANDSMA/MINDEN PICTURES

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For years, entomologists have worried about what appears to be a global decline in insect populations. But data on insect trends can be hard to come by. Scientists have studied relatively few of the some 900,000 living insect species they have named so far, and have yet to name millions more.

Now, researchers say one of the bug world’s deadliest enemies—birds—could offer much-needed help in tracking insect numbers. That’s because studies of birds often contain substantial information about the insects they eat.

Those bird-related data are pretty much missing from current studies of insect declines, says Chris Elphick, a conservation biologist at the University of Connecticut (UConn), Storrs, and a co-organizer of EntoGEM, a research effort launched in 2019 that is combing the scientific literature for insect data. The project’s initial review of bird studies, for example, has unearthed some three dozen that tracked insect populations for 10 years or longer. (The researchers presented those findings at a recent Entomological Society of America meeting and are now preparing to submit a paper to a journal.)

Elphick and Danielle Schwartz, a conservation biologist at UConn who is also involved in EntoGEM, recently spoke to Science about the search for more insect information. The interview was edited for clarity and brevity.

Q: Why should we be looking for more data on insect populations?

Chris Elphick: People talk about global insect decline, but we don’t really know what’s going on globally, because we don’t have data sets from most parts of the world. We have good evidence that insects are declining in lots of places. But it’s also clear that insects are not declining everywhere and that not all insects are declining. The data we have are patchy and biased toward Western Europe and parts of North America. Our hope is that even if [new information] doesn’t change the story, it will give us more confidence in the current story because it will be more comprehensive. We’re losing biodiversity at such a rate that we really need to find ways to use the information that we have already and get it all in one place so that we can use it more effectively.

Q: What made you think to look for insect data in bird studies?

C.E.: It kind of started because we’re not actually entomologists! I’ve studied birds my entire career. Eliza [Grames, an ecologist at the University of Nevada, Reno, who was then a Ph.D. student studying birds], and another graduate student—entomologist Graham Montgomery, now at the University of California, Los Angeles—got thinking about how we do a better job of finding and using data we’ve already collected. Eliza initiated EntoGEM and started developing [software] tools for trying to search the literature more effectively. We started finding papers with data sets that were not mentioned in any of the analyses looking at insect declines. A lot of those papers were on birds because ornithologists were interested in what the birds were eating.

Q: Why were those data overlooked?

Danielle Schwartz: The first thing is the terminology. There’s a lot of different terminology that we’ve seen that wouldn’t necessarily imply insects right off the bat—[such as references to] “protein food.”

C.E.: It may often just be as simple as not putting the right keywords into the front end of the paper, so the search engines just don’t find it. As an ornithologist you might not use the word “caterpillar” in the title, abstract, or the keywords—and that’s the information that people search. [In addition,] if you’re collecting caterpillars because you want to know how much food there is for forest songbirds, you might mention caterpillars but you’re not going to list all of the species. Those data sets don’t have the level of detail that an entomologist might be interested in. But if you’re just trying to get a gross sense of whether forest caterpillars are declining, that might still be a useful data set.

Q: What has EntoGEM done so far with ornithology papers?

D.S.: We did an initial search and came up with 35,018 papers. Before reading through the abstracts, we use another program that Eliza wrote to [filter out those] that wouldn’t be relevant. And then once we start seeing a trend—for example, when I started seeing a lot of papers about snails—I can search by keyword and filter those out.

C.E.: We’re always trying to find ways to streamline [the process]. You can use [initial reviews] to build a statistical model to predict which of the remaining papers are going to be relevant. For every paper, we have a prediction of how likely it is to be relevant.

Q: How many papers have you identified data in so far?

D.S.: Somewhere around 150. … We’ve found something like 40 that have data that span at least a 10-year period. The studies are mostly clustered in Western Europe and North America. But we are starting to find a few examples from parts of the world [with] less information.

Q: What’s an example of useful data you’ve found?

C.E.: One of the first ones that [Grimes] found is this study of Harlequin ducks in Iceland. Harlequin ducks are these pretty fancy-looking ducks that nest on mountain streams. There’s this group [of researchers] in Iceland that has been studying them since the 1970s. They measured the number of chironomids—little midges—every year, because these ducks eat chironomids. They have almost a 30-year data set.

