Category: Environment

{Across the animal kingdom there is a strong trend for females to be more caring parents. Why? Researchers have now expanded upon previous theories to better explain why mothers and fathers differ in the effort they put into caring for young.}

Across the animal kingdom there is a strong trend for females to be more caring parents. Why? Researchers at the University of Jyväskylä, Finland and the Australian National University have now expanded upon previous theories to better explain why mothers and fathers differ in the effort they put into caring for young. The research done in Finland is funded by the Academy of Finland.

Using mathematical models, the researchers found that if the only initial difference between the sexes is the size of the sex cells they make (sperm by males and eggs by females), evolution does not favor females becoming more attentive parents.

“Although an egg is a much larger parental investment than a tiny sperm, there is no propensity for females to care more as a result,” said Academy Research Fellow, Dr Lutz Fromhage, from the University of Jyväskylä. But he added, “There is, however, also no evolutionary force favouring equal care by both sexes.” This new finding refutes earlier theories that concluded that equal care by both parents will evolve.

Although females tend to care more than males, there is much variation among species. In many fish, for example, only males guard eggs and defend babies, but in mammals females usually care alone. Dr Fromhage said the study, published in Nature Communications, would lead to a more solid theoretical foundation to understand how male and female parental care evolves.

So why do females provide more care? The researchers propose that another process is important: investment in being sexy, hence mating sooner, might trade-off with the ability to provide care efficiently. Taking this balancing act into account, evolution favors ever more care by the initially more-caring sex. Eventually this sex might end up caring alone. “One factor that could set the ball rolling is an inevitable difference in the certainty of parentage of males and females,” said Prof Michael Jennions from the Australian National University, “with many more sperm than eggs, it is often hard for a male to be sure that he is the father. So males might initially care a little less.”

Many researchers have put forward arguments to explain why females care more than males, but this new study provides formal confirmation based on solid maths.

{New insights into the relationship between ultraviolet (UV) filters and hunting methods in snakes is one of the findings of the first major study of visual pigment genes and lenses in snakes.}

Snakes have adapted their vision to hunt their prey day or night. For example, snakes that need good eyesight to hunt during the day have eye lenses that act as sunglasses, filtering out ultraviolet light and sharpening their vision while nocturnal snakes have lenses that allow ultraviolet light through, helping them to see in the dark.

New insights into the relationship between ultraviolet (UV) filters and hunting methods in snakes is one of the findings of the first major study of visual pigment genes and lenses in snakes — published in the advanced online edition of Molecular Biology and Evolution.

The new research was an international collaboration between snake biologists and vision experts led by the David Gower and included fellow Natural History Museum researchers Bruno Simões and Filipa Sampaio. Much of the research, including most of the DNA analyses, was carried out in the Museum’s laboratories.

Scientists have long known that snakes have highly variable sets of rods and cones — the specialised cells in the retina that an animal uses to detect light. But until now, most modern studies of vision in vertebrates (animals with a backbone) have concentrated on mammals, birds and fish.

To see in different colors, animals use visual pigments in their rods and cones that are sensitive to different wavelengths of light. The researchers examined the genes involved in producing the pigments from a broad genomic survey of 69 different species of snakes. What they found was as the genes vary from species to species so does the exact molecular structure of the pigments and the wavelengths of light they absorb.

The new research discovered that most snakes possess three visual pigments and are likely dichromatic in daylight — seeing two primary colours rather than the three that most humans see.

However, it also discovered that snake visual pigment genes have undergone a great amount of adaptation, including many changes to the wavelengths of light that the pigments are sensitive to, in order to suit the diversity of lifestyles that snakes have evolved.

Most snakes examined in the new study are sensitive to UV light, which likely allows them to see well in low light conditions. For light to reach the retina and be absorbed by the pigments, it first travels through the lens of the eye. Snakes with UV-sensitive visual pigments therefore have lenses that let UV light though.

In contrast, the research showed that those snakes that rely on their eyesight to hunt in the daytime, such as the gliding golden tree snake Chrysopelea ornata and the Monypellier snake Malpolon monspessulanus, have lenses that block UV light. As well as perhaps helping to protect their eyes from damage, this likely helps sharpen their sight — in the same way that skiers’ yellow goggles cut out some blue light and improve contrast.

Moreover, these snakes with UV-filtering lenses have tuned the pigments in their retina so that they are no longer sensitive to the short UV light, but absorb longer wavelengths.

