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Rabbit-like rabbit liver organoid. Credit: Dr Egi Kardia CSIRO
Australia has been locked in a battle to control rabbits since the 1950s. Rabbits cause huge damage to our environment. They compete with native species, overgraze native plants and cause erosion. High rabbit numbers can also help sustain large populations of other invasive species, notably feral cats and foxes.
A recent global assessment report by the United Nations found invasive alien species such as rabbits are the leading cause of biodiversity loss and species extinction in Australia. Keeping their numbers low over long periods of time is essential for Australia’s biodiversity and rural industries.
The best way to control rabbits across the landscape is to use self-sustaining biological control (biocontrol) methods. Biocontrol uses biological agents such as natural enemies or diseases to manage pest species.
Australia’s rabbit control programs
European rabbits infest two-thirds of Australia and are a serious threat to our native species.
Rabbits are expensive to control using poisons, burrow fumigation, shooting and trapping. What’s more, these methods are ineffective in the long term and at large scales. Rabbits are estimated to cost on average $216 million a year in lost agricultural productivity. They are our most costly invasive alien species for agriculture.
Close up of rabbit liver organoid cells. Virus proteins in green. Cell nuclei in blue. Liver cells in red. Credit: Dr Egi Kardia CSIRO
Australia’s rabbit biocontrol programs employed the Myxoma virus in 1950 and the rabbit hemorrhagic disease virus (RHDV, also known as rabbit calicivirus) in 1995. They have been extremely successful in drastically reducing pest rabbit numbers in Australia at scale. These two viruses are host specific. This means they attack only rabbits and, in some cases, closely related species such as hares.
These viruses have saved Australian agriculture over $70 billion. It makes them our greatest invasive alien species management success story.
However, there is no status quo in rabbit biocontrol: the viruses and rabbits constantly co-evolve. Surviving rabbits develop resistance and varying levels of immunity, leading to numbers bouncing back.
Current research aims to help the RHDV stay ahead in the co-evolutionary arms race with its rabbit host. This will protect the gains made by the past successful biocontrol initiatives and keep rabbit numbers below the damage threshold.
In a major breakthrough, our scientists have now developed new ways to grow and study rabbit biocontrol viruses outside of live animals. They’ve developed organoid culture systems based on liver cells from already culled wild rabbits and hares around Canberra. Organoids are tiny 3D cellular structures that mimic the cells of the organ they come from. They act very similarly to the organ so represent a life-like model. The findings are published in the Journal of General Virology.
Close up of rabbit liver organoid cells. Virus genetic material in green. Cell nuclei in blue. Credit: Dr Egi Kardia CSIRO
Scientists have been trying to achieve this for 40 years, and this is the first time they’ve been able to grow these viruses in a cell culture outside of an animal. Our researchers found that two types of Rabbit Hemorrhagic Disease Virus (RHDV) replicated successfully in the organoids. The first is known to only infect rabbits. The second can infect rabbits as well as hares.
Both viruses replicated successfully in rabbit organoids, but only the virus known to also infect hares replicated in the hare organoids. The team also made organoids derived from cat and mouse livers. However, RHDV did not replicate in these. This finding shows these viruses are very host specific only to lagomorphs (rabbits and hares). We also know that these viruses are not zoonotic so pose no risk to humans. Their research paper is available to view publicly.
Until now, studying these viruses has been difficult due to the lack of a reliable cell culture system. This new model will make research into viruses like these easier and faster. It will also reduce the need for testing on live animals.
The establishment of this culture system for rabbit viruses is significant. It will allow scientists to study the viruses in a controlled environment. This could help further our understanding of the diseases they cause and develop further biocontrol strategies.
More information: Egi Kardia et al, Hepatobiliary organoids derived from leporids support the replication of hepatotropic lagoviruses, Journal of General Virology (2023). DOI: 10.1099/jgv.0.001874
Insectivorous bats were found to suppress pests and reduce damage to rice crops in a study in Assam.
Insectivorous bats are generalist eaters; their diet includes a variety of pests, including those that damage crops.
Greater legal protection and funding for studies focusing on bat ecology would go a long way in helping understand and conserve the mammals.
Findings from a recent study conducted in Assam suggest that bats can have a positive impact on rice ecosystems. In the study, conducted over the Sali (winter) rice season of 2019, insectivorous bats were found to help reduce damage to rice crops by suppressing pests, thus protecting yield.