What I like about this duck example is that people don’t generally think about ducks eating insects. And it’s not the kind of place where you would think to go looking for a longtime series on insect populations. It’s an example of the kind of information that’s out there if you just go looking for it.

Q: Besides ornithology, are there other fields that might have overlooked insect data?

C.E.: Absolutely. There’s probably an endless number of places to look. Herpetologists, mammalogists … I’m sure there are botanists who collect a lot of data on insects because insects eat plants all the time. People who do forensics work collect data on insects. Whether they do it in a way that could contribute to understanding population change, I don’t know.


doi: 10.1126/science.ada0301

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The world’s largest organism is slowly being eaten by deer

November 23, 2021 9.37am EST Updated November 24, 2021 6.47pm EST

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  1. Richard Elton WaltonPostdoctoral Research Associate in Biology, Newcastle University

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Richard Elton Walton is affiliated with Friends of Pando as a volunteer.

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In the Wasatch Mountains of the western US on the slopes above a spring-fed lake, there dwells a single giant organism that provides an entire ecosystem on which plants and animals have relied for thousands of years. Found in my home state of Utah, “Pando” is a 106-acre stand of quaking aspen clones.

Although it looks like a woodland of individual trees with striking white bark and small leaves that flutter in the slightest breeze, Pando (Latin for “I spread”) is actually 47,000 genetically identical stems that arise from an interconnected root network. This single genetic individual weighs around 6,000 tonnes. By mass, it is the largest single organism on Earth.

Aspen trees do tend to form clonal stands elsewhere, but what makes Pando interesting is its enormous size. Most clonal aspen stands in North America are much smaller, with those in western US averaging just 3 acres.

View across a valley with trees highlighted in green
Aerial outline of Pando, with Fish Lake in the foreground. Lance Oditt / Friends of Pando, Author provided

Pando has been around for thousands of years, potentially up to 14,000 years, despite most stems only living for about 130 years. Its longevity and remoteness mean a whole ecosystem of 68 plant species and many animals have evolved and been supported under its shade. This entire ecosystem relies on the aspen remaining healthy and upright. But, although Pando is protected by the US National Forest Service and is not in danger of being cut down, it is in danger of disappearing due to several other factors.

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Deer are eating the youngest ‘trees’

Overgrazing by deer and elk is one of the biggest worries. Wolves and cougars once kept their numbers in check, but herds are now much larger because of the loss of these predators. Deer and elk also tend to congregate in Pando as the protection the woodland receives means they are not in danger of being hunted there.

Three deer in an aspen forest
Well-disguised deer eating Pando shoots. Lance Oditt / Friends of Pando, Author provided

As older trees die or fall down, light reaches the woodland floor which stimulates new clonal stems to start growing, but when these animals eat the tops off newly forming stems, they die. This means in large portions of Pando there is little new growth. The exception is one area that was fenced off a few decades ago to remove dying trees. This fenced-off area has excluded elk and deer and has seen successful regeneration of new clonal stems, with dense growth referred to as the “bamboo garden”.

Diseases and climate change

Older stems in Pando are also being affected by at least three diseases: sooty bark canker, leaf spot and conk fungal disease. While plant diseases have developed and thrived in aspen stands for millennia, it is unknown what the long-term effect on the ecosystem may be, given that there is a lack of new growth and an ever-growing list of other pressures on the clonal giant.

The fastest-growing threat is that of climate change. Pando arose after the last ice age had passed and has dealt with a largely stable climate ever since. To be sure, it inhabits an alpine region surrounded by desert, meaning it is no stranger to warm temperatures or drought. But climate change threatens the size and lifespan of the tree, as well as the whole ecosystem it hosts.

Although no scientific studies have focused specifically on Pando, aspen stands have been struggling with climate change-related pressures, such as reduced water supply and warmer weather earlier in the year, making it harder for trees to form new leaves, which have led to declines in coverage. With more competition for ever-dwindling water resources (the nearby Fish Lake is just out of reach of the tree’s root system), temperatures expected to continue soaring to record highs in summer, and the threat of more intense wildfires, Pando will certainly struggle to adjust to these fast-changing conditions while maintaining its size.

The next 14,000 years

Yet Pando is resilient and has already survived rapid environmental changes, especially when European settlers began inhabiting the area in the 19th century or after the rise of 20th-century recreational activities. It has dealt with disease, wildfire, and grazing before and remains the world’s largest scientifically documented organism.

