Back Beach

dooagh-beachA beach that was swept away more than 30 years ago from a remote island off the west coast of Ireland has reappeared after thousands of tonnes of sand were deposited on top of the rocky coastline.
The 300-metre beach near the tiny village of Dooagh on Achill Island vanished in 1984 when storms stripped it of its sand, leaving nothing more than a series of rock pools.
But after high spring tides last month, locals found that the Atlantic Ocean had returned the sand.
“It’s enormously significant,” Sean Molloy of Achill’s tourism office told the Irish Times newspaper, recalling how the popular beach once sustained four hotels and a number of guesthouses on the west coast of the island of 2,600 people.
“Achill already has five blue-flag beaches, so we are hoping that in time it will be awarded a sixth.”
The island, the largest off the coast of Ireland, forms part of the Wild Atlantic Way, a tourist trail stretching from the south of the country to the north-west that has benefited from a tourist boom in the European Union’s fastest-growing economy.

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Aussie Bites

An Australian-first national analysis of 13 years’ data on bites and stings from venomous creatures reveals Australia’s towns and cities are a hot-spot for encounters.

The stereotype-busting research also shows that of all Australia’s venomous creatures, it is bees and other insects, not snakes, spiders, or jellyfish, that pose the biggest public health threat.

Including fatalities, venomous stings and bites resulted in almost 42,000 hospitalisations over the study period. Bees and wasps were responsible for just over one-third (33%) of hospital admissions, followed by spider bites (30%) and snake bites (15%).

Overall, 64 people were killed by a venomous sting or bite, with more than half of these deaths (34) due to an allergic reaction to an insect bite that caused anaphylactic shock.

Snake bites caused 27 deaths. Importantly, snake bite envenoming caused nearly twice as many deaths per hospital admission than other venomous creatures, making snake bite one of the most important venomous injuries to address.

Bees and wasps killed 27 people. Only one case of a beekeeper and one case of a snake catcher was recorded. Tick bites caused three deaths and ant bites another two. And box jellyfish killed three people. There were two unknown insects. No spider bite fatalities were registered.

Public health expert at the Australian Venom Unit at the University of Melbourne, Dr Ronelle Welton, led the study, published in the Internal Medicine Journal. She says she was surprised to find so many deaths and hospitalisations up and down the populated coastal areas of Australia.

“More than half of deaths happened at home, and almost two-thirds (64%) occurred, not in the isolated areas we might expect, but rather in major cities and inner-regional areas where healthcare is readily accessible,” she said.

Researchers believe one of the reasons that anaphylaxis from insect bites and stings has proven deadly may be because people are complacent in seeking medical attention and anaphylaxis can kill quickly.

While three-quarters of snakebite fatalities at least made it to hospital, only 44 per cent of people who died from an allergic reaction to an insect sting got to hospital.

“Perhaps it’s because bees are so innocuous that most people don’t really fear them in the same way they fear snakes,” Dr Welton says. “Without having a previous history of allergy, you might get bitten and although nothing happens the first time, you’ve still developed an allergic sensitivity.”

Western Australia and South Australia were hot spots for stings and bites, and there were no deaths recorded in Tasmania over the decade. Bites and stings were much more likely to occur between April to October.

Dr Welton believes the current national guidelines for prevention and treatment of envenoming is inadequate because we actually know very little about the health burden of venomous creatures.

“From a public health perspective, we can’t make informed decisions until we have a much clearer picture about what’s going on,” she says.

“For example, in South Australia, there are a lot more stings and anaphylaxis from bees. In Queensland there are more snake bites. In Tasmania, their biggest issue is jumper ant anaphylaxis. So the clinical management needs to vary for each state and territory.”

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Feral Cats

Feral cats cover over 99.8% of Australia’s land area, including almost 80% of the area of its islands.

These are just some of the findings of new research which looks at the number of feral cats in Australia.

The research was undertaken by over 40 of Australia’s top environmental scientists and brings together evidence from nearly 100 separate studies across the country.

“Australia’s total feral cat population fluctuates between 2.1 million when times are lean, up to 6.3 million when widespread rain results in plenty of available prey,” said Dr Sarah Legge from The University of Queensland.

The study also looked at what causes variation in cat densities. Cat densities are higher on islands, especially smaller islands.