All nocturnal species examined (such as N America’s glossy snake Arizona elegans) were found to have lenses that do not filter UV. Some snake species active in daylight also lack a UV-filtering lens, perhaps because they are less reliant on very sharp vision or live in places without very bright light.

By analysing how the pigments have evolved in snakes, the new study concluded also that the most recent ancestor of all living snakes had UV sensitive vision. “The precise nature of the ancestral snake is contentious, but the evidence from vision is consistent with the idea that it was adapted to living in low light conditions on land,” said corresponding author Gower.

{Last month was the warmest month since the late 19th century, according to data from NASA and the Japan Meteorological Agency.}

Three independent agencies have confirmed July 2016 as the warmest month since they started keeping temperature records, the Weather Channel has reported. July is usually the warmest month globally, since the northern hemisphere has more land mass, and land heats up faster and retains more heat than the oceans.

NASA’s Goddard Institute of Space Studies found it topped the previous warmest July on its record, 2011, by 0.1 of a degree Celsius, 0.84 degrees Celsius above average, making it the warmest since 1880. The Japan Meteorological Agency’s found that it was the warmest since 1891, and the Copernicus Climate Change Service in Europe found that it was the warmest since 1979.

NASA and the NOAA announced earlier this year that 2015 had been the warmest year on record to date. Based on temperature graphs so far, climate scientist Gavin Schmidt believes there is a 99 percent chance that 2016 will top it.

{Biologists studying a small, colorful fish in the Mediterranean Sea have discovered a new way in which a female can choose the best father for her offspring. During spawning of the ocellated wrasse, ovarian fluid released with eggs favors sperm from the nest-tending males preferred by the females, limiting fertilization by ‘sneaker’ males.}

Biologists studying a small, colorful fish in the Mediterranean Sea have discovered a new way in which a female can choose the best father for her offspring.

The animal kingdom is full of elaborate traits and behaviors by which females choose mates. Even in species in which the female mates with multiple males, biologists have found evidence of “cryptic female choice” involving mechanisms in the reproductive tract that influence which male’s sperm fertilize the eggs.

The new study, published August 16 in Nature Communications, demonstrates cryptic female choice in a fish, the ocellated wrasse, in which fertilization takes place externally during spawning. The researchers found that something in the ovarian fluid released with the eggs influences which male’s sperm is most likely to fertilize them.

Female ocellated wrasses prefer males that build nests and take care of the fertilized eggs as they develop. But there are other types of males that do not provide parental care and compete to fertilize the eggs a female lays in the nest prepared by a nesting male. Small “sneaker” males hang out around the nest and dart in to release large amounts of sperm when a female is spawning. The females, however, seem to have found a way to thwart the sneaker males by giving an advantage to the nesting male’s sperm.

“The sneaker males release more sperm than the nesting males, and you’d think that would give them a better chance to fertilize the eggs, but there is something in the ovarian fluid that removes that advantage,” said first author Suzanne Alonzo, professor of ecology and evolutionary biology at UC Santa Cruz.

Alonzo’s team conducted fertilization experiments in petri dishes with and without ovarian fluid. Nesting males produce fewer but faster sperm than sneaker males, and the results showed that the presence of ovarian fluid tips the balance such that sperm quality matters more than quantity. The ovarian fluid does not appear to affect sperm from the different male types differently, but generally enhances how fast and straight the sperm swim and the strength of their attraction to the egg. The overall effect is to increase the relative importance of sperm velocity over sperm numbers.

A nesting male cares for the eggs in his nest regardless of the efforts of sneaker males, but the female still has good reasons to prefer that her eggs are fertilized by the nesting male. Nesting males are older and grow more quickly as juveniles than sneaker males, so they may have genetic traits that would be advantageous to their offspring.

“We know that the nesting males grow faster and have survived into their second year, so if either of those has a genetic basis it makes sense that females would prefer their offspring to carry those genes,” Alonzo said.

In evolutionary terms, this means that by favoring nesting males, cryptic female choice in the ocellated wrasse can cause “directional selection” that influences the evolution of male traits. Other researchers studying chinook salmon have found that ovarian fluid can favor genetically compatible sperm, but have not shown directional selection.

“Directional selection is required for cryptic female choice to actually shape male traits,” Alonzo said.

Research on cryptic female choice over the past ten to 20 years has revealed a range of surprising hidden interactions between the sexes in different species. For the many aquatic animals with external fertilization, however, those kinds of interactions had not seemed possible.