“There is no doubt that bats are incredibly important to agricultural landscapes. I hope that in the next few years we can get to a more definite answer as to exactly what their economic value is in Indian agriculture,” says Iqbal Bhalla, one of the researchers of the study that was published in the journal Agriculture, Ecosystems & Environment.
The Integrated Pest Management (IPM) programme was introduced in India in 1992, to reduce dependence on pesticides in agriculture. It combines the use of biological, cultural and chemical practices to control insect pests in agricultural production. Under the programme, natural predators such as fish, frogs, parasitoids and ducks have been used to control agricultural pests over the years.
In the last decade, bats for pest management have gained traction. Insectivorous bats are generalist eaters. Their diet includes a variety of pests, including those that damage crops. They can thus suppress resident pest populations, and act as a buffer against sudden outbreaks or the invasion of new pest species. “Their diet is also complemented by their high mobility. It allows them to change foraging grounds and survive on different prey when crop pests are not available. They can also help limit the spread of disease by reducing the number of disease vectors, such as mosquitoes and flies,” says Hitesh Jha, an independent wildlife biologist studying bats in Maharashtra.
Bats roost in the bamboo poles used to build houses in Assam. The researchers say they believe that it may be helping sustain bat populations. Photo by Iqbal Bhalla.
“In my experience, most farmers have an incredibly intuitive understanding of agricultural ecosystems. Every farmer I spoke to was well aware of the value of birds and bats as pest control agents. An interesting method of biological pest control I saw in the fields of Assam is the placement of thin branches into the ground at regular intervals in rice fields. These branches provided insectivorous birds (mainly swallows) places to rest, thereby encouraging them to go further into the field and catch insects,” says Bhalla.
Bats limit damage by pests
The recent study was conducted in the rice fields of Puthimari, a village in the Sonitpur district of Assam. Rice is a major crop in the state, grown on 2.54 million hectares of land.
“I chose rice because of its economic importance to the country. I wanted an area where rice was grown in conditions similar to others in the state, to make generalisations more accurate,” says Bhalla.
The particular location was chosen because the fields to the east of the village were large and uninterrupted and offered sites that were identical in management strategy, set approximately 100m from each other. The study accounted for the insectivorous bat community as a whole, in part because the researchers didn’t know which species they would find on field, and in part because their study was based on acoustic analyses and lacked a library that matched bat calls to specific species. “We could only classify the bat calls we recorded to what is known as an acoustic sonotype. That being said, we know for a fact that we recorded the greater false vampire bat, the greater Asiatic yellow bat, and the lesser Asiatic yellow bat,” says Bhalla.
Using six sets of paired experimental and control plots (of which five were analysed), where bats were selectively excluded from the experimental plots, the researchers collected two measures of plant damage and one measure of total yield to assess the impact of bat presence on the crop. In parallel, bat activity at the six sites was recorded over the rice growing season using passive acoustic recorders.
The results show that the exclusion of insectivorous bats causes an increase in the degree of defoliation in the rice crop. The general trend in activity levels and the significant difference in plant damage also strongly suggests that bats suppress pest action in rice fields. “They do limit damage done by pests to the rice crop, though we could not prove that they improve yield outright,” says Bhalla.
The exclusion experiment. Plant damage and yield, to understand the impact of the presence of bats, as well as bat activity using passive acoustic recorders were studied at the experiment sites in Puthimari village. Photo by Iqbal Bhalla.
Habitat protection around rice fields important
There are over 1,400 bat species worldwide, of which over a third are threatened, according to the International Union for Conservation of Nature (IUCN). Habitat loss is one of the main reasons for a decline in bat populations.
Given that rice fields are ‘open’ habitats — they have no trees for bats to roost in, or along which bats can hunt — most bats prefer hunting only near the edges in forested and semi-forested areas around rice fields. Destruction to these areas can directly impact bats. “It’s also worth noting that only two of India’s 128 bat species, Wroughton’s free-tailed bat and Salim Ali’s fruit bat, are protected by law,” says Jha.
Farmers planting seedlings in a paddy field in Assam. Photo by ঈশান জ্যোতি বৰা/Wikimedia Commons.
