Wednesday, 8 July 2020

To protect threatened beetle, entomologists hope new colony takes hold

JULY 7, 2020

by Rodger Gwiazdowski, University of Massachusetts Amherst

As thousands of hopeful coronavirus shut-ins look forward to heading to Atlantic beaches for the July 4 holiday, University of Massachusetts Amherst entomologist Rodger Gwiazdowski and colleagues are also heading to the beach—but they'll visit the last quiet natural one protected by the National Park Service at Sandy Hook, New Jersey.

There, Gwiazdowski and a team of biologists will visit part of the Gateway National Recreation Area to survey the beach above the tide line for what they hope is the beginning of a new population of the federally threatened Northeastern Beach Tiger Beetle. In early May they had released almost 200 grub-like larvae at Sandy Hook, which is about 15 miles south of Staten Island with a clear view of Coney Island. On their early July re-visit, the researchers hope to find the larvae emerged as adult beetles.

In collaboration with the U.S. Fish and Wildlife Service and other agencies, Gwiazdowski and colleagues including Joe Elkinton at UMass Amherst plan three years of relocating larvae that are in the last growth stage before they pupate into adults. "We'll do two pre-surveys in early July," Gwiazdowski says. "If we find some, we'll go back later to see if we can determine a peak number."

He points out, "These insects used to be found on seaward beaches all up and down the East coast but their numbers crashed after 1945. In the 1990s, some were left on Martha's Vineyard and, a few of those were moved to nearby Monomoy Island off Cape Cod. "Now, the Monomoy population has exploded and we're seeing what a pre-discovery population looked like before Henry Hudson and other Europeans arrived."

Making a list of all creatures, great and small

JULY 7, 2020

A paper published July 7, 2020 in the open access journal PLOS Biology outlines a roadmap for creating, for the first time, an agreed list of all the world's species, from mammals and birds to plants, fungi and microbes.

"Listing all species may sound routine, but is a difficult and complex task," says Prof. Stephen Garnett of Charles Darwin University, the paper's lead author. "Currently no single, agreed list of species is available." Instead, some iconic groups of organisms such as mammals and birds have several competing lists, while other less well-known groups have none.

This causes problems for organizations and governments that need reliable, agreed, scientifically defensible and accurate lists for the purposes of conservation, international treaties, biosecurity, and regulation of trade in endangered species. The lack of an agreed list of all species also hampers researchers studying Earth's biodiversity.

The new paper outlines a potential solution—a set of ten principles for creating and governing lists of the world's species, and a proposed governance mechanism for ensuring that the lists are well-managed and broadly acceptable.

"Importantly, it clearly defines the roles of taxonomists—the scientists who discover, name and classify species—and stakeholders such as conservationists and government and international agencies," says Dr. Kevin Thiele, Director of Taxonomy Australia and a co-author on the paper. "While taxonomists would have the final say on how to recognize and name species, the process ensures that stakeholders' needs are considered when deciding between differing taxonomic opinions."

Animals who try to sound 'bigger' are good at learning sounds

JULY 7, 2020

Some animals fake their body size by sounding bigger than they actually are. Maxime Garcia from the University of Zurich and Andrea Ravignani from the Max Planck Institute for Psycholinguistics studied 164 different mammals and found that animals that lower their voices to sound bigger are often skilled vocalists. Both strategies—sounding bigger and learning sounds—are likely driven by sexual selection, and may play a role in explaining the origins of human speech evolution.

"If you saw a chihuahua barking as deep as a rottweiler, you would definitely be surprised," says Andrea Ravignani, a researcher at the MPI and the Dutch Sealcentre Pieterburen. Body size influences the frequency of the sounds animals produce, but many animals found ways to sound smaller or bigger than expected.

"Nature is full of animals like squeaky rottweilers and tenor chihuahuas," explains Ravignani. Some animals fake their size by developing larger vocal organs that lower their sound, which makes them sound larger than you would expect. Other animals are good at controlling the sounds they produce. Such strategies (called dishonest signalling by biologists) could be driven by sexual selection, as males with larger body size or superior singing skills (hitting very high or low notes) attract more females (or vice versa).

Garcia and Ravignani wondered whether some animals may have learned to make new sounds as a strategy to attract mates. Few animal species are capable of vocal learning, among them, mammals such as seals, dolphins, bats and elephants. For instance, seals can imitate sounds, and some seals copy call types of successfully breeding individuals. Would animals who often 'fake' their body size also be the ones capable of learning new sounds?

Monday, 6 July 2020

Crunch, crunch: Africa's locust outbreak is far from over

JULY 5, 2020

by Khaled Kazziha and Cara Anna

Locusts swarm on a tree south of Lodwar town in Turkana county, northern Kenya Tuesday, June 23, 2020. The worst outbreak of the voracious insects in Kenya in 70 years is far from over, and their newest generation is now finding its wings for proper flight. (AP Photo/Boris Polo)

The crunch of young locusts comes with nearly every step. The worst outbreak of the voracious insects in Kenya in 70 years is far from over, and their newest generation is now finding its wings for proper flight.

The livelihoods of millions of already vulnerable people in East Africa are at stake, and people like Boris Polo are working to limit the damage. The logistician with a helicopter firm is on contract with the United Nations Food and Agricultural Organization, helping to find and mark locust swarms for the targeted pesticide spraying that has been called the only effective control.

"It sounds grim because there's no way you're gonna kill all of them because the areas are so vast," he told The Associated Press from the field in northwestern Kenya on Thursday. "But the key of the project is to minimize" the damage, and the work is definitely having an effect, he said.

For months, a large part of East Africa has been caught in a cycle with no end in sight as millions of locusts became billions, nibbling away the leaves of both crops and the brush that sustains the livestock so important to many families.

"The risk of significant impact to both crops and rangelands is very high," the regional IGAD Climate Prediction & Applications Center said Wednesday in a statement.

DNA helps conservation of elusive tequila bat

JULY 6, 2020

Scientists studying the near-threatened tequila bat, best known for its vital role in pollinating the Blue Agave plant from which the drink of the same name is made from, have analyzed its DNA to help inform conservationists on managing their populations. The findings are published in Global Ecology and Conservation.
Native to the Americas, the tequila bat (Leptonycteris yerbabuenae) lives in caves in some of the hottest desert areas in Mexico. Given that bats are highly mobile, and that migratory species tend to mix constantly with other bat populations, it is hard for conservationists to know whether they are protecting the best sites for the tequila bats to roost.

While known that some tequila bat populations migrate in Mexico's spring months to the Sonoran Desert to give birth to their pups and pollinate a variety of plants iconic to the region, including the economically important Blue Agave plant. Other tequila bat populations inhabit Southern Mexico year-round, forming large breeding colonies in the winter months.

This study aimed to help better inform conservationists of the species' breeding and migratory patterns by determining whether the bats inhabiting Southern Mexico year-round have a similar ancestral origin to those that migrate to the Sonoran Desert.

Read on

Sunday, 5 July 2020

Good night? Satellite data uncovers dolphins on the move at nighttime

Date: June 2, 2020
Source: Florida Atlantic University
More than 1,000 bottlenose dolphins live in the Indian River Lagoon year-round. This estuarine system along the southeast coast of Florida is a narrow and convoluted ecosystem with interconnected bodies of water, a handful of ocean inlets, and numerous small rivers, creeks and canals that release freshwater into the lagoon. While this population of dolphins in the lagoon has been studied extensively, what they do at nighttime is still a mystery.
Researchers from Florida Atlantic University's Harbor Branch Oceanographic Institute in collaboration with Seven Degrees of Mapping LLC, and Hubbs-SeaWorld Research Institute, are the first to use satellite telemetry on this dolphin population, providing unique insights into their behavioral ecology during the overnight hours. Detailed information about their nocturnal movements and habitat use will give scientists a more complete ecological understanding of this population. These dolphins face many direct and indirect threats including boat strikes, entanglements, and environmental contamination.
Results of the study, published in the journal Animal Biotelemetry, provide the first documentation of Indian River Lagoon dolphins regularly leaving the brackish waters of the estuarine system and, not only traveling into the ocean, but swimming substantial distances -- up to 20 kilometers -- up freshwater rivers, creeks, and canals. These journeys do not appear to be extended stays in freshwater, which can be detrimental to dolphin health, but instead involve many brief trips upriver. Findings reveal that they have a larger range that encompasses more habitats than previously thought.


Alien frog invasion wreaks havoc on natural habitat

Date: June 4, 2020
Source: University of South Australia
Indiscriminate feeding by an alien population of the carnivorous spotted-thighed frog -- could severely affect the native biodiversity of southern Australia according to a new study by the University of South Australia.
The invasive amphibian -- Litoria cyclorhyncha -- which has hitchhiked across the Nullarbor from Western Australia -- has now established a community of 1000-plus in Streaky Bay, South Australia, with sightings also confirmed on the Eyre Peninsula and at the Adelaide airport.
This is the first study of the spotted-thighed frog's diet in its invaded range with the findings providing important biological information about the impact of the alien species on natural ecosystems.
Ecology experts, UniSA's Associate Professor Gunnar Keppel and Christine Taylor, say the potential of the spotted-thighed frog spreading to other parts of Australia is very concerning given its destructive eating patterns.
"This frog is an indiscriminate eating machine that will devour just about anything it can fit into its mouth," Taylor says.
"We're talking about a relatively large, predatory tree frog that, as a species is alien to South Australia, and it could have devastating impact on invaded habitats.
"As it eats away at local species, it's impacting the natural ecosystem, which can displace or destroy local food webs, outcompete native birds, reptiles and mammals for resources, and potentially change natural biodiversity."
Biodiversity is the theme of this year's United Nations World Environment Day.

Read on

Catastrophic disease events in marine mammals mostly caused by viruses

Date: June 18, 2020
Source: Virginia Tech
As the COVID-19 pandemic sweeps across the globe, people are beginning to understand, at a very personal level, the ways in which infectious diseases can devastate life. But disease outbreaks are not confined to just humans or to life on land.
"We are perhaps more alert than ever to the catastrophic impacts of infectious disease in both humans and animals. Our task now is to begin to understand what drives these events, particularly in species like marine mammals, where our knowledge is even more limited," said Claire Sanderson, a research associate in the Department of Fish and Wildlife Conservation within the College of Natural Resources and Environment and the research coordinator of the Center for African Resources: Animals, Communities, and Land Use (CARACAL).
In 2000, over 10,000 endangered Caspian seals died in less than a four-month span. Researchers later discovered that the culprit behind this devastating mass mortality event was canine distemper virus.
Infectious disease-induced mass mortality events are known to afflict a variety of species, including invertebrates, birds, fish, and both land and aquatic mammals. However, these events in aquatic mammals are understudied compared to their land-dwelling counterparts.

Friday, 3 July 2020

Shhhh, the whales are resting

Date: June 16, 2020
Source: Aarhus University
We need new guidelines to shield whales from human-made noise to ensure them some peace and quiet. It is no good keeping whale-watching boats out of whales' sight if the noise from the boats' engines disturb the whales most. And whales can hear the boats' engines from far away, according to a Danish-Australian research team.
Whale-watching has become a multi-billion-dollar business, and companies want to give passengers the best possible experience by positioning their boats close to the whales.
Public authorities around the globe have set restrictions on whale-watching boats in order to protect whales. For example, some countries require boats to keep a distance of at least 100 metres from the whales, or require them to stay behind or next to the whales at slow speed. However, scientific studies have shown that even when boats keep to these restrictions, the whales are still disturbed and change behaviour:
They dive, change course, swim faster, breathe more often, disperse and may make different sounds compared to usual.
Now, a team of researchers from Aarhus University in Denmark believe they have found an explanation: The engines in some of the boats are too loud. And authorities can now place noise emission standards on this noise.

First egg from Antarctica is big and might belong to an extinct sea lizard

Date: June 17, 2020
Source: University of Texas at Austin
In 2011, Chilean scientists discovered a mysterious fossil in Antarctica that looked like a deflated football. For nearly a decade, the specimen sat unlabeled and unstudied in the collections of Chile's National Museum of Natural History, with scientists identifying it only by its sci-fi movie-inspired nickname -- "The Thing."
An analysis led by researchers at The University of Texas at Austin has found that the fossil is a giant, soft-shell egg from about 66 million years ago. Measuring in at more than 11 by 7 inches, the egg is the largest soft-shell egg ever discovered and the second-largest egg of any known animal.
The specimen is the first fossil egg found in Antarctica and pushes the limits of how big scientists thought soft-shell eggs could grow. Aside from its astounding size, the fossil is significant because scientists think it was laid by an extinct, giant marine reptile, such as a mosasaur -- a discovery that challenges the prevailing thought that such creatures did not lay eggs.
"It is from an animal the size of a large dinosaur, but it is completely unlike a dinosaur egg," said lead author Lucas Legendre, a postdoctoral researcher at UT Austin's Jackson School of Geosciences. "It is most similar to the eggs of lizards and snakes, but it is from a truly giant relative of these animals."
A study describing the fossil egg was published in Nature on June 17.
Co-author David Rubilar-Rogers of Chile's National Museum of Natural History was one of the scientists who discovered the fossil in 2011. He showed it to every geologist who came to the museum, hoping somebody had an idea, but he didn't find anyone until Julia Clarke, a professor in the Jackson School's Department of Geological Sciences, visited in 2018.
"I showed it to her and, after a few minutes, Julia told me it could be a deflated egg!" Rubilar-Rogers said.
Using a suite of microscopes to study samples, Legendre found several layers of membrane that confirmed that the fossil was indeed an egg. The structure is very similar to transparent, quick-hatching eggs laid by some snakes and lizards today, he said. However, because the fossil egg is hatched and contains no skeleton, Legendre had to use other means to zero in on the type of reptile that laid it.

Chemistry behind bombardier beetle's extraordinary firepower

Date: June 16, 2020
Source: Stevens Institute of Technology
If you want to see one of the wonders of the natural world, just startle a bombardier beetle. But be careful: when the beetles are scared, they flood an internal chamber with a complex cocktail of aromatic chemicals, triggering a cascade of chemical reactions that detonates the fluid and sends it shooting out of the insect's spray nozzle in a machine-gun-like pulse of toxic, scalding-hot vapor. The explosive, high-pressure burst of noxious chemicals doesn't harm the beetle, but it stains and irritates human skin -- and can kill smaller enemies outright.
The beetle's extraordinary arsenal has been held up by some as a proof of God's existence: how on earth, creationists argue, could such a complex, multistep defense mechanism evolve by chance? Now researchers at Stevens Institute of Technology in Hoboken, N.J. show how the bombardier beetle concocts its deadly explosives and in the process, learn how evolution gave rise to the beetle's remarkable firepower.
"We explain for the first time how these incredible beetles biosynthesize chemicals to create fuel for their explosions," said Athula Attygalle, a research professor of chemistry and lead author of the work, which appears today in the July 2020 issue of the Science of Nature. "It's a fascinating story that nobody has been able to tell before."
To trace the workings of the beetle's internal chemistry set, Attygalle and colleagues at University of California, Berkeley used deuterium, a rare hydrogen isotope, to tag specially synthesized chemical blends. The team led by Kipling Will then either injected the deuterium-labeled chemicals into the beetles' internal fluids, or mixed them with dog food and fed them to the beetles over a period of several days.
Attygalle's team sedated the bugs by popping them in the freezer, then gently tugged at their legs, annoying the sleepy insects until they launched their defensive sprays onto carefully placed filter papers. The team also dissected some beetles, using human hairs to tie closed the tiny ducts linking their chemical reservoirs and reaction chambers, and sampling the raw chemicals used to generate explosions.

Thursday, 2 July 2020

Shining like a diamond: A new species of diamond frog from northern Madagascar

Date: June 16, 2020
Source: Pensoft Publishers
Despite the active ongoing taxonomic progress on Madagascar's frogs, the amphibian inventory of this hyper-diverse island is still very far from being complete. The known diversity of the diamond frog genus Rhombophryne in Madagascar has increased significantly (more than doubled!) over the last 10 years, but still there are several undescribed candidate species awaiting description. New species are constantly being discovered in Madagascar, often even within already well-studied areas. One such place is the Montagne d'Ambre National Park in northern Madagascar.
Montagne d'Ambre National Park is widely known for its endemic flora and fauna, waterfalls and crater lakes, and considered to be a relatively well-studied area. Yet, only two studies have been published so far on the reptiles and amphibians of the Park.
Serving the pursuit of knowledge of the herpetofauna in the region, Germany-based herpetologist Dr. Mark D. Scherz (Bavarian State Collection of Zoology, Technical University of Braunschweig, University of Konstanz) published a description of a new diamond frog species: Rhombophryne ellae, in the open-access journal Zoosystematics and Evolution.
"As soon as I saw this frog, I knew it was a new species," shares Dr. Scherz, "The orange flash-markings on the legs and the large black spots on the hip made it immediately obvious to me. During my Master's and PhD research, I studied this genus and described several species, and there are no described species with such orange legs, and only few species have these black markings on the hip. It's rare that we find a frog and are immediately able to recognise that it is a new species without having to wait for the DNA sequence results to come back, so this was elating."

African lion counts miss the mark, but new method shows promise

Date: June 18, 2020
Source: University of Queensland
The current technique used for counting lion populations for research and conservation efforts doesn't add up, according to a University of Queensland researcher.
But UQ PhD candidate Mr Alexander Braczkowski has been investigating new methods of photographing and reviewing data analytics to count lions.
"African lions receive immense publicity and conservation attention," Mr Braczkowski said.
"Yet their populations are thought to have experienced a 50 per cent decline since 1994 -- coincidentally the same year Disney's The Lion King was released.
"Current calculations suggest that between 20,000 and 30,000 lions remain in the wild -- scattered among 102 populations across approximately 2.5 million square kilometres of Africa.
"Our research shows that the majority of estimates on African lion population and density are based on track counts, audio lure surveys and expert solicitation -- which are simply not reliable enough to understand how lion populations are doing over time."
According to Mr Braczkowski, a recently developed technique has shown promise in better counting big cats and understanding their movements.
"It involves driving extensively and searching actively for lions, and then taking high quality photographs to individually identify them and noting their locations," Mr Braczkowski said.
"We use an analytical method known as Spatially Explicit Capture-Recapture (SECR).
"For African lions, it was first applied in the Maasai Mara by Dr Nicholas Elliot and Dr Arjun Gopalaswamy, and has now been adopted by the Kenya Wildlife Service and others to survey lions and other carnivores across the country."


Sumatran tiger killed in suspected poisoning

JUNE 23, 2020
An official takes a sample from the carcass of a male Sumatran tiger found buried at the Batang Gadis national park
A Sumatran tiger has been found dead in a suspected poisoning, an Indonesian official said Tuesday, a day after alleged poachers were charged with killing another of the critically endangered big cats in a separate case.
The buried carcass of a male tiger was uncovered in North Sumatra's Batang Gadis national park following a tip off, according to park authorities, who said some of the creature's pelt as well as organs were missing.
"Our preliminary conclusion is that the tiger was poisoned," park spokesman Bobby Nopandry told AFP.
Locals, including a village head, said the poisoning was orchestrated by farmers who were angry the tiger had killed their livestock, he added.
Human-animal conflicts are common in the Southeast Asian archipelago—especially in areas where the clearing of rainforest to make way for palm oil plantations is destroying natural habitats.
In the past year Sumatra has seen a spate of fatal tiger attacks on humans.
Indonesia is also battling rampant poaching, which accounts for almost all Sumatran tiger deaths, according to TRAFFIC, a global wildlife trade monitoring network.
On Monday police in Sumatra's Aceh province said they had arrested four suspected traffickers for killing a Sumatran tiger and attempting to sell its body parts.
Sumatran tigers are considered critically endangered by the International Union for Conservation of Nature, with fewer than 400 believed to remain in the wild.
Tiger parts are widely used in traditional medicine—particularly in China—despite overwhelming scientific evidence they have no beneficial value.

Wednesday, 1 July 2020

A new social role for echolocation in bats that hunt together

Date: June 19, 2020
Source: Smithsonian Tropical Research Institute
Searching for food at night can be tricky. To find prey in the dark, bats use echolocation, their "sixth sense." But to find food faster, some species, like Molossus molossus, may search within hearing distance of their echolocating group members, sharing information about where food patches are located. Social information encoded in their echolocation calls may facilitate this foraging strategy, according to a recent study by Smithsonian Tropical Research Institute (STRI) scientists and collaborating institutions published online in Behavioral Ecology.
Previous research has identified several ways in which echolocation can transfer social information in bats. For example, "feeding buzzes," the echolocation calls bats produce to home in on prey they've spotted, can serve as cues of prey presence to nearby eavesdropping bats. On the other hand, echolocation calls that bats produce while looking for food, called "search-phase" calls, were not known to transfer social information.

World’s top tapir expert prepares for unprecedented Amazon mission

by Naira Hofmeister on 24 June 2020 | Translated by Roberto Cataldo
Brazilian conservation biologist PatrĂ­cia Medici first won a Whitley Award, the “Green Oscars” for conservation science, in 2008; this year, she’s the recipient of the top tier of the prize, the Whitley Gold Award.
She will use the $75,000 prize to fund the new stage of her studies, in which she plans for the first time to study the lowland tapir in the Amazon.
Medici has already spent two decades studying the species, South America’s largest land mammal, in the Atlantic Forest, the Pantanal wetlands, and the Cerrado grassland.
She hopes to use the next stage of the study, in the Amazon, to expand understanding of the species by seeing how it reacts to deforestation driven by mining, large-scale agriculture, and logging.
Social and travel restrictions imposed in response to the COVID-19 pandemic prevented Brazilian conservationist PatrĂ­cia Medici from going to London last month to receive one of the most prestigious awards in the world of conservation science.
The Whitley Gold Award — the top prize given out every year by the Whitley Fund for Nature — is considered such a major honor that it is known as the “Green Oscars” and is handed out by Princess Anne of England, the fund’s patron. Medici, who received her first Whitley Award in 2008, was named the recipient this year for her work to conserved Brazil’s threatened wildlife in general and the lowland tapir (Tapirus terrestris) in particular. The awards ceremony at the Royal Geographical Society has now been rescheduled to December, if things are normal by then.
Until then, however, Medici says she hopes the health crisis doesn’t prevent her from resuming her expeditions with the Lowland Tapir Conservation Initiative (Incab) in the second half of 2020.


‘It’s a success’: Pangolins return to a region where they were once extinct

by Elizabeth Claire Alberts on 23 June 2020
Temminck’s pangolins have been “ecologically extinct” in South Africa’s KwaZulu-Natal province Africa for the past 30 or 40 years, but a new program managed by the African Pangolin Working Group is reintroducing the scaly anteaters back into this region.
Pangolins rescued from the illegal wildlife trade tend to be physically ill and mentally stressed, and need to go through a lengthy rehabilitation process before they can be released.
Instead of simply releasing pangolins back into the wild, the African Pangolin Working Group puts the animals through a “soft release” program, and continues to closely monitor them through GPS satellite and VHF radio tracking tags.
In 2019, seven pangolins were released at Phinda Private Game Reserve in KwaZulu-Natal; two died of natural causes, but the remaining five are doing well.
Pangolins have been locally extinct in South Africa’s KwaZulu-Natal province for the last 30 or 40 years, experts say. But now, local conservationists are working to slowly reintroduce these shy, sensitive animals in a world-first effort to reinstate wild populations.

Read on

Monday, 29 June 2020

Illusionist Frog Attracts Mates Without Unwanted Attention From Predators - The simultaneous mating calls of the male pug-nosed tree frog confuses bats but not female frogs – via Herp Digest

By Alex Fox 
MAY 7, 2020
Male tungara frogs of Central and South America call out to potential mates with reckless abandon. During the rainy season, they wait for pockets of relative silence amid the cacophony of the rainforest and belt out a song that could attract females’ attention or get them eaten by an eavesdropping bat. Even worse, their most seductive calls are also more likely to turn them into someone’s dinner.
It might seem like a rough trade off, but trying to stand out from the acoustic lineup is typical among frogs, explains Ximena Bernal, an ecologist at Purdue University and researcher at the Smithsonian Tropical Research Institute in Panama.
In the rainforest’s dry season, another frog species has a more confusing way of flirting. When it’s time for male pug-nosed tree frogs to turn on the charm, they all call out at the same time.
“Synchronizing calls is like talking over other people which, as we all know, reduces our ability to understand what the person is saying,” says Bernal via email. Calling out at the same time seemed like a confusing strategy for pug-nosed frogs to get dates, but the tungara’s sometimes fatal bids for attention gave Bernal and her colleagues a clue.
After studying the pug-nosed frogs in the rainforests of Panama and in the lab, the researchers have found that the near-perfect synchrony of the frogs’ mating calls confuses their would-be predators—all while remaining plenty alluring to females, reports Pratik Pawa for Science News.
When one pug-nosed tree frog (Smilisca sila) trumpets his love song, other nearby males start their calls almost instantly. With all the frogs calling out at once, bats and most other vertebrates think the sound is all coming from the frog that started the chorus.
“Humans experience this illusion too, it’s called the ‘Precedence Effect’. When we hear two short sounds in quick succession, we think the sound is only coming from the location of the first sound,” says Bernal, who is also affiliated with Purdue University in Indiana, in a statement.
This auditory illusion obscures the locations of all the frogs who joined in late and protects them from predators, the researchers report in the journal American Naturalist.
This places the poor saps leading the call at a big disadvantage, which drives each frog to hold its note as long as possible—resulting in gulfs of silence between the bouts of song, Bernal tells Science News.
But what do the female frogs think? Surprisingly, the team’s experiments suggest females don’t show any preference for the bold males who initiated the calls. What remains a mystery is how the females avoid falling prey to their species’ own illusory tactics and remain capable of choosing their mate. 
This phenomenon is something Bernal hopes to explore in future research. “Is there something specific about their hearing mechanisms that allows them to detect and accurately locate two signals even though they are produced milliseconds apart?” she wonders.Synchronous calls aren’t this illusionist amphibian’s only tactics for evading predators. Males are known to prefer to sing near waterfalls. This placement isn’t just for ambiance; the sound of the rushing water overlaps with the frequency of the males’ calls and helps obscure them to hungry bats.
Prior research has also shown they vary their calls in accordance with the moon. Males are more vocal on nights when moonlight is brighter and they can more easily spot marauding bats, and quieter when it’s darker.
Bernal speculates that the pug-nosed frog’s choice of mating season may account for its multiple strategies for avoiding predators: “This is the main species calling in the dry season so it may be that it is under strong selection from many frog-eating beasts.”

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