Trees at sunset
Pando has survived disease, hunting and colonisation. Lance Oditt / Friends of Pando, Author provided

Despite every cause for concern, there is hope as scientists are helping us unlock the secrets to Pando’s resilience, while conservation groups and the US forest service are working to protect this tree and its associated ecosystem. And a new group called the Friends of Pando aims to make the tree accessible to virtually everyone through 360 video recordings.

Last summer, when I was visiting my family in Utah, I took the chance to visit Pando. I spent two amazing days walking under towering mature stems swaying and “quaking” in the gentle breeze, between the thick new growth in the “bamboo garden”, and even into charming meadows that puncture portions of the otherwise-enclosed centre. I marvelled at the wildflowers and other plants thriving under the dappled shade canopy, and I was able to take delight in spotting pollinating insects, birds, fox, beaver and deer, all using some part of the ecosystem created by Pando.

It’s these moments that remind us that we have plants, animals and ecosystems worth protecting. In Pando, we get the rare chance to protect all three.


This article was updated on November 24 to correct a typo: Pando is estimated to weigh 6 million kilograms not 6 million tonnes. It now reads “6,000 tonnes”.

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OCTOBER 21, 2021

Don’t underestimate rabbits: These powerful pests threaten more native wildlife than cats or foxes

by Pat Taggart, Brian Cooke, The Conversation

Don't underestimate rabbits: these powerful pests threaten more native wildlife than cats or foxes
Rabbits eventually built up a tolerance to biocontrols. Credit: Shutterstock

In inland Australia, rabbits have taken a severe toll on native wildlife since they were introduced in 1859. They may be small, but today rabbits are a key threat to 322 species of Australia’s at-risk plants and animals—more than twice the number of species threatened by cats or foxes.https://e8facf95f2a45a2fd1e278c392de6377.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html

For example, research shows even just one rabbit in two hectares of land can solely destroy every regenerating sheoak seedling. Rabbits are also responsible for the historic declines of the iconic southern hairy-nosed wombat and red kangaroo.

Our latest research looked at the conservation benefits following the introduction of three separate biocontrols used to manage rabbits in Australia over the 20th Century—all three were stunningly successful and resulted in enormous benefits to conservation.

But today, rabbits are commonly ignored or underestimated, and aren’t given appropriate attention in conservation compared to introduced predators like cats and foxes. This needs to change.

Why rabbits are such a serious problem

Simply put, rabbits are a major problem for Australian ecosystems because they destroy huge numbers of critical regenerating seedlings over more than half the continent.

Rabbits can prevent the long-term regeneration of trees and shrubs by continually eating young seedlings. This keeps ecosystems from ever reaching their natural, pre-rabbit forms. This has immense flow-on effects for the availability of food for plant-eating animals, for insect abundance, shelter and predation.

In some ecosystems, rabbits have prevented the regeneration of plant communities for 130 years, resulting in shrub populations of only old, scattered individuals. These prolonged impacts may undermine the long-term success of conservation programs to reintroduce mammals to the wild.https://googleads.g.doubleclick.net/pagead/ads?client=ca-pub-0536483524803400&output=html&h=280&slotname=5350699939&adk=2071891895&adf=780081655&pi=t.ma~as.5350699939&w=540&fwrn=4&fwrnh=100&lmt=1634968622&rafmt=1&psa=1&format=540×280&url=https%3A%2F%2Fphys.org%2Fnews%2F2021-10-dont-underestimate-rabbits-powerful-pests.html&flash=0&fwr=0&rpe=1&resp_fmts=3&wgl=1&uach=WyJXaW5kb3dzIiwiMTAuMC4wIiwieDg2IiwiIiwiOTUuMC4xMDIwLjMwIixbXSxudWxsLG51bGwsIjY0Il0.&dt=1634968622468&bpp=9&bdt=270&idt=150&shv=r20211020&mjsv=m202110200101&ptt=9&saldr=aa&abxe=1&cookie=ID%3D895ac2cb13223d7c-224f137c58cb0056%3AT%3D1628474727%3AS%3DALNI_Mbcifc_L6AwwVQop1sOsaLGpFy88g&correlator=1365095016994&frm=20&pv=2&ga_vid=575682118.1628474640&ga_sid=1634968623&ga_hid=210059594&ga_fc=1&u_tz=-300&u_his=1&u_h=864&u_w=1536&u_ah=824&u_aw=1536&u_cd=24&adx=326&ady=2217&biw=1381&bih=685&scr_x=0&scr_y=0&eid=31063260%2C31062524&oid=2&pvsid=2957186773193720&pem=278&wsm=1&ref=http%3A%2F%2Fwww.bcpc.org%2F&eae=0&fc=896&brdim=0%2C0%2C0%2C0%2C1536%2C0%2C1536%2C824%2C1396%2C685&vis=1&rsz=%7C%7CpeEbr%7C&abl=CS&pfx=0&fu=128&bc=31&ifi=1&uci=a!1&btvi=1&fsb=1&xpc=0yB8cvZkXQ&p=https%3A//phys.org&dtd=168