Inland areas with low rainfall and more open vegetation had higher cat densities than most coastal, wetter areas, but only after extensive rain.

In a worrying finding for conservation managers, cat densities were found to be the same both inside and outside conservation reserves, such as National Parks, showing that declaring protected areas alone is not enough to safeguard the native wildlife.

“Our study highlights the scale and impacts of feral cats and the urgent need to develop effective control methods, and to target our efforts in areas where that control will produce the biggest gains” says Dr Legge.

“At the moment feral cats are undermining the efforts of conservation managers and threatened species recovery teams across Australia.

“It is this difficulty which is pushing conservation managers into expensive, last resort conservation options like creating predator free fenced areas and establishing populations on predator-free islands.

“These projects are essential for preventing extinctions, but they are not enough, they protect only a tiny fraction of Australia’s land area, leaving feral cats to wreak havoc over the remaining 99.8% of the country.”

The research has been funded by the Australian Government’s National Environmental Science Programme and will be important to developing effective strategies for controlling cats and their impacts.

“This new science shows that the density of feral cats in Australia is lower than it is in North America and Europe, and yet feral cats have been devastating for our wildlife,” said Mr Gregory Andrews, Australia’s Threatened Species Commissioner.

“Australia is the only continent on Earth other than Antarctica where the animals evolved without cats, which is a reason our wildlife is so vulnerable to them. This reinforces the need to cull feral cats humanely and effectively.

“With feral cats having already driven at least 20 Australian mammals to extinction, I’m so glad the Threatened Species Strategy is investing in science like this.

“This science reaffirms the importance of the ambitious targets to cull feral cats that I am implementing with the support of Minister Frydenberg under the Threatened Species Strategy,” said Mr Andrews.

According to Dr Legge, “As well as strategically targeting areas for cat control in bushland to maximise the conservation outcomes, we also need to address the issue of feral cats living in heavily urbanised areas, where their densities can be 30 times greater than in natural environments.

“As well as preying on the threatened species that occur in and near urban areas, these urban feral cats may provide a source of feral cats to bushland areas.”

The research was funded by the Threatened Species Recovery Hub of the Australian Government’s National Environmental Science Programme.

It has been published in the research journal Biological Conservation.

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Trapdoor Spider Decline

Recent surveys by Australian scientists have identified an apparent significant decline in the numbers of trapdoor spiders across southern Australia.

Famous for their carefully camouflaged burrows, some with lids or ‘trapdoors’ from which they launch themselves to catch their prey, trapdoor spiders are remarkable animals. The females of some species are known to live in the same burrow for more than 25 years.

Led by the University of Adelaide, in collaboration with the Western Australian Museum, the Queensland Museum, the Department of Parks and Wildlife (WA) and The University of Western Australia, the scientists have compared numbers of trapdoors at various locations across Australia’s southern agricultural and arid zones with survey data from the 1950s to the present. The findings have been published in the journal Austral Entomology.

“We have good historical records of trapdoor spiders going back 60 years which showed population numbers were reasonably good, but recent surveys of the same areas show numbers are extremely low, and in some cases spiders are completely absent,” says project leader Professor Andrew Austin, from the University of Adelaide’s Australian Centre for Evolution Biology and Biodiversity.

Trapdoor spiders are sometimes encountered in domestic gardens in towns and cities around Australia when they emerge from their burrows to feed or look for a mate.

However, these represent just a few common species, when in fact there are several hundred species found in particular habitats, most of which haven’t even received a formal scientific name.

Now there is concern that this major and unique component of Australia’s fauna may be threatened.

“The problem in some areas looks to be that the few spiders surviving are old females, and an absence of males means there is no capacity to reproduce, and they eventually die and the population disappears,” says team member Dr Mark Harvey, a national expert on spiders based at the Western Australian Museum.

“The reasons for this decline are probably complex but are undoubtedly linked to a century of intensive land clearing and the fact that trapdoor spiders are susceptible to soil disturbance around their burrows.”

Lead author Dr Mike Rix, who did his research at the University of Adelaide and is now at the Queensland Museum, says the results of this research are concerning on their own, but may also be representative of a decline in populations of other invertebrate animals.

“To get a better handle on the extent of the problem, there is a real need for more detailed follow up surveys, including to assess where remnant populations still exist,” he says.


 

How The Bees Do It

A honeybee can carry up to 30 percent of its body weight in pollen because of the strategic spacing of its nearly three million hairs. The hairs cover the insect’s eyes and entire body in various densities that allow efficient cleaning and transport.

The research found that the gap between each eye hair is approximately the same size as a grain of dandelion pollen, which is typically collected by bees. This keeps the pollen suspended above the eye and allows the forelegs to comb through and collect the particles. The legs are much hairier and the hair is very densely packed — five times denser than the hair on the eyes. This helps the legs collect as much pollen as possible with each swipe. Once the forelegs are sufficiently scrubbed and cleaned by the other legs and the mouth, they return to the eyes and continue the process until the eyes are free of pollen.

The Georgia Tech team tethered bees and used high speed cameras to create the first quantified study of the honeybee cleaning process. They watched as the insects were able to remove up to 15,000 particles from their bodies in three minutes.

“Without these hairs and their specialised spacing, it would be almost impossible for a honeybee to stay clean,” said Guillermo Amador, who led the study while pursuing his doctoral degree at Georgia Tech in mechanical engineering.

This was evident when Amador and the team created a robotic honeybee leg to swipe pollen-covered eyes. When they covered the leg with wax, the smooth, hairless leg gathered four times less pollen.

The high-speed videos also revealed something else.

“Bees have a preprogrammed cleaning routine that doesn’t vary,” said Marguerite Matherne, a Ph.D. student in the George W. Woodruff School of Mechanical Engineering. “Even if they’re not very dirty in the first place, bees always swipe their eyes a dozen times, six times per leg. The first swipe is the most efficient, and they never have to brush the same area of the eye twice.”

The research also found that pollenkitt, the sticky, viscous fluid found on the surface of pollen grains, is essential. When the fluid was removed from pollen during experiments, bees accumulated half as much.

“If we can start learning from natural pollinators, maybe we can create artificial pollinators to take stress off of bees,” said David Hu, a professor in the Woodruff School of Mechanical Engineering and School of Biological Sciences. “Our findings may also be used to create mechanical designs that help keep micro and nanostructured surfaces clean.”

The study, “Honeybee hairs and pollenkitt are essential for pollen capture and removal,” is published in the journal Bioinspiration and Biomimetics.


 

Bee Curious

Though declines in bee populations have heightened awareness of the importance of pollinating insects to the world’s food supply, numerous bee species remain undescribed or poorly understood.

Utah State University entomologist Zach Portman studies a diverse group of solitary, desert bees that aren’t major pollinators of agricultural crops, but fill an important role in natural ecosystems of the American Southwest, including the sizzling sand dunes of California’s Death Valley.

With Terry Griswold of the USDA-ARS Pollinating Insects Research Unit at Utah State and John Neff of the Central Texas Melittological Institute in Austin, Portman reports nine, newly identified species of the genus Perdita in the December 23, 2016, issue of Zootaxa. His research was supported by a National Science Foundation Graduate Research Fellowship awarded in 2011 and a Desert Legacy Grant from the Community Foundation.

Unexpected finds include the curious ant-like males of two of the species, which are completely different in appearance from their mates.

“It’s unclear why these males have this unique form, but it could indicate they spend a lot of time in the nest,” Portman says. “We may find more information as we learn more about their nesting biology.”

Some of these bees, found exclusively in North America, sport scientific names inspired by Shakespearean characters, such as Perdita titania, named for the fairy queen from A Midsummer Night’s Dream. Elusive and tiny, Portman tracks the bees by watching for their buzzing shadows in the blinding, midday sunlight the diminutive insects tend to favour.

“Their activity during the hottest part of the day may be a way of avoiding predators,” says the doctoral candidate in USU’s Department of Biology and the USU Ecology Center. “They appear to be important pollinators of desert plants commonly known as ‘Crinklemats.'”

Crinklemats, flowering plants of the genus Tiquilia, grow low to the ground and feature ridged, hairy leaves and small, trumpet-shaped blue blossoms.

“Like the bees, Tiquilia flowers are very small,” Portman says. “The bees must squeeze into the long, narrow corollas and dunk their heads into the flowers to extract the pollen.”

The scientists report the female bees use pollen collected from the flowers to build up a supply to nourish their young. Once they have completed a pollen provision, the bees lay their eggs on the stash and leave their offspring to fend for themselves.

Portman says the bees have developed a special adaptation called a “hair basket,” with inward-facing, hooked hairs, that allows them to collect pollen as they dive into a flower.

“We don’t yet know if the bees use their legs to scoop pollen into the basket or if they simply collect it using their heads,” he says. “There’s still a lot of unknowns.”

Portman says understanding more about these adaptations between the bees and the flowers they pollinate may be critical to the preservation of their surrounding environment.

Beyond their role as pollinators, he says the bees are interesting from an ecological and evolutionary standpoint due to their adaptations to arid habitats and high contrast colour patterns.

“Some of the bees feature stripes and others have spots, which could be patterns for camouflage or a form of mimicry,” Portman says. “These are characteristics we’re still exploring.”

Much of what Portman and his colleagues know about bees of the Perdita genus is built upon the work of the late University of California, Riverside entomologist Phillip Hunter Timberlake. Born in 1883, Timberlake described and named more than 800 bee species during his astounding 70-year career.

“Timberlake was considered eccentric, but his scholarship is to be admired,” Portman says. “Although identifying Perdita and finding the bees’ nests is challenging, these bees have a lot to tell us about adaptation to a harsh and inhospitable environment.”


 

All Fours

It is not entirely true that we humans walk with our feet. Walking, as part of locomotion, is a coordinated whole-body movement that involves both the arms and legs. Researchers at the Biozentrum of the University of Basel and the Friedrich Miescher Institute for Biomedical Research have identified different subpopulations of neurons in the spinal cord with long projections. Published in Neuron, the results show that these neurons coordinate movement of arms and legs and ensure a stable body posture during locomotion.

The locomotor pattern consists of a highly controlled sequence of muscle contractions, which are controlled by neuronal circuits in the spinal cord and the brain. The research group of Prof. Silvia Arber at the Biozentrum of the University of Basel and the Friedrich Miescher Institute for Biomedical Research now reveal that specific, long projecting neurons, traversing our spinal cord, form an important basis for the coordination of fore- and hindlimbs. These neurons couple local networks over long distances and thereby ensure posture and rhythm of our body during locomotion.

Even though humans rose from the quadrupedal position to stand on their feet during evolution, coordination and alternation patterns of the four limbs are still needed in order to move efficiently as in all other quadrupedal species. “We showed that the diametric movement of fore- and hindlimbs is reflected in neuronal circuits of the spinal cord,” says Ludwig Ruder, first author of the study. Thus, axons of most excitatory neurons cross the midline of the spinal cord and contact contralateral networks. In contrast, inhibitory neurons project predominantly on the same side of the body. The diagonal and mirrored pattern of the excitatory neuronal connections is very interesting when observing the coordination of arms and legs in a runner as Usain Bolt. “During running, not only do his legs move, but synchronously and diametrically also his arms — in complete coordination with each other,” says Ruder.

To demonstrate the importance of long projection neurons in the spinal cord for the walking pattern, the researchers selectively eliminated those neurons. “Upon inactivation of spinal long projection neurons that couple local networks, not only is the stability and speed during running impaired, but also the coordinated fore- and hindlimb movements fall apart at higher speeds,” says Ruder. Interestingly, local movement patterns within a single limb remain however unaffected. This reinforces the specific role of long projecting neurons in the regulation of whole body movement.

In a next step, the research team observed that the neurons with long projections broadcast their signals throughout the spinal cord and receive extensive input from various brain regions. This organization of long projection neurons and their connections places them at an important intersection between integrating information from the brain and distributing it in the spinal cord.

Up to now, researchers investigated mainly local spinal networks and their role in movement. In contrast, neurons with long projections have not been studied all that much. “However, the results of our new study show that long projecting neurons in the spinal cord exhibit a very important role for the coordination of the locomotor pattern,” explains Silvia Arber. “Henceforth, we plan to investigate how the brain interacts differently with local and long projecting spinal neurons to control them specifically.” In the long run, these results can be important to restore functionality after spinal cord injuries.