Bat faeces and biodiversity in Indonesia


This 2015 video says about itself:

Bat Man of Borneo | Expedition Raw

Braving guano, urine, and infectious diseases is all in a day’s work for bat ecologist Donald McFarlane, who descends into the depths of Borneo’s Gomantong Caves [in Malaysia] to study the bats that live there.

From James Cook University in Australia:

Holy Pleistocene Batman, the answer’s in the cave

Let’s say you wanted to solve a 20,000-year-old mystery, where would you start?

April 25, 2019

Summary: Examining a 3-meter stack of bat feces has shed light on the landscape of the ancient continent of Sundaland. The research could help explain the biodiversity of present-day Borneo, Sumatra, and Java. It could also add to our understanding of how people moved through the region.

Let’s say you wanted to solve a 20,000-year-old mystery, where would you start? Perhaps archaeology and geology come to mind. Or, you could sift through a 3-metre pile of bat faeces.

Researchers from James Cook University in Cairns, Australia, chose the bat poo in their quest to answer to a long-standing question: why is there some much biodiversity on the islands of Sumatra, Borneo and Java, when not so long ago (geologically speaking) they were all part of one vast continent?

One theory has been that the former continent (Sundaland) was dissected by a savanna corridor. “That might explain why Sumatra and Borneo each have their own species of orang-utan, even though they were linked by land for millions of years,” Dr Chris Wurster said. “The corridor would have divided the two separate rainforest refuges, as the sea does now.”

The corridor theory has been boosted by millions of insect-eating bats, which have gathered evidence about the landscape over millennia and deposited it in layers in their caves.

“Bat poo is highly informative, and especially so in the tropics, where the climate can make some of the more traditional modes of investigation less available,” Dr Wurster said.

A three-metre pile of bat faeces at Salah Cave in Borneo gave the researchers a 40,000-year-old record composed of insect skeletons.

“We can’t tell what insects the bats were eating throughout that time, because they’re in tiny fragments, but we can read the chemistry,” Dr Wurster said.

“Eating insects that have been feeding on tropical grasses results in faeces with a characteristic chemical imprint. It’s quite different from the result you’d get from eating insects that fed on tropical trees.”

According to the bat record the landscape around Saleh Cave (now featuring lush rainforest) was once dominated by tropical grasses.

“Combined with other cave studies in the region, this leads us to support the corridor theory, and also gives us some confidence as to the extent of the corridor,” Dr Wurster said.

The corridor could also shed light on human pre-history.

“A savanna corridor, which would be much more easily traversed than rainforest, might help to explain how people moved relatively quickly through this region and on to Australia and New Guinea.”

‘Savanna in equatorial Borneo during the late Pleistocene’ is published in the latest edition of Scientific Reports.

Dr Chris Wurster is a Senior Research Associate at James Cook University, specialising in stable isotope geochemistry.

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Flower preferences of male, female bees


This 2015 video says about itself:

Carpenter bees (the genus Xylocopa in the subfamily Xylocopinae) are large bees distributed worldwide. Some 500 species of carpenter bees are in the 31 subgenera.

Their common name is because nearly all species build their nests in burrows in dead wood, bamboo, or structural timbers (except those in the subgenus Proxylocopa, which nest in the ground).

Carpenter bees are traditionally considered solitary bees, though some species have simple social nests in which mothers and daughters may cohabit. However, even solitary species tend to be gregarious, and often several nest near each other. When females cohabit, a division of labor between them occurs sometimes, where one female may spend most of her time as a guard within the nest, motionless and near the entrance, while another female spends most of her time foraging for provisions.

From Rutgers University in the USA:

With flower preferences, bees have a big gap between the sexes

Female and male bees of the same species frequent different flowers, study finds

April 24, 2019

For scores of wild bee species, females and males visit very different flowers for food — a discovery that could be important for conservation efforts, according to Rutgers-led research.

Indeed, the diets of female and male bees of the same species could be as different as the diets of different bee species, according to a study in the journal PLOS ONE.

“As we get a better sense of what makes flowers attractive to different kinds of bees, maybe we can get smarter about bee conservation,” said lead author Michael Roswell, a doctoral student in the lab of senior author Rachael Winfree, a professor in the Department of Ecology, Evolution, and Natural Resources at Rutgers University-New Brunswick.

Five years ago, when Winfree Lab members were evaluating federally funded programs to create habitat for pollinators, Roswell noticed that some flowers were very popular with male bees and others with females. That spurred a study to test, for as many wild bee species as possible, whether males and females visit different kinds of flowers.