Things are particularly dire in arid Australia where, in drought years, rabbits can eat a high proportion of the vegetation that grows, leaving little food for native animals. Arid vegetation is slow growing and doesn’t regenerate often as rainfall is infrequent. This means rabbits can have a severe toll on wildlife by swiftly eating young trees and shrubs soon after they emerge from the ground.

Rabbits eat a high proportion of regenerating vegetation even when their population is at nearly undetectable levels. For example, it took the complete eradication of rabbits from the semi-arid TGB Osborn reserve in South Australia, before most tree and shrub species could regenerate.

Rabbits also spread weeds, cause soil erosion and reduce the ability of soil to absorb moisture and support vegetation growth.

If you control prey, you control predators

When restoring ecosystems, particularly in arid Australia, it’s common for land managers to heavily focus on managing predators such as cats and foxes, while ignoring rabbits. While predator management is important, neglecting rabbit control may mean Australia’s unique fauna is still destined to decline.

Cats and foxes eat a lot of rabbits in arid Australia and can limit their populations when rabbit numbers are low. A common argument against rabbit control is that cats and foxes will turn to eating native species in the absence of rabbits. But this argument is unfounded.

Cats and foxes may turn from rabbits to native species in the immediate short-term. But, research has also shown fewer rabbits ultimately lead to declines in cat and fox numbers, as the cats and foxes are starved of their major food source.

Regrowth could be seen from space

An effective way to deal with rabbits is to release biocontrol agents—natural enemies of rabbits, such as viruses or parasites. Our research reviewed the effects of rolling out three different biocontrols last century:

  • myxomatosis (an infectious rabbit disease), released in 1950
  • European rabbit fleas (as a vector of myxomatosis), released in 1968
  • rabbit haemorrhagic disease, released in 1995.

Each lead to unprecedented reductions in the number of rabbits across Australia.

Despite the minor interest in conservation at the time, the spread of myxomatosis led to widespread regeneration in sheoaks for over five years, before rabbit numbers built back up. Red kangaroo populations increased so much that landholders were suddenly “involved in a shooting war with hordes of kangaroos invading their properties“, according to a newspaper report at the time.

Following the introduction of the European rabbit flea, native grasses became prolific along the Mount Lofty Ranges, South Australia. Similarly, southern hairy-nosed wombats and swamp wallabies expanded their ranges.

By the time rabbit haemorrhagic disease was introduced in 1995, interest in conservation and the environment had grown and conservation benefits were better recorded.

Native vegetation regenerated over enormous spans of land, including native pine, needle bush, umbrella wattle, witchetty bush and twin-leaved emu bush. This regeneration was so significant across large parts of the Simpson and Strzelecki Deserts, it could be seen from space.

Red kangaroos became two to three times more abundant, and multiple species of desert rodent and a small marsupial carnivore (dusky hopping mouse, spinifex hopping mouse, plains rat, crest-tailed mulgara) all expanded their ranges.

But each time, after 10 to 20 years, the biocontrols stop working so well, as rabbits eventually built up a tolerance to the diseases.

So what should we do today?

Today, there are an estimated 150–200 million rabbits in Australia, we need to be on the front foot to manage this crisis. This means researchers should continually develop new biocontrols—which are clearly astonishingly successful.

But this isn’t the only solution. The use of biocontrols must be integrated with conventional rabbit management techniques, including destroying warrens (burrow networks) and harbors (above-ground rabbit shelters), baiting, fumigation, shooting or trapping.

Land managers have a major part to play in restoring Australia’s arid ecosystems, too. Land managers are required by law to control invasive pests such as rabbits, and this must occur humanely using approved and recognized methods.

They, and researchers, must take rabbit management seriously and give it equal, if not more, attention than feral cats and foxes. It all starts with a greater awareness of the problem, so we stop underestimating these small, but powerful, pests.


Explore furtherA numbers game—killing rabbits to conserve native mammals


Provided by The Conversation

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

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Benefits to Using Barn Owls for Rodent Control

Barn owls are big, beautiful biocontrol.By Stacie Clary -October 7, 20210485

Like any biocontrol option, barn owls won’t drive pest populations to zero and may need to be augmented with rodenticides occasionally (all photos courtesy Ryan Bourbour.)

Barn owls are rodent-killing machines,” said Sara Kross, a lecturer at Columbia University, “They are natural predators of gophers and voles, which can be really horrible pests for agriculture.”

For farmers, ranchers and/or land managers facing serious rodent problems, encouraging native barn owls to nest on their land can provide effective, ongoing biocontrol. The Western Sustainable Agriculture Research and Education (SARE) program has funded multiple research projects, such as one by Kross, looking at how to incorporate barn owls into a broader integrated pest management system. From this research, the program has developed a four-page “How To Guide” with tips for welcoming in barn owls to provide rodent control.

The Research

Barn owls are effective biocontrol against rodents, but like any biocontrol option, they won’t drive pest populations to zero and may need to be augmented with rodenticides occasionally.

Kross’ study looked at the frequency and level owls on farms are being exposed to rodenticides through analysis of their pellets, droppings and blood. The team looked for the effects of that rodenticide exposure on the owls.

One farm where the team has been conducting its research is Matchbook Wine Company’s vineyards in the Dunnigan Hills north of Sacramento.

“My family’s been growing wine grapes here since the 1970s, and controlling rodents is a big part of our integrated pest management program,” said Matchbook’s Greg Giguiere.

“We have 40 owl boxes on the farm. The rodent control is what we’re after, and it’s part of having an integrated system of biodiversity and biological controls to complement the chemical options we have for controlling these types of things.”

Another aspect of the project is tracking where the owls hunt. For that, adults were fitted with little GPS backpacks that recorded their movements for up to two weeks at a time before the backpacks were transferred to a different bird to record more data.

“Barn owls are an excellent study species because they come back to sleep in these boxes during the day, so we can safely recapture them,” says Ryan Bourbour, a Ph.D. student at UC Davis who is tracking the owls.

The study data is helping growers place barn owl boxes in the locations that will do them the most good and place rodenticide bait stations in the periods and places that cause the owls the least harm.

And that is very attractive to Giguiere.

“A big part of farming is being connected to the land,” he said. “So, a lot of what we do goes to that. I’ve been very interested in reducing chemical inputs into our system and moving away from a monoculture and having more biodiversity. So, it’s a very exciting program and we’re definitely on board and moving forward, and want to do even more habitats for hawks and other predators.”

Providing barn owls with artificial nest boxes on your farm and ranch helps them because natural nest sites are often a limiting factor for barn owl populations.

Are Barn Owls Right for Your Operation?

Barn owls can help keep rodent populations under control and deter rodent damage to fields, irrigation lines and equipment. As night-hunters, they’re effective at controlling mice, gophers and voles. Their boxes can also serve as hunting platforms for day-hunters like hawks, kestrels and eagles, which can help control and deter ground squirrel populations. In addition, there’s often great satisfaction knowing you’re hosting and helping these gorgeous natural predators.

If you have a serious rodent problem in your fields, barn owls can help. Providing barn owls with artificial nest boxes on your farm and ranch helps them because natural nest sites are often a limiting factor for barn owl populations.

During the mating and nesting season, barn owls are looking for a safe place to raise their young and a lot of rodents to feed them. If you already have the rodents, you just need to add owl boxes to house the barn owls.

For even better rodent control, also install raptor perches when you install barn owl boxes. Mount a wooden cross brace to a 10- to 15-foot-high pole. Hawks and kestrels will use them while hunting during the day, and barn owls use them at night.