“These new results open up a whole new world of possibilities,” Alonzo said. “When we think about why marine species look and act the way they do, part of what we are seeing depends on this cryptic level of interactions between males and females, or really between eggs and sperm. It makes sense that you would see these kinds of effects in the reproductive tract, but that it’s happening in the water is pretty amazing.”

Story Source:

The above post is reprinted from materials provided by University of California – Santa Cruz. The original item was written by Tim Stephens. Note: Content may be edited for style and length.

{Human babies born via cesarean section miss out on an opportunity to pick up beneficial microbes that other babies get when they take a trip through mom’s vagina. And even though the scientific jury’s still out on whether this is a good idea, some parents have been wiping their C-section babies down with vaginal fluid in the hopes that their newborns might get some of those microbial benefits, Laura Sanders reported earlier this yearover at the Growth Curve blog.}

Microbial transfer from mom to offspring happens in a lot of species, but researchers are more familiar with how species that give live birth do this than those that lay eggs, biologist Stacey Weiss of the University of Puget Sound in Tacoma, Wash., noted August 1 at the 53rd Annual Conference of the Animal Behavior Society. Researchers have found that moms can transfer microbes right into the egg itself before it is laid or onto or near the egg after laying.

But Weiss thinks that such microbial transfer might happen through another route — as eggs travel through a female animal’s cloaca. (The cloaca is a combination of genital tract and end of the digestive system found in many invertebrates and most vertebrates, except most mammals.) She and her colleagues have been studying whether striped plateau lizard moms transfer microbes that protect their eggs from pathogens.

“Pathogenic infection is one of the leading causes of egg mortality,” she said. And some studies have proposed that microbes might be able to protect against those infections. None have yet proposed that the source of the microbes could be the cloaca, but this might be a common source since “all vertebrate eggs go through cloacas, and all cloacas have microbes,” she said.

Weiss latched onto the idea that microbes from the cloaca might be important after noticing that when she obtained eggs through dissection, they tended to have a lower survival rate than eggs that were laid. The dissected eggs often succumbed to fungal infections, while the laid eggs did not.

She and her team started by comparing the microbiomes of male and female lizards’ cloacas. “Females are different than males,” she said. Males had more diverse microbial communities in their cloacas. Females were missing whole categories of microbes found in males and had one type that is known to have antifungal activity.

The researchers then compared the microbiomes of eggs that were laid with those that had been dissected out. The team is still waiting on the results of DNA tests that will tell them exactly what kinds of microbes are found on the eggs, but initial results showed that the laid eggs are more likely to have any bacteria at all. “There’s something about going through the cloaca that is increasing bacterial load on these eggshells,” Weiss said. Fungi, though, showed up only on eggs that had been obtained through dissection.

Weiss, her colleagues and some high school students then performed tests in which fungus was applied directly to eggs. They found that laid eggs were able to inhibit fungal growth while dissected eggs were not. So it appears that the mom’s cloaca microbiome may indeed be providing some protection for her offspring.

Weiss said that these results, while still preliminary, may help expand what parental protection of offspring means. In species without direct parental care, transfer of microbes might be an important way that moms and dads help to keep their offspring safe.

{Lions in West and Central Africa form a unique group, only distantly related to lions in East and Southern Africa, biologists have discovered.}

Lions in West and Central Africa form a unique group, only distantly related to lions in East and Southern Africa. Biologists at Leiden University confirm this in an article published in Scientific Reports.

{{Genetic data}}

In this study, the researchers gathered a genetic dataset of lion populations covering a total of 22 countries. This included samples from each remaining lion population in West and Central Africa, a region where lions and other wildlife are rapidly declining as a consequence of the increasing human population. The researchers managed to gather all the information by teaming up with other people in the field and local conservationists.

{{300,000 years ago}}

Based on the genetic data, it was estimated that the split between the two major groups that can be identified in the lion must have occurred 300,000 years ago. To explain what happened in their evolution, the researchers made a reconstruction of African climatological history. It seems that periodic expansions of the rain forest and the desert drove lions into isolated pockets of suitable habitat, where the different genetic lineages originated that can still be observed today.

{{Other mammals}}

This influenced not only the patterns we observe in the lion, but also in other large mammals such as giraffe, buffalo, hartebeest, cheetah and spotted hyena. A general pattern is emerging that shows that many large African savannah mammals show very similar arrangements, with unique lineages in West and Central Africa.

{{Reason for concern}}

The strong declines in wildlife populations in large parts of West and Central Africa are therefore a reason for major concern. The fact that this region seems to harbour a lot of unique genetic lineages makes conservation in the area extremely important. A delegation from Leiden University will participate in the IUCN World Conservation Congress in September 2016, and will lead a Side Event that aims to establish a Species Action Plan for West and Central Africa.The researchers hope that this will facilitate coordination and funding of projects in the region.

{Pinatubo eruption masked acceleration in satellite record.

Greenhouse gases are already having an accelerating effect on sea level rise, but the impact has so far been masked by the cataclysmic 1991 eruption of Mount Pinatubo in the Philippines, according to a new study.}

Greenhouse gases are already having an accelerating effect on sea level rise, but the impact has so far been masked by the cataclysmic 1991 eruption of Mount Pinatubo in the Philippines, according to a new study led by the National Center for Atmospheric Research (NCAR).

Satellite observations, which began in 1993, indicate that the rate of sea level rise has held fairly steady at about 3 millimeters per year. But the expected acceleration due to climate change is likely hidden in the satellite record because of a happenstance of timing: The record began soon after the Pinatubo eruption, which temporarily cooled the planet, causing sea levels to drop.

The new study finds that the lower starting point effectively distorts the calculation of sea level rise acceleration for the last couple of decades.

The study lends support to climate model projections, which show the rate of sea level rise escalating over time as the climate warms. The findings were published today in the open-access Nature journal Scientific Reports.

“When we used climate model runs designed to remove the effect of the Pinatubo eruption, we saw the rate of sea level rise accelerating in our simulations,” said NCAR scientist John Fasullo, who led the study. “Now that the impacts of Pinatubo have faded, this acceleration should become evident in the satellite measurements in the coming decade, barring another major volcanic eruption.”

Study co-author Steve Nerem, from the University of Colorado Boulder, added: “This study shows that large volcanic eruptions can significantly impact the satellite record of global average sea level change. So we must be careful to consider these effects when we look for the effects of climate change in the satellite-based sea level record.”

The findings have implications for the extent of sea level rise this century and may be useful to coastal communities planning for the future. In recent years, decision makers have debated whether these communities should make plans based on the steady rate of sea level rise measured in recent decades or based on the accelerated rate expected in the future by climate scientists.

The study was funded by NASA, the U.S. Department of Energy, and the National Science Foundation, which is NCAR’s sponsor.

{{Reconstructing a pre-Pinatubo world}}

Climate change triggers sea level rise in a couple of ways: by warming the ocean, which causes the water to expand, and by melting glaciers and ice sheets, which drain into the ocean and increase its volume. In recent decades, the pace of warming and melting has accelerated, and scientists have expected to see a corresponding increase in the rate of sea level rise. But analysis of the relatively short satellite record has not borne that out.

To investigate, Fasullo, Nerem, and Benjamin Hamlington of Old Dominion University worked to pin down how quickly sea levels were rising in the decades before the satellite record began.

Prior to the launch of the international TOPEX/Poseidon satellite mission in late 1992, sea level was mainly measured using tide gauges. While records from some gauges stretch back to the 18th century, variations in measurement technique and location mean that the pre-satellite record is best used to get a ballpark estimate of global mean sea level.

To complement the historic record, the research team used a dataset produced by running the NCAR-based Community Earth System Model 40 times with slightly different — but historically plausible — starting conditions. The resulting simulations characterize the range of natural variability in the factors that affect sea levels. The model was run on the Yellowstone system at the NCAR-Wyoming Supercomputing Center.

A separate set of model runs that omitted volcanic aerosols — particles spewed into the atmosphere by an eruption — was also assessed. By comparing the two sets of runs, the scientists were able to pick out a signal (in this case, the impact of Mount Pinatubo’s eruption) from the noise (natural variations in ocean temperature and other factors that affect sea level).

“You can’t do it with one or two model runs — or even three or four,” Fasullo said. “There’s just too much accompanying climate noise to understand precisely what the effect of Pinatubo was. We could not have done it without large numbers of runs.”

{{Using models to understand observations}}

Analyzing the simulations, the research team found that Pinatubo’s eruption caused the oceans to cool and sea levels to drop by about 6 millimeters immediately before TOPEX/Poseidon began recording observations.

As the sunlight-blocking aerosols from Mount Pinatubo dissipated in the simulations, sea levels began to slowly rebound to pre-eruption levels. This rebound swamped the acceleration caused by the warming climate and made the rate of sea level rise higher in the mid- to late 1990s than it would otherwise have been.

This higher-than-normal rate of sea level rise in the early part of the satellite record makes it appear that the rate of sea level rise has not accelerated over time and may actually have decreased somewhat. In fact, according to the study, if the Pinatubo eruption had not occurred — leaving sea level at a higher starting point in the early 1990s — the satellite record would have shown a clear acceleration.

“The satellite record is unable to account for everything that happened before the first satellite was launched, ” Fasullo said. “This study is a great example of how computer models can give us the historical context that’s needed to understand some of what we’re seeing in the satellite record.”

Understanding whether the rate of sea level rise is accelerating or remaining constant is important because it drastically changes what sea levels might look like in 20, 50, or 100 years.

“These scientists have disentangled the major role played by the 1991 volcanic eruption of Mt. Pinatubo on trends in global mean sea level,” said Anjuli Bamzai, program director in the National Science Foundation’s Division of Atmospheric and Geospace Sciences, which funded the research. “This research is vital as society prepares for the potential effects of climate change.”

Because the study’s findings suggest that acceleration due to climate change is already under way, the acceleration should become evident in the satellite record in the coming decade, Fasullo said.

Since the original TOPEX/Poseidon mission, other satellites have been launched — Jason-1 in 2001 and Jason-2 in 2008 — to continue tracking sea levels. The most recent satellite, Jason-3, launched on Jan. 17 of this year.

“Sea level rise is potentially one of the most damaging impacts of climate change, so it’s critical that we understand how quickly it will rise in the future,” Fasullo said. “Measurements from Jason-3 will help us evaluate what we’ve learned in this study and help us better plan for the future.”

{New fossil finds from China push back the origins of deep soils by 20 million years, new research has uncovered. This is a key part of the stepwise conquest of the land and transformation of the continents, researchers have discovered.}

New fossil finds from China push back the origins of deep soils by 20 million years, new research has uncovered.

This is a key part of the stepwise conquest of the land and transformation of the continents, researchers from the universities of Peking and Bristol have discovered.

One of the greatest transitions in Earth history was the greening of the land. Up to 450 million years ago, there was no life outside water, and the land surface was a rocky landscape. Without plants there were no soils, and the rocky landscape eroded fast. Then the first tiny plants crept out of the water, and provided a green fringe. However, they could not venture far from the edge of the water.

By 390 million years ago, in the Middle Devonian, the first trees emerged. These early trees were only a few metres tall, but they could survive in soils away from the edges of rivers and streams. Importantly, they sent roots deep into the rocks, and helped develop thick soils, and the landscapes began to stabilize.

The new Chinese find, published in Proceedings of the National Academy of Sciences, is of deep rooting systems in Early Devonian rocks, from Yunnan in South China.

The study leader, Jinzhuang Xue from Peking University in Beijing, said: “We have been doing fieldwork in the Devonian rocks of Yunnan for some time, and we kept finding large-scale structures up to 1 metre deep in the red rocks. They looked like a plant called Drepanophycus, already known from rocks of the same age in Europe and North America.”

The roots are typically 1 cm in diameter, and they branch continuously. They are tightly packed, with as many as 1000 roots in every square metre of sediment examined.

“These roots are found in deep soils, and in fact the two go hand in hand,” said Mike Benton of the University of Bristol, one of the co-authors. “Soils are made by plants and animals, and they have a great stabilizing effect, taking up rainwater like a sponge and limiting erosion rates. From this time onwards, river systems changed their type, from fast-flowing, to slower-moving, meandering streams.”

Measurements of the soil thickness and comparisons with modern floodplain soils suggest it may have taken 50-200 years for one soil bed to form, and nodules in the Chinese Devonian soils suggest that the stack of soils may represent a span of 10,000-200,000 years, a long time for landscape stability.

{Rwanda Wildlife Conservation Association in collaboration with Rwanda Development Board (RDB) is set to relocate 21 cranes from the residence of former president of Rwanda, Habyarimana Juvenal to Akagera National Park.}

Dr Olivier Nsengimana who is in charge of protection of cranes’ lives in Rwanda has told IGIHE the museum accommodated 33 cranes but only 21 were found healthy to be easily integrated in wild life. This will be the third round of cranes transferred to the park.

The cranes were collected from people’s residents who owned them as pets.

The program of transferring the birds was initiated in 2014 after realizing the dwindling numbers of cranes as people took them to their homes.

Dr Nsengimana says that they have already registered 216 cranes from people’s residences since 2014 while 300 cranes were counted in people’s homes in 2013.

Today 77 cranes have been taken to the park. Cranes that cannot adapt to wild life will be relocated to special constructed area.

Dr Olivier explained that cranes bring an added value to Rwanda’s birding. He urged people to register cranes in their homes.