Greater legal protection and funding for studies focusing on bat ecology would go a long way in understanding and conserving these mammals. Especially, since researchers of the study also believe that the findings are very likely to be similar across crop types — that bats are ‘lunarphobic’ (less active on bright, moonlit nights because of predators like owls), that bats track insects (and pest insects), bat population growth patterns (which often follows crop maturity), that urban areas disturb bats, and that forested and semi-forested areas are needed to sustain and grow bat populations.
“Although, bats can be extremely specialised to specific habitat conditions. If we moved from a seasonal crop like rice to a perennial agroforestry coffee plantation, we are likely to see very different patterns in bat behaviour,” says Bhalla.
Banner image: Greater false vampire bat. A study in Assam recorded the greater false vampire bat on rice fields at the study site. Photo Jenis Patel/Wikimedia Commons.
Several hundred farmers in the rural areas of Kalimpong district of West Bengal need to protect their crops from peacocks. In several parts of Kalimpong, where rice, chilies, vegetables, millet, flowers and fruits grow in abundance, peacocks – the national bird – have come to be a headache for most farmers, many of whom have incurred losses and shifted to crops like maize that do not attract the birds as much.
Others have taken to building temporary huts in the fields where they spend the night to protect the crops from peacocks and peahens who usually come to the farms in the early hours of the morning.
The growers cannot harm these birds, as they are protected by law.
Researchers at the University of Adelaide have released their findings about the potential effectiveness of gene drive technology to control invasive mice.
Key points:
A South Australian research team identifies new technology it hopes will eventually curb mice numbers
Co-author Luke Gierus says the technology is the first feasible genetic biocontrol tool for invasive mammals
Researchers believe the technology can be developed to work against other invasive pests
The technology — named t-CRISPR — uses sophisticated computer modelling on laboratory mice.
DNA technology is used to make alterations to a female fertility gene and, once the population is saturated with the genetic modification, the females that are generated will be infertile.
Research paper co-first author and post-graduate student Luke Gierus said the technology was the first genetic biological control tool for invasive animals.
“So we can do an initial seeding of a couple hundred mice and that will be enough, in theory, to spread and eradicate an entire population,” he said.
“We’ve done some modelling in this paper and we’ve shown using this system we can release 256 mice into a population of 200,000 on an island and that would eradicate those 200,000 in about 25 years.”
Paper co-author Luke Gierus says the technology has a long way to go but signs are promising.(Supplied: Luke Gierus)
The team has been undertaking the research for five years.
Mr Gierus said the next step would be to continue testing in laboratories before releasing mice onto islands where the team could safely monitor the effects.
He said the method was far more humane than other methods, such as baiting.
“It’s potentially a new tool that can either be used alongside the current technology or by itself,” Mr Gierus said.
“This is quite a revolutionary technology that gives us another way to try and control and suppress mice.”
Invasive mouse species have caused millions of dollars in damages to crops in recent years.(ABC News Video)
Technology welcomed
CSIRO research officer and mouse expert Steve Henry said wiping out mice from agricultural systems would be a wonderful outcome but he could not see it happening any time soon.
“The farming community are fantastic in terms of their willingness to adopt new ideas, so while it’s really important to do this research, the time frame is long and we need to make sure we don’t say we have a solution that’s just around the corner.”
But Mr Henry believed the technology would be welcomed with open arms when it did arrive.
CSIRO researcher Steve Henry says farmers are keen on innovative solutions.(ABC News: Alice Kenney)
“While we need to be focusing on the stuff that we can use to control mice now, we also need to be looking outside of the box in terms of these new technologies … into the future,” he said.
Mr Henry said that while he did not have extensive knowledge about the technology, it was exciting.
“The other thing that is really cool is you can make it so it doesn’t affect native rodent species as well,” he said.
Farmers group welcomes research
Grain Producers South Australia chief executive officer Brad Perry said introduced mouse species could severely damage crops and equipment, and recent plagues had been destructive.
“When it comes to pests and diseases in grain and agriculture more broadly, we need to be innovative and think outside the square on prevention measures,” Mr Perry said.
He said technology such as this could help farmers save money in the long run.
Invasive mice species can have a devastating impact on crops.(Supplied: Michael Vincent)
“Grain producers currently manage populations by minimising the food source at harvest, and if populations require [it] zinc phosphide baits are used,” Mr Perry said.
“However, using baits adds to input costs, it is not always readily available and there are limited windows to when this is effective.”
Mr Perry said many farmers would be keen to see the technology in the near future.
“We are supportive of additional tools that help reduce introduced mouse populations — particularly when it involves local world-leading research at the University of Adelaide — which is targeted, reduces inputs and is sustainable.”
Bats help keep forests growing. Without bats to hold their populations in check, insects that munch on tree seedlings go wild, doing three to nine times more damage than when bats are on the scene. That’s according to a new study from the University of Illinois. The article, “Bats reduce insect density and defoliation in temperate forests: an exclusion experiment,” is published inEcology.
“A lot of folks associate bats with caves. But as it turns out, the habitat you could really associate with almost every bat species in North America is forest. And this is true globally. Forests are just really important to bats,” says Joy O’Keefe, study co-author and assistant professor and wildlife extension specialist in the Department of Natural Resources and Environmental Sciences at Illinois. “We wanted to ask the question: Are bats important to forests? And in this study, we’ve demonstrated they are.”
Other researchers have demonstrated bats’ insect-control services in crop fields and tropical forest systems, but no one has shown their benefits in temperate forests until now.
“It’s especially important for us to learn how bats affect forests, given that bats are declining due to diseases like white-nose syndrome or collisions with wind turbines. This type of work can reveal the long-term consequences of bat declines,” says Elizabeth Beilke, postdoctoral researcher and lead author on the study.
The research team built giant mesh-enclosed structures in an Indiana forest to exclude the eight bat species that frequent the area, including two federally threatened or endangered species. The mesh openings were large enough to allow insects free movement in and out, but not flying bats. Every morning and evening for three summers, Beilke opened and closed the mesh sides and tops of the structures to ensure birds had daytime access to the plots. That way, she could be sure she was isolating the impacts of bats.
Beilke then measured the number of insects on oak and hickory seedlings in the forest understory, as well as the amount of defoliation per seedling. Because she erected an equal number of box frames without mesh, Beilke was able to compare insect density and defoliation with and without bats.
Overall, the researchers found three times as many insects and five times more defoliation on the seedlings when bats were excluded than in control plots that allowed bats in each night. When analyzed separately, oaks experienced nine times more defoliation and hickories three times more without bats.
“We know from other research that oaks and hickories are ecologically important, with acorns and hickory nuts providing food sources for wildlife and the trees acting as hosts to native insects. Bats use both oaks and hickories as roosts, and now we see they may be using them as sources of prey insects, as well. Our data suggest bats and oaks have a mutually beneficial relationship,” Beilke says.
While insect pressure was intense in plots without bat predation, the seedlings didn’t succumb to their injuries. But the researchers say long-term bat declines could prove fatal for the baby trees.
“We were observing sublethal levels of defoliation, but we know defoliation makes seedlings more vulnerable to death from other factors such as drought or fungal diseases. It would be hard to track the fate of these trees over 90 years, but I think a natural next step is to examine the impact of persistent low levels of defoliation on these seedlings,” Beilke says. “To what extent does repeated defoliation reduce their competitive ability and contribute to oak declines?”
The researchers point out that birds, many of which share the same insect diets as bats, are also declining. While they specifically sought to isolate bats’ impact on forest trees, the researchers are confident insect density and defoliation rates would have been higher if they had excluded both birds and bats in their study. In fact, similar exclusion studies focusing on birds failed to account for bats in their study designs, leaving mesh enclosures up all night.
“When we were initially working on the proposal for this research, we looked at 37 different bird exclusion studies, across agriculture and forest systems. We found nearly all of them had made this mistake. Most of them had not opened or removed their treatment plots to bats,” Beilke says.
In other words, before Beilke’s study, birds were getting at least partial credit for work bats were doing in the shadows.
Clearly, both types of winged predators are important for forest health in temperate systems. And, according to O’Keefe, that makes these studies even more critical to inform forest management.
“I think it’s important to stress the value of this type of experimental work with bats, to really try to dig into what their ecosystem services are in a deliberate manner. While we can probably extrapolate out and say bats are important in other types of forest, I wouldn’t discount the value of doing the same kind of work in other systems, especially if there are questions about certain insect or tree species and how bats affect them. So rather than extrapolating out across the board, let’s do the work to try to figure out how bats are benefiting plants,” she says. “And before they’re gone, hopefully.”