New Jersey is home to about 400 species of wild bees — not including Apis mellifera Linnaeus, the domesticated western honeybee whose males do not forage for food, Roswell noted.

The scientists collected 18,698 bees from 152 species in New Jersey. The bees visited 109 flower species in six semi-natural meadows with highly abundant and diverse flowers. The meadows were managed to promote mostly native flowers that attract pollinators.

Female bees build, maintain, collect food for and defend nests, while male bees primarily seek mates. Both sexes drink floral nectar for food, but only females collect pollen that serves as food for young bees, so they forage at greater rates than males.

From the flowers’ standpoint, both female and male bees are important pollinators — though female bees are more prolific because they spend more time foraging at flowers.

Before mating, the males of some species travel from the area where they were born. Targeting their preferences for flowers may help maintain genetically diverse bee populations, Roswell speculated.

“We see some intriguing patterns, where certain plant families seem relatively preferred or avoided by male bees, or where males have relatively less appetite for visiting flowers that only produce pollen and not nectar,” he said. “That could help pinpoint the right mix of flowers to improve bee conservation down the road.”

Good Pacific green turtle news


This 30 December 2018 video from Australia says about itself:

Tracking Green Turtles in the Great Barrier Reef | Fearless Adventures with Jack Randall

Jack dives into the Great Barrier Reef to wrangle Green Sea Turtles for wildlife conservation and study.

From PLOS:

Immense Pacific coral reef survey shows green sea turtle populations increasing

First comprehensive in-water survey shows key role of ocean temperature and human protection

April 24, 2019

Densities of endangered green turtles are increasing in Pacific coral reefs, according to the first comprehensive in-water survey of turtle populations in the Pacific. The study, by Sarah Becker of the Monterey Bay Aquarium in California and colleagues, publishes April 24 in the open-access journal PLOS ONE.

Coral-dwelling sea turtles have long been endangered due largely to human exploitation — hawksbills for tortoiseshell and green turtles for food — and destruction of coral reef habitat, but the institution of global protection efforts beginning in the 1970s aimed to reverse this decline. Land-based surveys of breeding and nesting sites have provided important evidence of population sizes, but are limited in scope and without confirmation from the ocean where the turtles spend the vast majority of their time.

To more fully understand the density of the populations of these two turtle species, as well as the environmental and anthropogenic factors that have driven them, the authors combined data from 13 years of in-water visual surveys of turtle abundance near 53 islands, atolls, and reefs throughout the U.S. Pacific. During a survey, a slow-moving boat tows a pair of divers at about 15 meters below the surface, where they record details of habitat and sea life as it comes into view. In all, the surveys covered more than 7,300 linear kilometers and observed more than 3,400 turtles of the two species.

Survey data showed that American Samoa had the highest density of hawksbills, while the Pacific Remote Islands Area, a mostly uninhabited region about a thousand miles southwest of Hawaii, had the most green turtles. Hawksbill numbers were far lower (< 10%) than green turtle counts, indicating that many conservation threats still exist for this species. Density of green turtles were driven primarily by ocean temperatures and productivity, but suggested effects from historical and present-day human impacts. Over the survey period, green turtle populations were either stable or increased. The lowest density but the highest annual population growth was found in the Hawaiian Islands, suggesting that protective regulations may be paying off in allowing green turtle populations to rebound.

Becker adds: “This study represents one of the largest sea turtle population surveys ever conducted, filling critical gaps on in-water abundance and drivers of population density. Across the tropical Pacific several locations held impressive densities of sea turtles, and in all regions densities were driven by bottom-up forces like ocean temperatures and productivity and top-down forces such as human impacts.”

Gouldian finches, why so colourful?


This 2017 video from Australia is called Gouldian Finch Conservation – ABC News.

From Cornell University in the USA:

Why unique finches keep their heads of many colors

An underlying selection mechanism prevents one color from dominating

April 23, 2019

There appears to be an underlying selection mechanism at work among Gouldian Finches — a mechanism that allows this species to produce and maintain individuals with red heads, black heads, and yellow heads. Research by scientists from the the University of Sheffield in the United Kingdom, the Cornell Lab of Ornithology, and other institutions, reveals what this additional evolutionary process might be. Findings were published today in the journal Nature Communications.

“Most people have heard of natural selection,” says lead author Kang-Wook Kim at the University of Sheffield. “But ‘survival of the fittest’ cannot explain the color diversity we see in the Gouldian Finch. We demonstrate that there is another evolutionary process — balancing selection — that has maintained the black or red head color over thousands of generations.”

The yellow-headed type (actually more orange) is produced by a completely different mechanism that is not yet understood. Yellow-headed Gouldian Finches make up less than one percent of the wild population.

