New Whipray Species Identified by Its DNA

July 29, 2013 — Biologists have analysed tissue samples of 115 spotted whiprays of the Himantura genus, collected in various parts of the Indio-Pacific region. By means of genetic markers -- as opposed to morphological criteria only -- the scientists were able to describe these leopard-skin whiprays in detail and demonstrate that they are isolated from each other in terms of reproduction. They have also discovered a new species that they call Himantura tutul, which belongs to a genetic line that is totally distinct from the three other species that are known in the same group:H. leoparda, H. uarnak and H. undulata. They frequent the same costal habitats but occupy different ecological niches.

Biologists have discovered a new species of whipray that they call Himantura tutul, which belongs to a genetic line that is totally distinct from the three other species that are known in the same group: H. leoparda, H. uarnak and H. undulata. They frequent the same costal habitats but occupy different ecological niches. (Credit: © IRD / P. Laboute)

Distinguish in order to protect

These studies should help to assess the state of these whipray populations and improve their conservation. Knowing the biological characteristics of each species will for instance help to redefine a minimum size for fishing purposes to avoid the catching of juveniles that belong to the larger species. Determining their geographical distribution and habitats will also make it possible to protect the breeding and nursery habitats of each species.

Economical and ecological interest

Ocellated whiprays can grow over 1.50 metres wide. These large animals start breeding fairly late, at the age of 5 or 10 years, and only in small numbers. Their populations are therefore very vulnerable. Fished for food and especially for their skin that is sold to tanneries in South-East Asia, they are threatened almost throughout the tropical Indo-West Pacific. Their overfishing will in time jeopardise a whole segment of the economy in Indonesia, which is the largest shark and whipray exploiter with 30% of all catches worldwide. In less than twenty years, the amount fished in the Java Sea has been divided by ten! As high-level predators, whiprays also play an important role in regulating ecosystems. Their extinction will threaten the functioning of coastal marine environments.

The International Union for Conservation of Nature (IUCN) estimates that 36% of the 650 ray species known in the world are at risk of becoming extinct, including leopard whiprays that are classified as "vulnerable." A better identification of these singular animals is the first vital step towards their conservation.

Did you know?

Ocellated whiprays have one or two venom glands at the base of their tail to protect them against their natural predators, namely sharks and killer whales. Their sting is painful and potentially infectious, with serious consequences if not treated correctly.

Cockatoos Know What Is Going On Behind Barriers

July 29, 2013 — How do you know that the cookies are still there even though they have been placed out of your sight into the drawer? How do you know when and where a car that has driven into a tunnel will reappear? The ability to represent and to track the trajectory of objects, which are temporally out of sight, is highly important in many aspects but is also cognitively demanding. Alice Auersperg and her team from the University of Vienna and Oxford show that "object permanence" abilities in a cockatoo rivals that of apes and four-year-old humans.

The researchers published their findings in the journal Journal of Comparative Psychology.

For investigating spatial memory and tracking in animals and human infants a number of setups have been habitually used. These can roughly be subdivided depending on what is being moved: a desired object (food reward), the hiding places for this object or the test animal itself: In the original invisible displacement tasks, designed by French psychologist Jean Piaget in the 50s, the reward is moved underneath a small cup behind one or more bigger screens and its contents is shown in between visits: if the cup is empty we know that the reward must be behind the last screen visited. Humans solve this task after about two years of age, whereas in primates only the great apes show convincing results.

Likely to be even more challenging in terms of attention, are "Transposition" tasks: the reward is hidden underneath one of several equal cups, which are interchanged one or more times. Human children struggle with this task type more than with the previous and do not solve it reliably before the age of three to four years whereas adult apes solve it but have more trouble with double than single swaps.

In "Rotation" tasks several equal cups, one bearing a reward are aligned in parallel on a rotatable platform, which is rotated at different angles. "Translocation" tasks are similar except that the cups are not rotated but the test animal is carried around the arrangement and released at different angles to the cup alignment. Children find Translocation tasks easier than Rotation tasks and solve them at two to three years of age.

A team of international Scientists tested eight Goffin cockatoos (Cacatua goffini), a conspicuously inquisitive and playful species on visible as well as invisible Piagetian object displacements and derivations of spatial transposition, rotation and translocation tasks. 

Birgit Szabo, one of the experimenters from the University of Vienna, says: "The majority of our eight birds readily and spontaneously solved Transposition, Rotation and Translocation tasks whereas only two out of eight choose immediately and reliably the correct location in the original Piagetian invisible displacement task in which a smaller cup is visiting two of three bigger screens."

Alice Auersperg, the manager of the Goffin Lab who was also one of the experimenters, explains: "Interestingly and just opposite to human toddlers our cockatoos had more problems solving the Piagetian invisible displacements than the transposition task with which children struggle until the age of four. Transpositions are highly demanding in terms of attention since two occluding objects are moved simultaneously. Nevertheless, in contrast to apes, which find single swaps easier than double the cockatoos perform equally in both conditions."

Similarly, Goffins had little complications with Rotations and Translocation tasks and some of them solved them at four different angles. Again, in contrast to children, which find Translocations easier than Rotations, the cockatoos showed no significant differences between the two tasks. 

Auguste von Bayern from the University of Oxford adds: " We assume that the ability to fly and prey upon or being preyed upon from the air is likely to require pronounced spatial rotation abilities and may be a candidate trait influencing the animals' performance in rotation and translocation tasks."

Thomas Bugnayer from the University of Vienna concludes: "Finding that Goffins solve transposition, rotation and translocation tasks, which are likely to pose a large cognitive load on working memory, was surprising and calls for more comparative data in order to better understand the relevance of such accurate tracking abilities in terms of ecology and sociality."

 

Borneo's Orangutans Are Coming Down from the Trees; Behavior May Show Adaptation to Habitat Change

July 29, 2013 — Orangutans might be the king of the swingers, but primatologists in Borneo have found that the great apes spend a surprising amount of time walking on the ground. The research, published in theAmerican Journal of Primatology found that it is common for orangutans to come down from the trees to forage or to travel, a discovery which may have implications for conservation efforts.

An expedition led by Brent Loken from Simon Fraser University and Dr. Stephanie Spehar from the University of Wisconsin Oshkosh, travelled to the East Kalimantan region of Borneo. The region's Wehea Forest is a known biodiversity hotspot for primates, including the Bornean orangutan subspecies, Pongo pygmaeus morio, the least studied of orangutan subspecies.

"Orangutans are elusive and one reason why recorded evidence of orangutans on the ground is so rare is that the presence of observers inhibits this behaviour," said Loken. "However, with camera traps we are offered a behind the scenes glimpse at orangutan behaviour."

The team positioned ground-based cameras across a 38-square-kilometre region of the forest and succeeded in capturing the first evidence of orangutans regularly coming down from the trees. The amount of time orangutans spent on the forest floor was found to be comparable to the ground-dwelling pig-tailed macaque, Macaca nemestrina, which is equally abundant in Wehea Forest. Over 8-months orangutans were photographed 110 times, while the macaques were photographed 113 times.

The reason orangutans come down from the trees remains a mystery. However, while the absence of large predators may make it safer to walk on the forest floor, a more pressing influence is the rapid and unprecedented loss of Borneo's orangutan habitat.

"Borneo is a network of timber plantations, agro-forestry areas and mines, with patches of natural forest," said Loken. "The transformation of the landscape could be forcing orangutans to change their habitat and their behaviour."

This research helps to reveal how orangutans can adapt to their changing landscape; however, this does not suggest they can just walk to new territory if their habitat is destroyed. The orangutan subspecies P. p. morio may be adapted to life in more resource scarce forests, having evolved larger jaws which allow them to consume more tree bark and less fruit but they are still dependent on natural forests for their long term survival.

"While we're learning that orangutans may be more behaviourally flexible than we thought and that some populations may frequently come to the ground to travel, they still need forests to survive," said Dr. Spehar. "Even in forest plantation landscapes they rely heavily on patches of natural forest for food resources and nesting sites."

Wehea Forest is one of the only places in Borneo where ten primates species, including five species found only in Borneo, overlap in their ranges. Since Wehea Forest is a biodiversity hotspot, paperwork have been submitted to legally change the status of Wehea Forest from "production forest" to "protected forest." However, given that 78% of wild orangutans live outside of protected areas, it is critical that all of Borneo's remaining forests are either protected or sustainably managed.

"We do not know how long this may take, but protecting Wehea Forest and Borneo's remaining forests is vital to the long term survival of the orangutans," concluded Loken. "Fortunately 60% of Wehea Forest falls under Indonesia's logging moratorium, which helps give legal protection to a large part of the forest for a few more years."

 

Mechanism Behind Squids' and Octopuses' Ability to Change Color Revealed

uly 25, 2013 — Color in living organisms can be formed two ways: pigmentation or anatomical structure. Structural colors arise from the physical interaction of light with biological nanostructures. A wide range of organisms possess this ability, but the biological mechanisms underlying the process have been poorly understood.

Two years ago, an interdisciplinary team from UC Santa Barbara discovered the mechanism by which a neurotransmitter dramatically changes color in the common market squid, Doryteuthis opalescens. That neurotransmitter, acetylcholine, sets in motion a cascade of events that culminate in the addition of phosphate groups to a family of unique proteins called reflectins. This process allows the proteins to condense, driving the animal's color-changing process.

Now the researchers have delved deeper to uncover the mechanism responsible for the dramatic changes in color used by such creatures as squids and octopuses. The findings -- published in the Proceedings of the National Academy of Science, in a paper by molecular biology graduate student and lead author Daniel DeMartini and co-authors Daniel V. Krogstad and Daniel E. Morse -- are featured in the current issue of The Scientist.

Structural colors rely exclusively on the density and shape of the material rather than its chemical properties. The latest research from the UCSB team shows that specialized cells in the squid skin called iridocytes contain deep pleats or invaginations of the cell membrane extending deep into the body of the cell. This creates layers or lamellae that operate as a tunable Bragg reflector. Bragg reflectors are named after the British father and son team who more than a century ago discovered how periodic structures reflect light in a very regular and predicable manner.

"We know cephalopods use their tunable iridescence for camouflage so that they can control their transparency or in some cases match the background," said co-author Daniel E. Morse, Wilcox Professor of Biotechnology in the Department of Molecular, Cellular and Developmental Biology and director of the Marine Biotechnology Center/Marine Science Institute at UCSB.

"They also use it to create confusing patterns that disrupt visual recognition by a predator and to coordinate interactions, especially mating, where they change from one appearance to another," he added. "Some of the cuttlefish, for example, can go from bright red, which means stay away, to zebra-striped, which is an invitation for mating."

The researchers created antibodies to bind specifically to the reflectin proteins, which revealed that the reflectins are located exclusively inside the lamellae formed by the folds in the cell membrane. They showed that the cascade of events culminating in the condensation of the reflectins causes the osmotic pressure inside the lamellae to change drastically due to the expulsion of water, which shrinks and dehydrates the lamellae and reduces their thickness and spacing. The movement of water was demonstrated directly using deuterium-labeled heavy water.

When the acetylcholine neurotransmitter is washed away and the cell can recover, the lamellae imbibe water, rehydrating and allowing them to swell to their original thickness. This reversible dehydration and rehydration, shrinking and swelling, changes the thickness and spacing, which, in turn, changes the wavelength of the light that's reflected, thus "tuning" the color change over the entire visible spectrum.

"This effect of the condensation on the reflectins simultaneously increases the refractive index inside the lamellae," explained Morse. "Initially, before the proteins are consolidated, the refractive index -- you can think of it as the density -- inside the lamellae and outside, which is really the outside water environment, is the same. There's no optical difference so there's no reflection. But when the proteins consolidate, this increases the refractive index so the contrast between the inside and outside suddenly increases, causing the stack of lamellae to become reflective, while at the same time they dehydrate and shrink, which causes color changes. The animal can control the extent to which this happens -- it can pick the color -- and it's also reversible. The precision of this tuning by regulating the nanoscale dimensions of the lamellae is amazing."

Another paper by the same team of researchers, published in Journal of the Royal Society Interface, with optical physicist Amitabh Ghoshal as the lead author, conducted a mathematical analysis of the color change and confirmed that the changes in refractive index perfectly correspond to the measurements made with live cells.

A third paper, in press at Journal of Experimental Biology, reports the team's discovery that female market squid show a set of stripes that can be brightly activated and may function during mating to allow the female to mimic the appearance of the male, thereby reducing the number of mating encounters and aggressive contacts from males. The most significant finding in this study is the discovery of a pair of stripes that switch from being completely transparent to bright white.

"This is the first time that switchable white cells based on the reflectin proteins have been discovered," Morse noted. "The facts that these cells are switchable by the neurotransmitter acetylcholine, that they contain some of the same reflectin proteins, and that the reflectins are induced to condense to increase the refractive index and trigger the change in reflectance all suggest that they operate by a molecular mechanism fundamentally related to that controlling the tunable color."

Could these findings one day have practical applications? "In telecommunications we're moving to more rapid communication carried by light," said Morse. "We already use optical cables and photonic switches in some of our telecommunications devices. The question is -- and it's a question at this point -- can we learn from these novel biophotonic mechanisms that have evolved over millions of years of natural selection new approaches to making tunable and switchable photonic materials to more efficiently encode, transmit, and decode information via light?"

In fact, the UCSB researchers are collaborating with Raytheon Vision Systems in Goleta to investigate applications of their discoveries in the development of tunable filters and switchable shutters for infrared cameras. Down the road, there may also be possible applications for synthetic camouflage.

Other members of the UCSB interdisciplinary research team involved in these discoveries include Elizabeth Eck, Erica Pandolfi, Aaron T. Weaver, and Mary Baum.

This research was supported by the Office of Naval Research via a Multidisciplinary University Research Initiative award and an Army Research Office grant through UCSB's Institute for Collaborative Biotechnologies. As well, use was made of UCSB Materials Research Laboratory central facilities and equipment, which are supported by a grant from the National Science Foundation.

Using Earthquake Sensors to Track Endangered Whales

May 13, 2013 — The fin whale is the second-largest animal ever to live on Earth. It is also, paradoxically, one of the least understood. The animal's huge size and global range make its movements and behavior hard to study.

CLICK FOR VIDEO

A carcass that washed up on a Seattle-area beach this spring provided a reminder that sleek fin whales, nicknamed "greyhounds of the sea," are vulnerable to collision when they strike fast-moving ships. Knowing their swimming behaviors could help vessels avoid the animals. Understanding where and what they eat could also help support the fin whale's slowly rebounding populations.

University of Washington oceanographers are addressing such questions using a growing number of seafloor seismometers, devices that record vibrations. A series of three papers published this winter in the Journal of the Acoustical Society of America interprets whale calls found in earthquake sensor data, an inexpensive and non-invasive way to monitor the whales. The studies are the first to match whale calls with fine-scale swimming behavior, providing new hints at the animals' movement and communication patterns.

The research began a decade ago as a project to monitor tremors on the Juan de Fuca Ridge, a seismically active zone more than a mile deep off the Washington coast. That was the first time UW researchers had collected an entire year's worth of seafloor seismic data.

"Over the winter months we recorded a lot of earthquakes, but we also had an awful lot of fin-whale calls," said principal investigator William Wilcock, a UW professor of oceanography. At first the fin whale calls, which at 17 to 35 vibrations per second overlap with the seismic data, "were kind of just a nuisance," he said.

In 2008 Wilcock got funding from the Office of Naval Research to study the previously discarded whale calls.

Dax Soule, a UW doctoral student in oceanography, compared the calls recorded by eight different seismometers. Previous studies have done this for just two or three animals at a time, but the UW group automated the work to analyze more than 300,000 whale calls. The method is similar to how a smartphone's GPS measures a person's location by comparing paths to different satellites. Researchers looked at the fin whale's call at the eight seismometers to calculate a position. That technique let them follow the animal's path through the instrument grid and within 10 miles of its boundaries.

Soule created 154 individual fin whale paths and discovered three categories of vocalizing whales that swam south in winter and early spring of 2003. He also found a category of rogue whales that traveled north in the early fall, moving faster than the other groups while emitting a slightly higher-pitched call.

"One idea is that these are juvenile males that don't have any reason to head south for the breeding season," Soule said. "We can't say for sure because so little is known about fin whales. To give you an idea, people don't even know how or why they make their sound."

The fin whale's call is not melodic, but that's a plus for this approach. The second-long chirp emitted roughly every 25 seconds is consistently loud and at the lower threshold of human hearing, so within range of earthquake monitoring instruments. These loud, repetitive bleeps are ideally suited for computer analysis.

Michelle Weirathmueller, a UW doctoral student in oceanography, used Soule's triangulations to determine the loudness of the call. She found the fin whale's call is surprisingly consistent at 190 decibels, which translates to 130 decibels in air -- about as loud as a jet engine.

Knowing the consistent amplitude of the fin whale's song will help Weirathmueller track whales with more widely spaced seismometer networks, in which a call is recorded by only one instrument at a time. Those include the Neptune Canada project, the U.S. cabled observatory component of the Ocean Observatories Initiative, and the huge 70-seismometer Cascadia Initiative array that's begun to detect tremors off the Pacific Northwest coast.

"We'd like to know where the fin whales are at any given time and how their presence might be linked to food availability, ocean conditions and seafloor geology," Weirathmueller said. "This is an incredibly rich dataset that can start to pull together the information we need to link the fin whales with their deep-ocean environments."

Seabird Bones Reveal Changes in Open-Ocean Food Chain

May 13, 2013 — Remains of endangered Hawaiian petrels -- both ancient and modern -- show how drastically today's open seas fish menu has changed.

A research team, led by Michigan State University and Smithsonian Institution scientists, analyzed the bones of Hawaiian petrels -- birds that spend the majority of their lives foraging the open waters of the Pacific. They found that the substantial change in petrels' eating habits, eating prey that are lower rather than higher in the food chain, coincides with the growth of industrialized fishing.

The birds' dramatic shift in diet, shown in the current issue of the Proceedings of the National Academy of Sciences, leaves scientists pondering the fate of petrels as well as wondering how many other species face similar challenges.

"Our bone record is alarming because it suggests that open-ocean food webs are changing on a large scale due to human influence," said Peggy Ostrom, co-author and MSU zoologist. "Our study is among the first to address one of the great mysteries of biological oceanography -- whether fishing has gone beyond an influence on targeted species to affect nontarget species and potentially, entire food webs in the open ocean."

Hawaiian petrels' diet is recorded in the chemistry of their bones. By studying the bones' ratio of nitrogen-15 and nitrogen-14 isotopes, researchers can tell at what level in the food chain the birds are feasting; generally, the larger the isotope ratio, the bigger the prey (fish, squid and crustaceans).

Between 4,000 and 100 years ago, petrels had high isotope ratios, indicating they ate bigger prey. After the onset of industrial fishing, which began extending past the continental shelves around 1950, the isotope ratios declined, indicating a species-wide shift to a diet of smaller fish and other prey.

Much research has focused on the impact of fishing near the coasts. In contrast, the open ocean covers nearly half of Earth's surface. But due to a lack of historical records, fishing's impact on most open-ocean animal populations is completely unknown, said lead author Anne Wiley, formerly an MSU doctoral student and now a Smithsonian postdoctoral researcher.

"Hawaiian petrels spend the majority of their lives foraging over vast expanses of open ocean," she said. "In their search for food, they've done what scientists can only dream of. For thousands of years, they've captured a variety of fish, squid and crustaceans from a large portion of the North Pacific Ocean, and a record of their diet is preserved in their bones."

Addressing fishery impact through a chronology of bones is remarkable. Most marine animals die at sea, where their bones are buried on the ocean bottom. But after three decades of fossil collection in the Hawaiian Islands -- the breeding grounds of the Hawaiian petrel -- co-author Helen James of the Smithsonian Institution and her colleagues have amassed a collection of more than 17,000 ancient Hawaiian petrel bones.

"The petrels breed in burrows and caves where, if they die, their bones are likely to be preserved for a long time," James said. "It's fortuitous to find such a rich bone record for a rare oceanic predator."

Further studies are needed to explore how the shift down the food chain is affecting Hawaiian petrels. For a coastal seabird, however, a similar shift in diet has been associated with decreases in population -- bad news for a federally protected bird.

Since petrels exploit fishing grounds from the equator to near the Aleutian Islands -- an area larger than the continental United States -- their foraging habits are quite telling. If petrels, signal flares for open-ocean food webs, have had a species-wide change in feeding habits, how many other predators around the world has fishing impacted? And what role do consumers play?

"What you choose to put on your dinner plate -- that's your connection with the endangered Hawaiian petrel, and with many other marine species," Wiley said.

The research was funded by the National Science Foundation, MSU and the Smithsonian Institution.

Biologists Race to Save Nearly Extinct Florida Bird

19 April 2013 - Even though the project didn't snag a hoped-for grant, federal officials said Thursday they have decided to proceed with plans to collect eggs from the nests of one of the most endangered species in North America — the Florida grasshopper sparrow — in hopes of preventing its extinction.

Researchers fear the small, elusive bird, now clinging to survival in three Central Florida parklands, could vanish within a few years.

U.S. Fish and Wildlife Service officials said the captive-breeding program will consist of volunteers and staff from their agency, the state Fish and Wildlife Conservation Commission and the state Park Service. Teams will attempt to collect eggs through early summer, taking them to the Rare Species Conservatory Foundation in Loxahatchee.

Hatchlings will be kept in captivity in a years-long effort to establish a population of birds that eventually could help bolster the health of sparrows still existing in the wild — or serve as pioneers in re-establishing a wild population should the current one go extinct.

Several university and private researchers have criticized the federal agency, harshly in some cases, for giving the sparrows a low priority as their numbers dipped alarmingly and inexplicably in recent years. The birds rely on vast, treeless prairies, but much of that habitat has been paved by development or plowed under by agriculture.

Researchers are vexed by the birds' decline in part because the public lands where they still exist, including Three Lakes Wildlife Management Area and Kissimmee Prairie Preserve State Park, have been intensively managed to suit the sparrows' needs. Invading fire ants are suspected to play a role in the decline.

The Fish and Wildlife Service said it will cobble together dollars from various sources to support further research and the captive-breeding work.

Ocean Acidification as a Hearing Aid for Fish?

Apr. 19, 2013 — Ocean acidification, which occurs as CO₂ is absorbed by the world's oceans, is a source of concern for marine scientists worldwide. Studies on coral, mollusks, and other ocean denizens are helping to paint a picture of what the future might entail for specific species, should carbon emissions continue to increase.

In a new study published in Global Change Biology, University of Miami (UM) Rosenstiel School of Marine & Atmospheric Science researchers Sean Bignami, Su Sponaugle, and Robert Cowen are the first to study the effects of acidification on the larvae of cobia (Rachycentron canandum). Cobia are large tropical fish that spawn in pelagic waters, highly mobile as they mature, and a popular species among recreational anglers.

The team reared cobia in tanks with different levels of CO₂ saturation looking for effects on growth, development, otolith (ear stone) formation, swimming ability, and activity level during the vulnerable larval stage of these fish. 

They found that cobia showed remarkable resistance to end-of-century acidification scenarios in terms of growth, development, and activity. However, more extreme acidification scenarios caused reduced larval size and a 2-3 day delay in their development. The study also reports a significant increase in otolith size at the most mild acidification conditions reported to date.

"The larval period is a critical stage in the marine fish lifecycle and the ability of cobia larvae to withstand 'business-as-usual' scenarios of ocean acidification provides an optimistic outlook for this species. However, research on this topic is still limited and if our findings on otolith formation are any indicator, then these fish are not entirely resistant to acidification," said Bignami, a Marine Biology and Fisheries PhD candidate at UM.

The study is the first to report impacts of ocean acidification on a large, pelagic tropical fish species. 

"We need additional studies on study how fish, especially those that are ecologically and economically important, react to these environmental changes if we want to find ways to potentially mitigate the effects," Bignami added.

Cobia larvae used in this study were produced from broodstock raised at the UM Experimental Hatchery.

Scientists Reverse Memory Loss in Animal Brain Cells

Apr. 17, 2013 — Neuroscientists at The University of Texas Health Science Center at Houston (UTHealth) have taken a major step in their efforts to help people with memory loss tied to brain disorders such as Alzheimer's disease.

Using sea snail nerve cells, the scientists reversed memory loss by determining when the cells were primed for learning. The scientists were able to help the cells compensate for memory loss by retraining them through the use of optimized training schedules. Findings of this proof-of-principle study appear in the April 17 issue ofThe Journal of Neuroscience.

"Although much works remains to be done, we have demonstrated the feasibility of our new strategy to help overcome memory deficits," said John "Jack" Byrne, Ph.D., the study's senior author, as well as director of the W.M. Keck Center for the Neurobiology of Learning and Memory and chairman of the Department of Neurobiology and Anatomy at the UTHealth Medical School.

This latest study builds on Byrne's 2012 investigation that pioneered this memory enhancement strategy. The 2012 study showed a significant increase in long-term memory in healthy sea snails called Aplysia californica, an animal that has a simple nervous system, but with cells having properties similar to other more advanced species including humans.

Yili Zhang, Ph.D., the study's co-lead author and a research scientist at the UTHealth Medical School, has developed a sophisticated mathematical model that can predict when the biochemical processes in the snail's brain are primed for learning.

Her model is based on five training sessions scheduled at different time intervals ranging from 5 to 50 minutes. It can generate 10,000 different schedules and identify the schedule most attuned to optimum learning.

"The logical follow-up question was whether you could use the same strategy to overcome a deficit in memory," Byrne said. "Memory is due to a change in the strength of the connections among neurons. In many diseases associated with memory deficits, the change is blocked."

To test whether their strategy would help with memory loss, Rong-Yu Liu, Ph.D., co-lead author and senior research scientist at the UTHealth Medical School, simulated a brain disorder in a cell culture by taking sensory cells from the sea snails and blocking the activity of a gene that produces a memory protein. This resulted in a significant impairment in the strength of the neurons' connections, which is responsible for long-term memory.

To mimic training sessions, cells were administered a chemical at intervals prescribed by the mathematical model. After five training sessions, which like the earlier study were at irregular intervals, the strength of the connections returned to near normal in the impaired cells.

"This methodology may apply to humans if we can identify the same biochemical processes in humans. Our results suggest a new strategy for treatments of cognitive impairment. Mathematical models might help design therapies that optimize the combination of training protocols with traditional drug treatments," Byrne said.

He added, "Combining these two could enhance the effectiveness of the latter while compensating at least in part for any limitations or undesirable side effects of drugs. These two approaches are likely to be more effective together than separately and may have broad generalities in treating individuals with learning and memory deficits."

Other co-authors from the UTHealth Medical School included: Douglas A. Baxter, Ph.D., professor; Paul Smolen, Ph.D., assistant professor; and Len Cleary, Ph.D., professor.

Love at First Sniff: Male Moths Go by First Impressions

Apr. 16, 2013 — An international team of researchers, including an entomologist at the University of California, Riverside, has an explanation for why we see so many hybrid moths in nature. The team closely examined the behavior and the olfactory circuitry of male moths and found an answer in female-produced pheromones -- chemicals generally consisting of a blend of two to several derivatives of fatty acids.

Male moths use pheromones to find females. To avoid mating with the wrong moth species, the pheromone blends are specific for each moth species, with only males of the same species "understanding" these volatile messages -- a result shown many times during the last 40 years of research on moth pheromones. The researchers focused on the European corn borer, a moth species in which males often mate with females from a different strain.

Strains are variants, forms of the same species. While two different species cannot mate with each other, strains, being from the same species, can.

To understand the mating behavior of the European corn borer, first, the researchers followed the flights of males to female pheromones in a wind tunnel. Each strain of the European corn borer uses a blend of pheromone components in a very specific ratio. But to their surprise, the researchers found that as the male moth flies upwind along the pheromone plume, its olfactory circuitry loses the ability to measure this ratio.

"This happens because receptors in the moth brain for each pheromone component have differential rates of sensory adaptation and each type of receptor begins to fire at a different rate, causing the input into the moth's brain to change as the moth flies along the plume," explained Teun Dekker, a former UCR graduate student and now an associate professor at the Swedish University of Agricultural Sciences, and a coauthor on the study. "To overcome this mismatch, moths rely on the ratio they detected in their first encounter with the plume."

According to the researchers, this "mental short cut" is needed for male moths to continue their orientation along the plumes which, from a sensory input viewpoint, seem to be changing in pheromone component ratio.

"Once male moths lock onto a pheromone plume, they are much less attuned to blend quality," Dekker said. "In other words, males fly even to blends that were initially unattractive, and so can mate with females of different strains that they would not have approached otherwise, explaining why we find hybrid moths in nature."

Study results appeared online April 15 in the Proceedings of the National Academy of Sciences.

Experimental details

The researchers conducted a series of behavioral experiments with overlapping pheromone plumes as well as plumes that sharply transitioned from one blend to another in a wind tunnel at the Swedish University of Agricultural Sciences. They chose the European corn borer moth to study for its narrow tuning to a binary blend of female-produced 14-carbon-chainlength acetates, called here Z11 and E11 for simplicity. Two strains exist, the Z and E strains, which produce and prefer blends of differing ratios of the Z11 to E11 pheromone components.

The researchers installed pheromone lures of each strain in the wind tunnel, as well as an intermediate, hybrid lure. Next they exposed males to the partially overlapping pheromone plumes released by these lures, thus mimicking plumes occurring in nature when a large number of moths are present.

They found that males were initially attracted to lures releasing pheromones produced by females of their own strain. But after taking flight, the males "relax their specificity," that is, they are less particular about which lures they fly to. For example, in a choice between three partially overlapping pheromone sources in one experiment, 58 percent, 38 percent and 4 percent of Z-strain males landed on Z, H and E lures, respectively.

"What we generally recognize as a distinctive smell -- the scent of a flower or the aroma of coffee -- typically consists of a mixture of many different chemicals," said study coauthor Ring Cardé, a distinguished professor of entomology who holds the Alfred M. Boyce Chair in the UCR Department of Entomology. "This is the signature of a particular bouquet -- the presence of a blend of many chemicals often in specific ratios. Our work suggests that it could be the first impression -- the first whiff of odor -- that determines the ability of an insect to recognize that odor mixture."

Next, the researchers will examine if a response specific to odor blends is altered in other moth species and organisms such as mosquitoes after their first encounter with an odor mixture.

Zsolt Kárpáti at the Hungarian Academy of Sciences and Marco Tasin at the Swedish University of Agricultural Sciences also contributed to the study. Dekker worked in Cardé's lab, graduating from UCR with a doctoral degree in 2002.

Cardé, who spent three months in 2011 in Sweden to conduct the research, was supported by a grant from the Swedish Royal Academy of Natural Sciences, Medicine and Technology.

Alternative Way to Explain Life's Complexity Proposed

Apr. 12, 2013 — Evolution skeptics argue that some biological structures, like the brain or the eye, are simply too complex for natural selection to explain. Biologists have proposed various ways that so-called 'irreducibly complex' structures could emerge incrementally over time, bit by bit. But a new study proposes an alternative route.

Instead of starting from simpler precursors and becoming more intricate, say authors Dan McShea and Wim Hordijk, some structures could have evolved from complex beginnings that gradually grew simpler -- an idea they dub "complexity by subtraction."       Computer models and trends in skull evolution back them up, the researchers show in a study published this week in the journalEvolutionary Biology.

Some biological structures are too dizzyingly complex to have emerged stepwise by adding one part and then the next over time, intelligent design advocates say. Consider the human eye, or the cascade that causes blood to clot, or the flagellum, the tiny appendage that enables some bacteria to get around. Such all-or-none structures, the argument goes, need all their parts in order to function. Alter or take away any one piece, and the whole system stops working. In other words, what good is two thirds of an eye, or half of a flagellum?

For the majority of scientists, the standard response is to point to simpler versions of supposedly 'irreducibly complex' structures that exist in nature today, such as cup eyes in flatworms. Others show how such structures could have evolved incrementally over millions of years from simpler precursors. A simple eye-like structure -- say, a patch of light-sensitive cells on the surface of the skin -- could evolve into a camera-like eye like what we humans and many other animals have today, biologists say.

"Even a very simple eye with a small number of parts would work a little. It would be able to detect shadows, or where light is coming from," said co-author Dan McShea of Duke University.

In a new study, McShea and co-author Wim Hordijk propose an alternative route. Instead of emerging by gradually and incrementally adding new genes, cells, tissues or organs over time, what if some so-called 'irreducibly complex' structures came to be by gradually losing parts, becoming simpler and more streamlined? Think of naturally occurring rock arches, which start as cliffs or piles of stone and form when bits of stone are weathered away. They call the principle 'complexity by subtraction.'

"Instead of building up bit by bit from simple to complex, you start complex and then winnow out the unnecessary parts, refining them and making them more efficient as you go," McShea said.

A computer model used by co-author Wim Hordijk supports the idea. In the model, complex structures are represented by an array of cells, some white and some black, like the squares of a checkerboard. In this class of models known as cellular automata, the cells can change between black and white according to a set of rules.

Using a computer program that mimics the process of inheritance, mutation, recombination, and reproduction, the cells were then asked to perform a certain task. The better they were at accomplishing the task, the more likely they were to get passed on to the next generation, and over time a new generation of rules replaced the old ones. In the beginning, the patterns of black and white cells that emerged were quite complex. But after several more generations, some rules 'evolved' to generate simpler black and white cell patterns, and became more efficient at performing the task, Hordijk said.

We see similar trends in nature too, the authors say. Summarizing the results of previous paleontological studies, they show that vertebrate skulls started out complex, but have grown simpler and more streamlined. 

"For example, the skulls of fossil fish consist of a large number of differently-shaped bones that cover the skull like a jigsaw puzzle," McShea said. "We see a reduction in the number of skull bone types in the evolutionary transitions from fish to amphibian to reptile to mammal." 

In some cases skull bones were lost; in other cases adjacent bones were fused. Human skulls, for example, have fewer bones than fish skulls.

Computer simulations like Hordijk's will allow scientists to test ideas about how often 'complexity by subtraction' happens, or how long it takes. The next step is to find out how often the phenomenon happens in nature.

"What we need to do next is pick an arbitrary sample of complex structures and trace their evolution and see if you can tell which route they proceeded by, [from simple to complex or the opposite]. That will tell us whether this is common or not," McShea added.

Self-Medication in Animals Much More Widespread Than Believed

Apr. 11, 2013 — It's been known for decades that animals such as chimpanzees seek out medicinal herbs to treat their diseases. But in recent years, the list of animal pharmacists has grown much longer, and it now appears that the practice of animal self-medication is a lot more widespread than previously thought, according to a University of Michigan ecologist and his colleagues.

Animals use medications to treat various ailments through both learned and innate behaviors. The fact that moths, ants and fruit flies are now known to self-medicate has profound implications for the ecology and evolution of animal hosts and their parasites, according to Mark Hunter, a professor in the Department of Ecology and Evolutionary Biology and at the School of Natural Resources and Environment.

In addition, because plants remain the most promising source of future pharmaceuticals, studies of animal medication may lead the way in discovering new drugs to relieve human suffering, Hunter and two colleagues wrote in a review article titled "Self-Medication in Animals," to be published online today in the journal Science.

"When we watch animals foraging for food in nature, we now have to ask, are they visiting the grocery store or are they visiting the pharmacy?" Hunter said. "We can learn a lot about how to treat parasites and disease by watching other animals."

Much of the work in this field has focused on cases in which animals, such as baboons and woolly bear caterpillars, medicate themselves. One recent study has suggested that house sparrows and finches add high-nicotine cigarette butts to their nests to reduce mite infestations.

But less attention has been given to the many cases in which animals medicate their offspring or other kin, according to Hunter and his colleagues. Wood ants incorporate an antimicrobial resin from conifer trees into their nests, preventing microbial growth in the colony. Parasite-infected monarch butterflies protect their offspring against high levels of parasite growth by laying their eggs on anti-parasitic milkweed.

Hunter and his colleagues suggest that researchers in the field should "de-emphasize the 'self' in self-medication" and base their studies on a more inclusive framework.

"Perhaps the biggest surprise for us was that animals like fruit flies and butterflies can choose food for their offspring that minimizes the impacts of disease in the next generation," Hunter said. "There are strong parallels with the emerging field of epigenetics in humans, where we now understand that dietary choices made by parents influence the long-term health of their children."

The authors argue that animal medication has several major consequences on the ecology and evolution of host-parasite interactions. For one, when animal medication reduces the health of parasites, there should be observable effects on parasite transmission or virulence.

For example, when gypsy moth caterpillars consume foliage high in certain toxic compounds, transmission of viruses between the caterpillars is reduced, facilitating moth outbreaks.

In addition, animal medication should affect the evolution of animal immune systems, according to Hunter and his colleagues. Honeybees are known to incorporate antimicrobial resins into their nests. Analysis of the honeybee genome suggests that they lack many of the immune-system genes of other insects, raising the possibility that honeybees' use of medicine has been partly responsible -- or has compensated -- for a loss of other immune mechanisms.

The authors also note that the study of animal medication will have direct relevance for human food production. Disease problems in agricultural organisms can worsen when humans interfere with the ability of animals to medicate, they point out.

For example, increases in parasitism and disease in honeybees can be linked to selection by beekeepers for reduced resin deposition by their bees. A reintroduction of such behavior in managed bee colonies would likely have great benefits for disease management, the authors say.

The first author of the Science paper is Jacobus de Roode of Emory University. The other author is Thierry Lefevre of the Institut de Recherche pour le Developpement in France.

Goosefish Capture Small Puffins Over Deep Water of Northwest Atlantic

Apr. 10, 2013 — A recent study has shown that bottom-dwelling goosefish, also known as monkfish, prey on dovekies, a small Arctic seabird and the smallest member of the puffin family. To understand how this deep-water fish finds a shallow-feeding bird in offshore waters, researchers looked at when, where, and how these animals were most likely to be in the same place at the same time.

Remains of fourteen dovekie were recovered from the stomachs of 14 goosefish caught during the winters between 2007 and 2010. The goosefish were captured in gillnets deployed at depths between 275 and 495 feet in waters 65 to 95 miles south of Chatham, Mass. The Cape Cod Commercial Hook Fishermen's Association collected the specimens and provided them for the research study.

Researchers from NOAA's Northeast Fisheries Science Center (NEFSC) in Woods Hole, Mass. and the USGS Patuxent Wildlife Research Center in Laurel, Md., wanted to know how the birds could be captured so far from shore by a fish that lives on the ocean bottom in deep water. Their findings, recently published online in the Northeastern Naturalist, suggest that it is all a matter of timing.

Goosefish (Lophius americanus) are highly opportunistic predators. Distributed from the Gulf of Maine to Cape Hatteras, N.C., the fish are typically partially buried on soft bottom habitats and attract a variety of prey by using a modified dorsal fin ray that resembles a fishing pole and lure.

Dovekies, a small black and white puffin species, breed along the Arctic coast and head south in the winter, typically as far as New England. The dovekie (Alle alle), also known as little auk, is the smallest of the auks. It lives in the open ocean and can dive to depths of more than 100 feet to prey on small fish, crustaceans, and zooplankton.

Study co-author Anne Richards of the NEFSC says tagging studies that she and colleagues have conducted reveal that goosefish swim considerable vertical distances from the bottom to near the surface, especially during their spring and fall migrations onshore and offshore in response to water temperatures and related factors.

Goosefish leave the bottom to use the currents during migration periods or to spawn at the surface. If prey items are encountered during their vertical movements, the goosefish take advantage. Hence, timing may be the key factor in bringing dovekies and goosefish together in the same place.

"Given the common name 'goosefish', it is not surprising to find birds in goosefish stomachs, but it is surprising to find that this predation occurs over deep water, "Richards said. "Goosefish do not actively seek out the dovekies, but when such tasty morsels are available in the water column, the fish are going to consume them."

Another source of data used in the study is the NOAA NEFSC food-habits database, which contains decades of predation information collected from the stomachs of fish that are caught during regular research vessel surveys. While not a particularly good measure of how often or how many birds are eaten by fish, these data confirm that not only goosefish, but also spiny dogfish, Atlantic herring, pollock, Atlantic cod, red hake, and fourspot flounder will eat birds.

Lead author Matthew Perry, a research wildlife biologist at the USGS Patuxtent Wildlife Research Center, says he became interested in goosefish predation when he learned from a sea scalloper on Nantucket that Chatham gillnetters were finding birds inside goosefish stomachs.

"I was studying long-tailed ducks and thought, to avoid being eaten, these birds fly 30 to 50 miles to Nantucket Sound each night and return to the ocean in the morning," said Perry, who studies several species of seaducks. "People ask why don't dovekies fly to Nantucket Sound at night like the long-tailed ducks to avoid goosefish? My explanation is that dovekies have small wings and can't make the routine flight."

"One thing we know is that dovekies cannot dive to the bottom in 300 to 400 feet of water," Perry said. "Goosefish probably come up from the ocean bottom to within 10 to 20 feet of the water surface at night. As dovekies dive for amphipods, small crustaceans, in the morning at first light, goosefish seize the opportunity and might use their 'fishing lure' to simulate one of these prey species by attracting the dovekies with their typical 'sit and wait' behavior."

The magnitude of fish predation on seabirds is poorly understood. Perry says most food habit studies for goosefish have been conducted during summer when the dovekies have migrated north to their Arctic breeding areas; thus, they seldom have been recorded as prey. Perry hopes more telemetry tracking of goosefish will be done in winter when birds are in the area and are potential prey.

As for what's ahead, Richards says ongoing use of electronic tags on goosefish will provide more information on their vertical movements.