More information: Elizabeth A. Beilke et al, Bats reduce insect density and defoliation in temperate forests: An exclusion experiment, Ecology (2022). DOI: 10.1002/ecy.3903
Imagine a world where farms bear no crops, forests have no trees and nature exists without plants.
Not only will our world look incredibly different, but humanity would likely cease to exist altogether. Plants provide 98% of the air we breathe and 80% of the food we eat. That’s how much our lives depend on plants, yet we often overlook how vital they are.
Our global plant resources are under threat from pests and diseases. Once plant pests are established in an area, it becomes nearly impossible and extremely costly to eradicate them. This sets back global efforts to achieve the Sustainable Development Goals by curtailing our ability to provide food security for all, protect our environment and biodiversity for future generations, and to ensure that crops and plant products are traded safely to help boost economic growth.
Every year, we lose as much as 40% of global crop yields or around US$220 billion due to plant pests. In Africa alone, nearly US$10 billion worth of annual maize yield is lost due to fall armyworm, a dangerous transboundary pest that has now spread in more than 70 countries. Reducing this menace will help alleviate hunger of the type faced by some 828 million people around the world in 2021, according to the latest report of the UN’s Food and Agriculture Organization (FAO).
Climate change has increased pest incursions, particularly in new places where they had not been detected previously but have now thrived. Changing temperatures, humidity, light and wind are the second most important factors for pests to disperse, next to international travel and trade.
Invasive pests remain the main drivers of biodiversity loss. As the world becomes more globalized and interconnected, the increase in the movement of people and goods has been associated with the rise of the introduction and spread of plant pests across borders.
That is why global frameworks are crucial such as the International Plant Protection Convention (IPPC), an international treaty ratified by 184 countries which makes provisions for the protection and safeguarding of plants and facilitation of safe trade.
International Standards for Phytosanitary Measures—the gold standard in plant health—are in place for countries to adopt in their national legislation and import requirements. These standards range from pest surveillance, pest risk analysis, guidance for countries in developing pest eradication programs, national reporting of important pests, and more.
Global network of plant experts
Building a global community of plant health experts and advocates is essential. The IPPC Secretariat works with partners and donors to develop standards, facilitate countries’ adoption of the Convention and implementation of standards, and build the capacity of national plant protection organizations.
Guides, training materials and e-learning courses help these plant stewards effectively carry out their duties in safeguarding plants. Innovative tools such as the ePhyto allow countries to trade safely using digital phytosanitary certificates that make the trade in plants safer, faster and cheaper.
Raising global awareness and action among the wider public is also important. In 2020, we celebrated the International Year of Plant Health through 680 events held in 86 countries.
On May 12, 2022, the first International Day of Plant Health was declared following its adoption at the General Assembly of the United Nations in March. We thank the governments of Zambia and Finland as tireless champions in tabling the resolution at the Assembly, supported by FAO and the IPPC Secretariat.
The IPPC Secretariat and the Department for Environment, Food and Rural Affairs of the UK this week partnered to gather the world’s best plant health experts and advocates. The first and largest International Plant Health Conference being held in London aims to address new and emerging challenges such as climate change impact, the increase in international trade, the rapid loss of biodiversity and new pest pathways such as e-commerce. We will explore more efficient policies, structures and mechanisms at the national, regional and global levels.
Much work remains in protecting our plants. We need to be cautious when bringing plants and plant products when traveling as these could carry plant pests and diseases. Likewise, we should be aware that buying plants and plant products online should come with phytosanitary certificates that attest they meet phytosanitary import requirements.
E-commerce is an emerging pathway for the introduction and spread of plant pests. Online purchases cross international borders through mail or express freight systems via air freight or sea containers. These purchases often include but are not limited to, ornamental plants, soil from imported plants, untreated wood packaging materials such as pallets and crates and even novelty items such as seed-infused “plantable bookmarks.”
We call on governments, legislators, policymakers and donors to invest in research, outreach and in building the capacity of national plant protection organizations, and to strengthen pest monitoring and early warning systems.
We need all industry actors and government partners to adhere to international plant health standards to mutually protect our plants, food supplies and our economies.
When we protect plants, we protect our health, our environment, our livelihoods and our lives.
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 ofBatesian 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,” saysDanilo 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.”
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
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.
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.”
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
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.
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.”
Global Plant Protection News 