“Having distinct multiple color types — a polymorphism — maintained within a species for a long time is extremely rare,” explains co-author David Toews, who did this work as a postdoctoral researcher at the Cornell Lab and who is now at Pennsylvania State University. “Natural selection is typically thought of in a linear fashion — a mutation changes a trait which then confers some reproductive or survival advantage, which results in more offspring, and the trait eventually becomes the sole type in the population.”

Studies from Macquarie University in Australia have shown the red-headed finches have the apparent advantage. Female Gouldian Finches of all colors prefer the red-headed males, who also happen to be more dominant in the social hierarchy. So why hasn’t the black-headed type disappeared? It turns out there are disadvantages to having a red head, too, such as higher levels of stress hormones in competitive situations.

“If advantages are cancelled out by concurrent disadvantages, these two color types can be maintained — that’s balancing selection,” Toews says. “Red forms are not as common in the wild, so the counterbalancing pressure reduces the advantage of being red. That’s super cool!”

Teams from the University of Sheffield and the Cornell Lab independently zeroed in on a particular gene called follistatin which is found on the Gouldian Finch sex chromosome and regulates melanin to produce either red- or black-headed finches. Rather than competing, the two teams decided to join forces and share their data. For the yellow morph, a different gene, not located on the sex chromosome, is controlling the head pigmentation, but it hasn’t yet been found and it’s not clear what forces are allowing the yellow morph to persist in the wild.

In another twist, Toews and co-author Scott Taylor, at the University of Colorado-Boulder, have done previous research that revealed the genes likely governing the plumage differences between North American Blue-winged and Golden-winged Warblers — and one of those regions is in the same spot on the sex chromosome that differs among Gouldian Finches with different head colors.

“We didn’t expect we’d locate the exact genomic region that governs plumage differences in both the Gouldian Finch and the two warblers,” says Toews. “But now that we’ve done it, it opens up the possibility that the same region in other species may also be controlling plumage color.”

Aquatic ankylosaur dinosaur discovery?


This 21 April 2019 video says about itself:

An Aquatic Ankylosaur?

There were once some very strange dinosaurs, but one of the strangest may have been a species of small, possibly fish-eating aquatic ankylosaurLiaoningosaurus paradoxus.

Brazilian river dolphins communication, new study


This 2014 video says about itself:

A new species of river dolphin has been discovered by scientists working in Brazil. This is the fifth known species of its kind, and there are an estimated one thousand of the dolphins living in the Araguaia river basin.

Researchers from the Federal University of Amazonas ran genetic testing on some of the dolphins to be certain that a new species had been found. The last time a new species of river dolphin was discovered was back in 1918.

Doctor Tomas Hrbek, lead author of the study, is quoted as saying: “It is very similar to the other ones. It was something that was very unexpected, it is an area where people see them all the time, they are a large mammal, the thing is nobody really looked.” The Araguaia dolphins are smaller and reportedly have fewer teeth than the Amazon river dolphins, also called boto or pink dolphins, which are believed to be the most intelligent of the river dolphins.

From the University of Vermont in the USA:

Mysterious river dolphin helps crack the code of marine mammal communication

April 19, 2019

The Araguaian river dolphin of Brazil is something of a mystery. It was thought to be quite solitary, with little social structure that would require communication. But Laura May Collado, a biologist at the University of Vermont, and her colleagues have discovered that the dolphins can actually make hundreds of different sounds to communicate, a finding that could help uncover how communication evolved in marine mammals.

“We found that they do interact socially and are making more sounds than previously thought,” she says. “Their vocal repertoire is very diverse.”

The findings of May Collado are her colleagues were published in the journal PeerJ on April 18.

The Araguaian dolphins, also called botos, are a difficult animal to study. They are hard to find in the first place, and while the waters of the Araguaia and Tocatins rivers are clear, it is challenging to identify individuals because the dolphins are skittish and hard to approach.

Luckily, Gabriel Melo-Santos, a biologist from the University of St Andrews in Scotland and leader of the project, found a fish market in the Brazilian town of Mocajuba where the botos regularly visit to be fed by people shopping there. The clear water and regular dolphin visits provided a unique opportunity to get a close look at how the animals behave and interact, and to identify and keep track of various individuals.

The team used underwater cameras and microphones to record sounds and interactions between the dolphins at the market, and took some genetic samples. They identified 237 different types of sounds the dolphins make, but even with 20 hours of recordings the researchers don’t believe they captured the animals’ entire acoustic repertoire. The most common sounds were short, two-part calls that baby dolphins made when they were approaching their mothers.

