How do bats survive their own coronaviruses?

How do bats survive their own coronaviruses?

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How do bats survive their own coronaviruses (without showing any symptoms)?

Or, more generically, how can viruses keep reproducing inside healthy carriers without inducing any pathogenic effect?

Are coronaviruses able to replicate themselves without harming bats, or maybe these viruses are just latent like herpesviruses in humans?

Related question: Why are bats the source of dangerous coronavirus pandemics?

It's common for the reservoir host of a zoonotic virus to be tolerant of it. MERS coronavirus appears to cause mild or no disease in dromedary camels ( source ), but kills about 35% of confirmed infected humans. ( CDC ) Sin Nombre hantavirus seems to be mild in the deer mice that spread it, despite ~36% fatality rate in humans. ( source ) Mosquitoes are efficient vectors for flaviviruses like dengue and zika in part because they have adaptations we lack that protect them from the virus. ( source ) Also, human communities are host to several viruses: about 90% of people have a herpesvirus infection ( source ) with similar numbers for polyomaviruses. ( source ) Very few of these infected individuals show symptoms.
The wide prevalence of these asymptomatic infections shows that the virus is successful when it can replicate while the host remains healthy. In general, virus reproduction kills cells, and when cells die faster than the host can replace them, this causes symptoms up to and including death. The host's immune system supresses virus activity, and a virus that can't evolve ways to avoid immune supression will be wiped out. But if the virus gets so good at avoiding the immune system, it will kill the host, which is bad for the virus. So both host and virus tend to evolve to a point where the immune system wins most, but not all of the time. There is a lot more to it, but I'll stop here.

In conclusion, we don't really need to look for special properties of bats to explain their tolerance of coronaviruses, even though, as iayork points out, there are reasons to expect bats might be more resistant.

It's been tentatively proposed that bats are often unusually able to tolerate long-term infection with a wide range of viruses (though this hasn't been formally shown to be true). A specific cause for this (possible) phenomenon isn't known, but many possible explanations have been put forward. It's likely that if it's true, there's no single cause but rather a combination of multiple causes to add together.

Bats have an array of unique life history characteristics that not only allow them to be particularly good reservoirs for viruses that are highly pathogenic in other species, but also appear to have shaped their immune systems. Although research on bat antiviral immunity has focused on only a few species to date, at the genomic level, selection on genes is concentrated on the innate immune system across both suborders of bats. However, while these studies have provided a rich source of hypotheses, the majority remain to be tested at the functional level and many questions remain that cannot be answered from comparative genome studies. Experimental studies to date have demonstrated some functional differences between bat species, with the common emerging theme that the overall antiviral response appears to converge on a lower inflammatory profile, with tight regulation of the cytokine and inflammatory response key to clearing viral infection without the pathological outcomes typically associated with infection.

--Going to Bat(s) for Studies of Disease Tolerance

Tasmanian devils may survive their own pandemic

Tasmanian Devil. Credit: Alecia Carter

Amid the global COVID-19 crisis, there is some good news about a wildlife pandemic—which may also help scientists better understand how other emerging diseases evolve.

Researchers have found strong evidence that a transmissible cancer that has decimated Tasmanian devil populations likely won't spell their doom.

For the first time, a research team led by Washington State University biologist Andrew Storfer employed genomic tools of phylodynamics, typically used to track viruses, such as influenza and SARS-CoV-2 , to trace the Tasmanian devil facial tumor disease. The approach they pioneered has opened the door for application to other genetically complex pathogens.

The study, published in the journal Science on Dec. 10, indicated that the devils' pandemic is shifting from an emerging disease to an endemic one—meaning the disease spread is slowing to the point that each infected devil is infecting only one additional animal or less.

"It is cautiously optimistic good news," said Storfer. "I think we're going to see continued survival of devils at lower numbers and densities than original population sizes, but extinction seems really unlikely even though it was predicted a decade ago."

A fight at a Tasmanian devil carcass. Credit: Rodrigo Hamede

Since it was first identified in 1996, Tasmanian devil facial tumor disease has reduced populations of the iconic marsupial by 80%. The devils spread the infection when they fight and bite each other on the face. The disease is still largely fatal to Tasmanian devils who contract it, but it appears to be reaching an equilibrium, according to this study which confirms evidence from previous field studies. The authors say this new evidence means managers should re-consider the practice of releasing captive-bred devils into the wild.

"Active management may not be necessary and could actually be harmful," Storfer said. "It looks like the devil populations are naturally evolving to tolerate and possibly even resist the cancer. By introducing a whole bunch of genetically naïve individuals, they could breed with the wild individuals, basically mix up the gene pool and make it less well-adapted."

The disease-naïve, captive-bred individuals could also increase transmission of the disease among different groups of devils.

A running Tasmanian devil. Credit: Alecia Carter

Researchers have relied on field studies and modeling to try to understand the spread of the Tasmanian Devil facial tumor disease, but this is the first time that phylodynamics has been used successfully to trace the transmissible cancer.

Phylodynamics employs genetic sequencing to investigate evolutionary relationships among pathogen lineages to understand and predict how a disease spreads across a population. This method has been used to trace the spread of viruses, including influenza and SARS-CoV-2, which accumulate mutations in their genomes at a relatively fast rate.

The Tasmanian devil facial tumor disease is much more genetically complex than a virus, however. Since the disease is a type of cancer, derived from the animals' own cells, the genes that need to be traced are essentially the Tasmanian devils' genes, of which there are thousands more than those of a typical viral pathogen.

In this study, the researchers screened more than 11,000 genes from tumor samples to find genes that changed in a "clock-like" manner, showing mutations that were accumulating rapidly. They then identified 28 genes representing more than 430,000 base pairs, the fundamental units of DNA.

In comparison, the genome of SARS-CoV-2, the virus that causes COVID-19, has 29,000 base pairs.

The breakthrough in using this method took months of pain-staking computational work, which Storfer credits to his doctoral student, Austin Patton, a recent WSU Ph.D. graduate who is now a post-doctoral fellow at University of California, Berkeley.

"One of the most exciting advances this study presents is the opportunity to apply these types of approaches to virtually any pathogen," said Patton. "It opens the door to using the kind of methods that have been shown to be so important in the study of viruses to a whole new suite of pathogens that impact humans as well as wildlife."

Can scientists help insects survive their fatal attraction to light at night?

Each summer, on bridges across the world, mayfly massacres occur. First, warm weather prompts the transformation of the insects’ aquatic larvae. Within hours, the short-lived, flying adults pop out of streams, rivers, and lakes, eager to mate and lay eggs by the millions.

But bridges illuminated with artificial light can lure the newly emerged adults away from the water to a futile death before breeding. Others, fooled by the sheen of reflective pavement, drop their eggs on the bridge road instead of the water. Because mayflies control the growth of algae and are food for fish, the fate of these humble insects may reverberate through ecosystems, says Ádám Egri, a biological physicist at the Centre for Ecological Research in Budapest, Hungary, who is working to save endangered mayflies there.

Mayflies aren’t alone in their fatal attraction to what researchers refer to as ALAN: artificial light at night. Studies from around the globe are finding worrisome impacts on insect mating and abundance, says Stéphanie Vaz, an entomologist at the Federal University of Rio de Janeiro’s main campus. In the past year, researchers have published the first experimental and regional studies of the problem, and in March, Insect Conservation and Diversity devoted a special issue to the topic.

Some researchers think brighter nights may be a factor in recently documented insect declines, says Stephen Ferguson, a physiological ecologist at the College of Wooster. With insect numbers dropping by 80% in some places and 40% of insect species headed for extinction by some estimates, “Some researchers have started to make more noise about the ‘insect apocalypse,’” Ferguson says. “ALAN is almost certainly one of the drivers.”

Even as they begin to raise the alarm, scientists are pointing to simple solutions. Egri, for example, has found that mounting bright lights low on the sides of bridges keeps the mayflies close to the water. But researchers are “still at the very beginning of the story of global, ecologically friendly artificial lighting,” he says.

Many insects and other animals are drawn to light because they depend on the Moon or Sun for navigation, Ferguson says. And light at night is increasing by an average of 2% to 6% and up to 40% per year in remote places, according to ALAN researcher Franz Hölker at the Leibniz Institute of Freshwater Ecology and Inland Fisheries, who calculated this estimate using satellite, energy use, and other data. Cities are using more light-emitting diodes, whose blue light appears brighter than the yellow glow of sodium vapor streetlights.

Even dark areas are no longer very dark. “Protected areas are not able to buffer these light intensities as we thought,” Vaz says. On Moon-less nights, artificial sky glow now exceeds the combined light of stars and other natural sources on 22% of the globe’s total land, with biodiversity hot spots disproportionately affected, Brett Seymoure, a behavioral ecologist at Washington University in St. Louis, and his colleagues report in the preprint elibrary SSRN.

Given the many other factors also hurting insects, such as habitat degradation and climate change, linking light to species’ declines is challenging. “It is a very understudied field,” Hölker says. But scattered studies suggest the impact may be powerful. He and others have calculated that Germany’s 9 million streetlights attract about 1 billion insects a night, many of which die or are killed by bats and other predators. Researchers have estimated that at least one-third of the insects swarming around artificial lights die of exhaustion or are eaten by predators.

In Grand Teton National Park, a new system of dimmer, reddish lights attracts fewer insects—and lets visitors see the stars.

One recent study underscores the magnitude of the effect. On the night of 27 July 2019, the glow of Las Vegas lights lured massive numbers of migrating grasshoppers into the air above the city, according to a 31 March paper in Biology Letters. The clouds of grasshoppers were visible on weather radar by estimating numbers of insects seen on radar before, during, and after the swarm, Elske Tielens, an ecologist at the University of Oklahoma, Oklahoma City, and her colleagues calculated that at its peak, the swarm weighed 30.2 tons and contained 48 million grasshoppers.

There were “more grasshoppers in the air on that single July night than human visitors to Las Vegas in a whole year,” Tielens says. “This is probably happening on smaller scales in many places, and with many more insects,” Ferguson adds.

In the Netherlands, a consortium of universities, nonprofit organizations, industry, and government is exploring light’s effects on local ecosystems through the Light on Nature project. It set up long-term experiments in seven sets of plots in dark areas. The researchers lit up some plots with lights of different colors and monitored bat and insect communities. Between 2012 and 2016, moth numbers remained steady in dark plots but decreased 14% in lighted areas, Roy van Grunsven, an entomologist at Dutch Butterfly Conservation, and colleagues reported in June 2020 in Current Biology.

“This study represents the only published experimental evidence to date” about ALAN’s long-term effects, says Douglas Boyes, an entomologist at the UK Centre for Ecology and Hydrology in Wallingford. “The bottom line is that moths are being bombarded with unnatural night conditions that their sensory systems are not adapted for,” Seymoure adds.

Most of the research on artificial light so far has taken place in temperate climates. But Vaz’s modeling studies point to light pollution as a possible cause for a decline in firefly diversity in Brazil’s Atlantic Forest. And Jessica Deichmann, an applied ecologist at the Smithsonian Conservation Biology Institute, documented what happens when electric lights were first turned on in a remote tropical forest in Peru. “I’ve witnessed firsthand the truly massive storm clouds of insects drawn to lights when they are first installed, and this sight is hard to forget,” she says. Most of the insects, particularly flying ants and flies, die of exhaustion or are eaten.

She worries the nightly tolls will curtail pollination and other ecosystem services provided by these species. So, like more and more ALAN researchers, she is seeking solutions. Her team set up experimental plots in the forest lit by lights of different colors and discovered amber lights attracted 60% fewer insects than white light.

But what’s good for some flying insects may be bad for others, as Tufts University graduate student Avalon Owens described in January at a virtual meeting of the Society for Integrative and Comparative Biology. Owens evaluated how fireflies and other flying insects reacted to red, blue, and amber light in Kellettville, Pennsylvania, a rural area with little light pollution and so many Photinus carolinus fireflies that the town hosts an annual firefly festival. Observing fireflies in the wild, “I found red light is ‘best,’ and amber is ‘worst’ for interfering with courtship,” she says.

In the lab, she found that in amber light, “females go almost completely dark,” leaving males no way to find them, she and her colleagues reported in the special issue.

Egri and his colleagues, too, tested the impact of color, hanging beacons of different hues low on a bridge, then photographing and counting mayflies. Blue lights, being even brighter than the yellowish road lights, kept more insects close to the water. For two springs now, blue beacons installed on the Tahitótfalu bridge in northern Hungary have shone for 3 hours past sunset, while lights on the roadway are dimmed. This seems to work, Egri says. “No mayflies left the river.”

Elsewhere, dimmer, redder lights are being tested, including at a visitor center in Grand Teton National Park. But Egri says his own effort and others “are still too little.” Deichmann agrees that more ambitious measures are needed. For the sake of insects and ecosystems, “It is absolutely essential to ensure substantial areas of our planet remain dark forever.”

MONACA, Pa. — Bats are finicky about their real estate.

Their ideal abode is 15-20 feet off the ground, in direct sunlight for eight hours a day, close to water, and far from predators and artificial light.

So when Cassandra Miller-Butterworth and Stephanie Cabarcas-Petroski’s biology students and Jim Hendrickson and Sherry Kratsas’ engineering students collaborated to research, design and build bat houses for class last spring, they found only two spots on Penn State Beaver’s campus that were just right — near the softball field and near the pond — and installed traditional houses there on Earth Day.

Four other bat houses — all modern designs of the engineering students — went unhung, until now. Thanks to the efforts of Kratsas, Cranberry Township has agreed to place the remaining bat houses throughout its parks system this summer.

Miller-Butterworth is thrilled, because more bat houses could equal more bats, and more bats certainly equals a better-balanced ecology.

“I love bats,” Miller-Butterworth said. “Bats are my passion.”

Farmer’s best friend

In popular culture, bats are ugly, winged things that come out on Halloween and can instantly morph into blood-drinking vampires. In reality, they’re useful little creatures that come out on summer nights to gobble up all of the nuisance insects we don’t want in our yards or on our crops.

In fact, bats can eat their body weight in insects in a single night and, one study estimates, save farmers $23 billion per year in pesticides. Which is why the spread of white-nose syndrome — the disease that has killed more than 7 million bats since 2006 — is so terrifying.

Little brown bats, the kind that populate the area and that Miller-Butterworth studies, have been particularly hard hit. In some caves, the mortality rate has reached 90 percent.

This is how it happens: In the winter, little brown bats seek out cold, dry caves where they can lower their body temperatures for a season of hibernation.

Unfortunately, the fungus that causes white-nose syndrome also likes it cold and dry, and it takes advantage of the bats’ vulnerable state, infecting wings and causing them to wake multiple times from their slumber. Each time they wake, they use up valuable fat reserves.

“Eventually,” Miller-Butterworth said, “they die of starvation and dehydration.”

Those bats that manage to survive the winter appear to have some immunity to the disease, but the situation remains dire because they often first need to be nursed back to health.

“It’s not practical to do that with hundreds of thousands of bats,” Miller-Butterworth said.

And those that do survive will have a difficult time repopulating the species. Bats only give birth to one pup a summer, and many pups don’t survive their first year.

The fallout of all of this is, without an answer to white-nose syndrome, little brown bats could be extinct in the next 15 to 20 years.

So will six bat houses in two counties really help save the species?

The houses offer female bats safe places to roost with their fragile pups. And the very act of planning and building the houses offered students a close-up view of the bats’ ecological importance. The more people who understand that importance, the better chance scientists like Miller-Butterworth have of helping the population.

But first, the bats will have to take up residence in the houses. Last summer, both houses on campus remained empty, but Miller-Butterworth remains optimistic. Bats often take a year or two to decide on the right real estate. (Remember, they’re finicky.)

And, if bats do come to Penn State Beaver, Miller-Butterworth will immediately begin working on another project: bat cams.

“It’s my dream is to have a bat cam on the website,” she said.

To read the papers Miller-Butterworth has published on little brown bats, click here and here.

Sunscreen Gene

A recent study in the journal eLife found that some fish, birds, amphibians, and reptiles have the genes to produce gadusol, a compound that can act as a sunscreen.

"Gadusol absorbs UV radiation, particularly UVB [ultraviolet B], and dissipates it as heat," study leader Taifo Mahmud, a professor of medicinal chemistry at Oregon State University, says via email.

The gadusol produced by zebrafish, a highly studied lab species, may even help scientists create a better sunscreen for people. (Also see "Do Sunscreens' Tiny Particles Harm Ocean Life in Big Ways?")

By transferring the zebrafish genes into yeast in the lab, researchers were able to test gadusol’s activity as a sunscreen and show that it can be produced commercially.

So, can I just rub a zebrafish on my face next time I forget my sunscreen?

A bit impractical, says Mahmud, but cod and sea urchin eggs—popular sushi ingredients—can contain the radiation-absorbing chemical.

So "you may have consumed gadusol without knowing it," he says.

That doesn’t mean it will act as a sunscreen in you, however—so for now, follow experts' advice for sun protection.

Tasmanian Devils May Survive Their Own Pandemic

(CN) — For the last decade, it appeared a contagious facial cancer would lead to the extinction of the Tasmanian devil, but new research suggests otherwise.

An unprecedented genetic analysis of the fatal devil facial tumor disease published in Science on Wednesday suggests not only that the marsupials are co-evolving with the disease, but that they may very well survive into the next century.

“Collectively, our group has a number of studies that have shown devils are evolving in response to the disease and the disease seems to be transitioning toward an endemic pathogen,” said Andrew Storfer, study author and biology professor at Washington State University. An expert in host-pathogen evolution, Storfer said became interested in the Tasmanian devil disease by chance while on sabbatical in Australia.

Discovered in 1996, devil facial tumor disease is a contagious cancer transmitted among Tasmanian devils through social biting. It is 100% fatal, killing hosts within 6 to 12 months. Since the disease emerged 25 years ago, it has decimated the devil population by 90%. Most expected the cancer to drive the rare mammals into extinction.

Instead, the analysis of 11,359 genes from 51 tumor samples collected between 2003 and 2018 reveals an intricate picture of co-evolution and adaptation. Phylodynamics — the study of how immune systems and evolution shape diseases — also helped scientists understand the genetic lineages of the Ebola virus and the novel coronavirus SARS-CoV-2, which causes Covid-19. Until now, phylodynamics was limited to studying simple viruses.

“One of our challenges was screening over 11,000 genes for evolution in a clocklike or regular pattern, which helps us generate an evolutionary tree that we can then use to estimate parameters like the growth in the population and the transmission rate over time,” Storfer said. “It took several months to do that, but the good news is now anyone can use that approach, in theory, to look at pathogens with larger genomes like bacteria and fungi.”

This analysis revealed 28 genes mutations following a clocklike pattern, allowing researchers to date the disease origination to between 1977 and 1987. In addition to identifying two different versions of the disease, researchers found both strains spread evenly and rapidly throughout the devils’ range.

Most surprising of all, this study provides evidence that rather than the death of the Tasmanian devils, the disease is becoming endemic to their life. The rate of infection appears to be decreasing, from each infected animal spreading the disease to 3.5 others down to a 1:1 infection rate.

More research is needed to confirm how devils have adapted to the disease, but two theories prevail: immunological adaptations, meaning the devils have become better at fighting the disease, and behavior.

In fact, research from the same lab published in the Proceedings of the Royal Society B on Tuesday suggests sick devils have started to self-isolate, thus reducing the spread of the disease.

“Ecological models show that under most scenarios, the devil should survive for at least 50 to 100 years,” Storfer said with cautious optimism. “This suggests that perhaps the best management strategy is actually just to let evolution run its course in the wild.”

Inside the Chinese lab poised to study world's most dangerous pathogens

Maximum-security biolab is part of plan to build network of BSL-4 facilities across China.

A laboratory in Wuhan is on the cusp of being cleared to work with the world’s most dangerous pathogens. The move is part of a plan to build between five and seven biosafety level-4 (BSL-4) labs across the Chinese mainland by 2025, and has generated much excitement, as well as some concerns.

Some scientists outside China worry about pathogens escaping, and the addition of a biological dimension to geopolitical tensions between China and other nations. But Chinese microbiologists are celebrating their entrance to the elite cadre empowered to wrestle with the world’s greatest biological threats.

“It will offer more opportunities for Chinese researchers, and our contribution on the BSL‑4-level pathogens will benefit the world,” says George Gao, director of the Chinese Academy of Sciences Key Laboratory of Pathogenic Microbiology and Immunology in Beijing. There are already two BSL-4 labs in Taiwan, but the National Bio-safety Laboratory, Wuhan, would be the first on the Chinese mainland.

The lab was certified as meeting the standards and criteria of BSL-4 by the China National Accreditation Service for Conformity Assessment (CNAS) in January. The CNAS examined the lab’s infrastructure, equipment and management, says a CNAS representative, paving the way for the Ministry of Health to give its approval. A representative from the ministry says it will move slowly and cautiously if the assessment goes smoothly, it could approve the laboratory by the end of June.

BSL-4 is the highest level of biocontainment: its criteria include filtering air and treating water and waste before they leave the laboratory, and stipulating that researchers change clothes and shower before and after using lab facilities. Such labs are often controversial. The first BSL-4 lab in Japan was built in 1981, but operated with lower-risk pathogens until 2015, when safety concerns were finally overcome.

The expansion of BSL-4-lab networks in the United States and Europe over the past 15 years — with more than a dozen now in operation or under construction in each region — also met with resistance, including questions about the need for so many facilities.

“ Viruses don’t know borders. ”

The Wuhan lab cost 300 million yuan (US$44 million), and to allay safety concerns it was built far above the flood plain and with the capacity to withstand a magnitude-7 earthquake, although the area has no history of strong earthquakes. It will focus on the control of emerging diseases, store purified viruses and act as a World Health Organization ‘reference laboratory’ linked to similar labs around the world. “It will be a key node in the global biosafety-lab network,” says lab director Yuan Zhiming.

The Chinese Academy of Sciences approved the construction of a BSL-4 laboratory in 2003, and the epidemic of SARS (severe acute respiratory syndrome) around the same time lent the project momentum. The lab was designed and constructed with French assistance as part of a 2004 cooperative agreement on the prevention and control of emerging infectious diseases. But the complexity of the project, China’s lack of experience, difficulty in maintaining funding and long government approval procedures meant that construction wasn’t finished until the end of 2014.

The lab’s first project will be to study the BSL-3 pathogen that causes Crimean–Congo haemorrhagic fever: a deadly tick-borne virus that affects livestock across the world, including in northwest China, and that can jump to people.

Future plans include studying the pathogen that causes SARS, which also doesn’t require a BSL-4 lab, before moving on to Ebola and the West African Lassa virus, which do. Some one million Chinese people work in Africa the country needs to be ready for any eventuality, says Yuan. “Viruses don’t know borders.”

Gao travelled to Sierra Leone during the recent Ebola outbreak, allowing his team to report the speed with which the virus mutated into new strains 1 . The Wuhan lab will give his group a chance to study how such viruses cause disease, and to develop treatments based on antibodies and small molecules, he says.

The opportunities for international collaboration, meanwhile, will aid the genetic analysis and epidemiology of emergent diseases. “The world is facing more new emerging viruses, and we need more contribution from China,” says Gao. In particular, the emergence of zoonotic viruses — those that jump to humans from animals, such as SARS or Ebola — is a concern, says Bruno Lina, director of the VirPath virology lab in Lyon, France.

Many staff from the Wuhan lab have been training at a BSL-4 lab in Lyon, which some scientists find reassuring. And the facility has already carried out a test-run using a low-risk virus.

But worries surround the Chinese lab, too. The SARS virus has escaped from high-level containment facilities in Beijing multiple times, notes Richard Ebright, a molecular biologist at Rutgers University in Piscataway, New Jersey. Tim Trevan, founder of CHROME Biosafety and Biosecurity Consulting in Damascus, Maryland, says that an open culture is important to keeping BSL-4 labs safe, and he questions how easy this will be in China, where society emphasizes hierarchy. “Diversity of viewpoint, flat structures where everyone feels free to speak up and openness of information are important,” he says.

Yuan says that he has worked to address this issue with staff. “We tell them the most important thing is that they report what they have or haven’t done,” he says. And the lab’s inter­national collaborations will increase openness. “Transparency is the basis of the lab,” he adds.

The plan to expand into a network heightens such concerns. One BSL-4 lab in Harbin is already awaiting accreditation the next two are expected to be in Beijing and Kunming, the latter focused on using monkey models to study disease.

Lina says that China’s size justifies this scale, and that the opportunity to combine BSL-4 research with an abundance of research monkeys — Chinese researchers face less red tape than those in the West when it comes to research on primates — could be powerful. “If you want to test vaccines or antivirals, you need a non-human primate model,” says Lina.

But Ebright is not convinced of the need for more than one BSL-4 lab in mainland China. He suspects that the expansion there is a reaction to the networks in the United States and Europe, which he says are also unwarranted. He adds that governments will assume that such excess capacity is for the potential development of bioweapons.

“These facilities are inherently dual use,” he says. The prospect of ramping up opportunities to inject monkeys with pathogens also worries, rather than excites, him: “They can run, they can scratch, they can bite.”

Trevan says China’s investment in a BSL-4 lab may, above all, be a way to prove to the world that the nation is competitive. “It is a big status symbol in biology,” he says, “whether it’s a need or not.”


Roosts provide bats with protection from weather and predators, and the type of roosting structure available affects foraging and mating strategies, seasonal movements, morphology, physiology, and population distribution. Bats in Greater Yellowstone use both natural habitats and man-made structures including bridges and abandoned mines.

Research suggests that that the thermal conditions in maternity roosts are important for the reproductive success of little brown bats. Young bats can maximize their growth rate, wean, and begin to fly and forage earlier because they are not using much energy to stay warm.

Bats are long-lived (10–30 years) and show fidelity to maternal roost sites where they have successfully raised young. For this reason, park managers try to exclude bats from the attics of park buildings. In 1904, the “type specimen” that describes the sub-species of little brown bat found in Yellowstone was collected from the Lake Hotel.

The presence of other bats in Yellowstone is probably restricted by the limited location of suitable roosts and/or the distribution of moths and beetles on which more specialized bats forage. It is likely that most western bat species migrate short distances from their summer roosts to their winter hibernating locations. However, bat activity has been documented during every month of the year, which suggests that multiple species may remain within Yellowstone over winter. Some species migrate long distances to areas where temperature and insect populations remain high enough for continued activity. These species usually do not hibernate. In Greater Yellowstone, the hoary bat likely migrates south for the winter.

Caterpillars turn anti-predator defense against sticky toxic plants

A moth caterpillar has evolved to use acids, usually sprayed at predators as a deterrent, to disarm the defenses of their food plants, according to a study publishing July 10 in the open-access journal PLOS ONE by David Dussourd from the University of Central Arkansas and colleagues.

Some plants such as poinsettia (Euphorbia pulcherrima) produce and store latex in specialized canals within their leaves, which can gum up and poison herbivorous insects that try to eat them. To get around this defense, larvae of the notodontid moth Theroa zethus bathe the leaf stem in an acidic secretion produced from a gland on the underside of their head, which prevents the flow of latex. To investigate this unusual strategy, the researchers filmed the caterpillar feeding, analyzed the creatures' acidic secretions, and investigated the effect of the acid at the cellular level.

They found that the caterpillar's secretion is a mixture of formic and butyric acids. Histological analysis showed that the secretion physically deforms plant cell walls. Video recordings documented that before applying the acid, the caterpillars use their mandibles to scrape at and compress the leaf stem. Artificially replicating these behaviors in the laboratory, using sandpaper and binder clips, also prevented latex flow from the leaves, confirming that the caterpillars' behaviors play a part in disarming the plant's defenses.

The team observed compression behaviors in six other species of notodontid moth which eat plants lacking latex canals, but only Theroa zethus used acid. The authors suggest that as the species evolved to feed on toxic plants, the caterpillars co-opted a pre-evolved anti-predator deterrent to help reduce the flow of latex and make their meal more palatable and less dangerous.

Dussourd adds: "To understand if a plant is vulnerable to insect feeding, one needs to consider not just the defenses of the plant, but also the capabilities of the insect. In this study, a caterpillar deactivates the latex defense of poinsettia by secreting acid from its anti-predator gland. The caterpillar facilitates acid penetration by scraping the plant surface, then compresses the plant to rupture the latex canals internally. The combination of behavioral manipulation and acid secretion allows the caterpillar to disarm the plant often without contacting any latex exudate."

Indiana bat

Who knew hibernating was so tiring? One bat yawns in a cluster of Indiana bats in Wyandotte Cave, Indiana. Photo by R. Andrew King, U.S. Fish and Wildlife Service.

First found in Southern Indiana’s Wyandotte Cave in the early 1900s, the Indiana bat is quite small, weighing only a quarter of an ounce (about the weight of three pennies). Even though it’s small, this species can eat up to half its body weight in insects each night, providing vital pest control. The Indiana bat’s scientific name is Myotis sodalis, and it’s an accurate description of this social species. Myotis means “mouse ear” and refers to the relatively small, mouse-like ears of the bats, and sodalis is the Latin word for “companion.” In the winter, Indiana bats hibernate in large numbers in caves (and occasionally abandoned mines) with the biggest colony supporting 20,000-50,000 bats! While found throughout the Eastern United States, more than half of their population hibernates in the caves in Southern Indiana.

Do your part to help bats by building a bat house. These tiny structures are a win for both bats and humans. They can hold up to 100 bats, providing them with much need roosts while the bats keep the pests at bay around your house.