Developed from this research, Western SARE’s free How-To Guide (western.sare.org/resources/welcome-in-barn-owls-to-provide-rodent-control/) takes you through decision-making, provides tips on how to provide nest boxes and describes how to site and maintain the boxes as well as how to determine if they are working.
Western SARE has developed multiple research-based How-To Guides for farmers and ranchers that can be downloaded for free at western.sare.org/learning-and-resources/how-to-quick-guides/.

For farmers, ranchers and/or land managers facing serious rodent problems, encouraging native barn owls to nest on their land can provide effective, ongoing biocontrol.

Read Full Post »

Benefits to Using Barn Owls for Rodent Control

Barn owls are big, beautiful biocontrol.By Stacie Clary -October 7, 20210338

Like any biocontrol option, barn owls won’t drive pest populations to zero and may need to be augmented with rodenticides occasionally (all photos courtesy Ryan Bourbour.)

Barn owls are rodent-killing machines,” said Sara Kross, a lecturer at Columbia University, “They are natural predators of gophers and voles, which can be really horrible pests for agriculture.”

For farmers, ranchers and/or land managers facing serious rodent problems, encouraging native barn owls to nest on their land can provide effective, ongoing biocontrol. The Western Sustainable Agriculture Research and Education (SARE) program has funded multiple research projects, such as one by Kross, looking at how to incorporate barn owls into a broader integrated pest management system. From this research, the program has developed a four-page “How To Guide” with tips for welcoming in barn owls to provide rodent control.

The Research

Barn owls are effective biocontrol against rodents, but like any biocontrol option, they won’t drive pest populations to zero and may need to be augmented with rodenticides occasionally.

Kross’ study looked at the frequency and level owls on farms are being exposed to rodenticides through analysis of their pellets, droppings and blood. The team looked for the effects of that rodenticide exposure on the owls.

One farm where the team has been conducting its research is Matchbook Wine Company’s vineyards in the Dunnigan Hills north of Sacramento.

“My family’s been growing wine grapes here since the 1970s, and controlling rodents is a big part of our integrated pest management program,” said Matchbook’s Greg Giguiere.

“We have 40 owl boxes on the farm. The rodent control is what we’re after, and it’s part of having an integrated system of biodiversity and biological controls to complement the chemical options we have for controlling these types of things.”

Another aspect of the project is tracking where the owls hunt. For that, adults were fitted with little GPS backpacks that recorded their movements for up to two weeks at a time before the backpacks were transferred to a different bird to record more data.

“Barn owls are an excellent study species because they come back to sleep in these boxes during the day, so we can safely recapture them,” says Ryan Bourbour, a Ph.D. student at UC Davis who is tracking the owls.

The study data is helping growers place barn owl boxes in the locations that will do them the most good and place rodenticide bait stations in the periods and places that cause the owls the least harm.

And that is very attractive to Giguiere.

“A big part of farming is being connected to the land,” he said. “So, a lot of what we do goes to that. I’ve been very interested in reducing chemical inputs into our system and moving away from a monoculture and having more biodiversity. So, it’s a very exciting program and we’re definitely on board and moving forward, and want to do even more habitats for hawks and other predators.”

Providing barn owls with artificial nest boxes on your farm and ranch helps them because natural nest sites are often a limiting factor for barn owl populations.

Are Barn Owls Right for Your Operation?

Barn owls can help keep rodent populations under control and deter rodent damage to fields, irrigation lines and equipment. As night-hunters, they’re effective at controlling mice, gophers and voles. Their boxes can also serve as hunting platforms for day-hunters like hawks, kestrels and eagles, which can help control and deter ground squirrel populations. In addition, there’s often great satisfaction knowing you’re hosting and helping these gorgeous natural predators.

If you have a serious rodent problem in your fields, barn owls can help. Providing barn owls with artificial nest boxes on your farm and ranch helps them because natural nest sites are often a limiting factor for barn owl populations.

During the mating and nesting season, barn owls are looking for a safe place to raise their young and a lot of rodents to feed them. If you already have the rodents, you just need to add owl boxes to house the barn owls.

For even better rodent control, also install raptor perches when you install barn owl boxes. Mount a wooden cross brace to a 10- to 15-foot-high pole. Hawks and kestrels will use them while hunting during the day, and barn owls use them at night.

Developed from this research, Western SARE’s free How-To Guide (western.sare.org/resources/welcome-in-barn-owls-to-provide-rodent-control/) takes you through decision-making, provides tips on how to provide nest boxes and describes how to site and maintain the boxes as well as how to determine if they are working.
Western SARE has developed multiple research-based How-To Guides for farmers and ranchers that can be downloaded for free at western.sare.org/learning-and-resources/how-to-quick-guides/.

For farmers, ranchers and/or land managers facing serious rodent problems, encouraging native barn owls to nest on their land can provide effective, ongoing biocontrol.

Read Full Post »

Laikipia village where farmers sleep in farms to deter jumbos

By CLEMENT MASOMBO | March 26th 2021 at 00:00:00 GMT +0300

Joyce Mukami from Nginyii village in Laikipia East is lucky that elephants did not destroy her crop of tomatoes. [Kibata Kihu, Standard]

The nightly routine of residents of Nginyii village in Umande ward, Laikipia County, has been upended by the invasion of elephants that descend from the nearby Lolldaiga Hills in search of food.

Locals have to brave the cold as they stand guard over their crops of tomatoes, carrots, French beans and other horticultural produce that prove irresistible to the jumbos, which destroy all fences or hedges erected to stop them from eating to their fill.

Rose Wairimu, 75, knows only too well the health issues she’s exposing herself to in the biting cold, but guarding the farms is a communal activity in which everyone is expected to pull their weight.

“They should just come and take away their animals. Since January, these jumbos only failed to invade our farms for one week. That’s the only time we enjoyed our sleep,” Wairimu said.

Despite the night vigils, Wairimu is counting heavy losses after the elephants invaded her tomato farm and laid waste to her crop. Her neighbour, Alex Ngare, did not fare any better after his crop of French beans was destroyed.

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hindu business

TN’s hill banana plantations wilt under elephant, viral attacks

A bunch of Hill banana grown in Dindigul, Tamil Nadu

Animal menace, inadequate insurance cover have resulted in shrinking acreage of the fruit

Kochi, April 20

Rampaging wild elephants coupled with Bunchy Top Banana (BTB) disease have hit Hill Banana growers in the Dindigul district of Tamil Nadu.

Found only in the Palani Hills of Dindigul, hill banana — locally called ‘Virupakshi’ — is a highly remunerative crop that can be harvested in 18-36 months .

This specific variety has a commercial importance and it caters only to Chennai market with a sales of around 50,000 fruits per day in the price range of 60-80/kg, said TVSN Veera Arasu, Secretary of the Tamil Nadu Hill Banana Growers Federation.

However, wild elephants straying into the fields in search of food and water have wrought havoc in several areas, causing financial loss to farmers.

The hill banana crop is the livelihood of farmers in 29 villages in the region.

But without any adequate insurance protection available, farmers are starved of funds to start the next crop.

“I have lost around 40 lakh in the last season due to the damage caused by wild elephants in my farm. Majority of the farmers here are scared to come back to banana cultivation,” he said.

Acreage down

Arasu, who was in Kochi recently to attend the farmers conclave organised by the Kerala Farmers Federation, told BusinessLine that the banana acreage has also come down to 3,000 acres compared to 16,000 acres five years back.

The threat of damage discourages new entrants to take up banana cultivation.

“To control the elephant menace, we have an assurance from the authorities to set up trenches and solar fencing for crop protection,” he said.

“We have successfully controlled BTB disease in the early 2000 with the help of Tamil Nadu Agriculture University. As the virus started attacking the plants again, we have approached the National Research Centre for Banana, Tiruchi, along with TNAU for remedial measures”, he said.

Highly remunerative

Among all the plantation crops, hill banana is the only crop which provides a weekly income to farmers, whereas remuneration from all other crops was on annual basis.

The Federation has been successful in obtaining GI certification for Virupakshi and Sirumalai — the two varieties of Hill Banana — a favourite fruit during the British period.

The famous Panchamritham in Palani Temple is made out of Virupakshi banana, the pulp of which is the main ingredient, he added.

 

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Daily News Blog

Predatory Birds Can Successfully Replace Pesticide Use in Agriculture

(Beyond Pesticides, March 8, 2018) Simple approaches that increase populations of vertebrate predators, like bats and falcons on farms, can reduce pesticide use, increase on-farm productivity, and conserve wildlife, according to a literature review published by researchers at Michigan State University in the journal Agriculture, Ecosystems and Environment.  The review encompasses 48 studies published over the last 150 years on the effect of human interventions to enhance natural ecosystem services. Results point not only to new methods to improve on-farm pest management, but also potential ways to engage farmers and citizen scientists in implementing these win-win strategies.

Researchers looked at a number of methods tested in the scientific literature that would increase on-farm populations of vertebrate pest predators. Broadly, discrete approaches such as installing structures like nest boxes, perches, and artificial roosts were investigated alongside more wide-ranging systems aimed at altering habitat and increasing landscape complexity. The latter includes methods such as installing field borders, increasing tree cover, reintroducing native species, and eliminating invasives.

The more discrete approaches provided a simpler, more accessible, and less expensive method of pest management when compared to approaches that require more wide-ranging landscape changes, though the benefits of those activities were not negligible. Nest boxes were found to successfully increase the abundance of predator species. Populations of western bluebirds increased by a factor of 10 when nest boxes were installed as part of a study on California vineyards, and vineyards without the nest boxes saw significantly higher pest levels when compared to those with bluebird boxes. In Europe, apple orchards that installed nest boxes for the native great tit bird saw 50% less pest damage than orchards that did not install the structures. Likewise, the installation of artificial bat roosts around Spanish rice fields led to significant declines in major moth pests over a 10 year period. When perches were installed around Australian soybean fields, raptors and other predatory birds caused a statistically significant decline in mouse populations.

The creation of field borders – strips of non-crop flowers and plants – did represent a successful method of improving populations of vertebrate pest predators. Studies reviewed found that bird abundance around these strips grew as the distance between cropland and forested areas increased, indicating potentially significant benefits of this practice for otherwise monotypic row crop farms.

In considering research on the addition of tree cover, studies have found mixed results. While some work indicates higher populations of various birds on farms of shade-grown coffee, other show species richness to be greater in sun-grown fields. That being said, studies generally indicate that increasing tree cover is likely to improve vertebrate pest control services.

Reintroducing native species can be a multifaceted, costly undertaking, and as a result of misperceptions about large carnivores, is more successful when the species is smaller, well-known, and non-threatening for people and farmers. A case study following the introduction of the New Zealand falcon into region known for its grape production found that the predators reduced fruit loss from pest bird species.

Both structural and landscape-level strategies can interact with one another. In one example, nest boxes installed to promote kestrel populations in Michigan were displaced by the widespread and invasive European starling. Although the solution to this problem is as simple as removing the nests, it indicates broader efforts may be necessary to maintain discrete approaches.

In sum, these methods provide a myriad of benefits. The economic value of vertebrate predators in reducing pests is significant. Bats alone contribute millions of dollars in pest-controlling ecosystem services – one study reviewed found that the loss of bats in Indonesian cacao fields would decrease yields by over 700 lb per hectare, a loss of $730 per year per hectare. The falcons reintroduced to New Zealand grape fields saved farmers there between $234 and $326 as a result of decreased pest bird consumption of fruit. In addition to monetary benefits, structures like nest boxes help conserve species by enhancing local populations, as occurred with the reintroduction of kestrels in Michigan.

Critically, these strategies help replace the over $15.2 billion American farmers spent purchasing pesticides in 2016. However, as researchers indicate, the true cost of pesticide use, through the poisoning of humans and animals, the displacement of pest predators, and contamination of our environment may increase that number by over $10 billion.

This review provides sound evidence in favor of farmers implementing simple, environmentally sustainable pest management methods. Researchers note the need to further investigate ways to engage farmers and citizens to participate in these activities, potentially through social networks, games such as the Ebird mobile app, and other tools. “Now that we’ve bundled these studies, we really need to set a research agenda to quantify best practices and make the results accessible to key stakeholders, such as farmers and environmentalists,” said lead author of the study Catherine Lindell, PhD to the National Science Foundation.

For more information on the benefits of not only vertebrate predators, but a wide range of wildlife species in reducing pesticide use, see Beyond Pesticides’ Wildlife Program page.

All unattributed positions and opinions in this piece are those of Beyond Pesticides.

Source: National Science Foundation, Agriculture, Ecosystems and Environment

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