“It’s exciting; marine dolphins like the bottlenose use signature whistles for contact, and here we have a different sound used by river dolphins for the same purpose,” says May Collado. The river dolphins also made longer calls and whistles, but these were much rarer, and the reasons for them are not yet clear. But there is some indication that whistles serve the opposite purpose than in bottlenose dolphins, with the botos using them to maintain distance rather than for group cohesion.

The acoustic characteristics of the calls are also interesting; they fall somewhere between the low-frequency calls used by baleen whales to communicate over long distances, and the high-frequency ones used by marine dolphins for short distances. May Collado speculates that the river environment may have shaped those characteristics.

“There are a lot of obstacles like flooded forests and vegetation in their habitat, so this signal could have evolved to avoid echoes from vegetation and improve the communication range of mothers and their calves,” she says.

May Collado and her colleagues next want to study whether the same diversity of communication is seen in other populations of Araguaian river dolphins that are less accustomed to humans, and compare them to their relatives elsewhere in South America. The Araguaian dolphins are closely related to two other species, the Bolivian river dolphin and Amazon river dolphin; the Araguaian dolphins were only described as a separate species in 2014, and that classification is still under debate. But there seems to be a large amount of variation in the repertoire of sounds each species makes.

The Amazon dolphins in Ecuador, studied by May Collado in 2005, are generally very quiet. “We need more information on these other species and more populations,” she says. “Why is one population chattier than others and how do these differences shape their social structure?”

May Collado says the work could help researchers gain clearer understanding of how communication evolved in marine mammals. Similar calls have been reported in pilot whales and killer whales, for example, and the similarities and differences between different species could help tease out which signals evolved first, and why.

The river dolphins are evolutionary relics, represented by just a few species around the world, and they diverged from other cetaceans much earlier than other dolphins. So these calls may have arisen first in river dolphins, then later evolved in marine dolphins into whistles and calls but in a different social context. Or was there a change in the function of the calls, with this kind of sound being used for group identity in killer whales, and individual identity in river dolphins? The calls may also have other functions in addition to identity, perhaps indicating group identity, or providing information on emotional state.

“We can’t say what the evolutionary story is yet until we get to know what sounds are produced by other river dolphins in the Amazon area, and how that relates to what we found,” she says. “We now have all these new questions to explore.”

Fish warn others chemically about dangers


This june 2013 video is called Fathead minnows in my pond.

From the University of Saskatchewan in Canada:

Fish under threat release chemicals to warn others of danger

April 18, 2019

Fish warn each other about danger by releasing chemicals into the water as a signal, research by the University of Saskatchewan (USask) has found.

The USask researchers discovered that wild fish release chemicals called ‘disturbance cues’ to signal to other fish about nearby dangers, such as predators.

The findings may have implications for fish conservation efforts across the globe.

“Disturbance cues may help to explain why some fish populations crash after they decline past a certain point,” said Kevin Bairos-Novak, a graduate student member of the research team.

While researchers have been aware that fish release chemicals into the water for 30 years, this is the first time their use has been studied.

The findings, involving researchers from the USask biology department and the Western College of Veterinary Medicine, are published in the Journal of Animal Ecology.

Fish signaled most when in the presence of familiar fish, but signaled far less or not at all when in the presence of strangers, or when on their own.

The signals provoked a ‘fright response’ in fish they knew, including freezing, dashing about and then shoaling tightly together. Fish use this behavior to defend themselves against predators.

“When minnows

The research is about fathead minnows. They live in North America.

were present alongside familiar minnows, they were much more likely to produce signals that initiated close grouping of nearby fish, a strategy used to avoid being eaten by predators,” said Bairos-Novak, who is now at James Cook University, Australia.

Disturbance cues are voluntarily released by prey after being chased, startled or stressed by predators.

One of the main constituents of the signal is urea, found in fish urine.

Fathead minnows, caught at a lake, were placed in groups with familiar fish, unfamiliar fish or as isolated individuals. The research team then simulated a predator chase. The fish responded by shoaling, freezing and dashing when they received a signal from a group they knew. But they did not take significant defensive action when receiving cues from unfamiliar fish or isolated minnows.

Disturbance cues are voluntarily released by prey after being chased, startled or stressed by predators.

“It is exciting to discover a new signaling pathway in animals,” said Maud Ferrari, Bairos-Novak’s supervisor and a behavioural ecologist in the veterinary college’s Department of Veterinary Biomedical Sciences. “We found that fish are able to manipulate the behaviour of other individuals nearby by issuing a signal.”

The research was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC).