Study shows temperature alters developing nervous system in frogs

by UC Davis, 5/23/19

The external growth of frogs from egg to larvae enable researchers to explore how genes and the environment interact, including the role that temperature-sensitive channels play in nervous system development and disease. Credit: UC Davis Health

Can the environment affect how the spinal cord develops specialized circuitry, or is that process hardwired, following prescribed genetic instructions turned on early in the embryo?

A UC Davis study that compared the effects of cold and warm temperatures on the development of frog eggs into larvae found that environmental temperature significantly changes how the nervous system develops.

The study, which appears online May 23 in the journal Current Biology, found environmental temperature activated temperature-sensitive channels, influencing gene expression and altering neurodevelopment. The research, while conducted in frogs, has parallels across species, including humans.

"We found that the temperature-sensitive channel TRPM8 drives changes in the developing nervous system, allowing frogs to adapt to the environment," said Laura Borodinsky, professor of physiology and membrane biology at UC Davis School of Medicine and study senior author.

"Larvae grown in cold temperatures had more neurons responsible for movement—a crucial function that better equips young frogs to escape predators and other potential dangers," she said. "They also had larger muscle mass and a stronger swim response than those reared in warmer temperatures when tested at cold temperatures.”

Temperature important for neurodevelopment in humans

Temperature is an important factor in the development of the nervous system in humans. Newborns, especially premature babies, do not develop the ability to regulate body temperature until a few months after birth or even longer. Studies also suggest that fever during pregnancy may affect the developing brain and nervous system, increasing the risk of autism spectrum disorder and schizophrenia.

Borodinsky believes when temperature changes are sudden and occur during critical periods of development—or when molecular mechanisms to adapt to these changes are not working—disruptions in nervous system development can affect health.

Temperature channels as a way the environment changes gene expression

Temperature-sensitive channels belong to a diverse family of ion channels, TRP channels, that respond to a range of conditions. While some TRP channels are temperature sensors, others are sensitive to pain, pH, touch, light and sound. These cellular pathways that allow organisms to sense temperature are well-conserved through evolution and present across species.

For the study, Kira A. Spencer, first author of the paper and a former graduate student in the Neuroscience Graduate program at UC Davis, raised fertilized frog eggs at cold or warm temperatures in Petri dishes. At the larval stage, they measured responses to light touch and swimming responses, and number of spinal motor neurons. They assessed the dependence of spontaneous electrical activity, which drives many aspects of neuronal differentiation, on temperature, as well as the genetic factors that regulate developing spinal cord cells and the role of the cold-temperature channel TRPM8.

"We found that the cold-temperature sensitive channel TRPM8 mediates the developmental changes that give frog larvae an advantage and allow them to function optimally in cold temperatures," Spencer said.

"Our results provide insight into how the environment influences gene expression during development, and point to a promising avenue for exploring how genes and the environment interact, including the role that other TRP channels play in nervous system development and disease."

How male dragonflies adapt wing color to temperature

January 23, 2019, Case Western Reserve University

New research from Case Western Reserve University in how dragonflies may adapt their wing color to temperature differences might explain color variation in other animals, from lions to birds.

Further, the findings could also provide evolutionary biologists clues about whether rising global temperatures might adversely affect some species.

Michael Moore, a graduate biology student, and Ryan Martin, an assistant professor of biology, recently published their findings in the journal Ecology Letters.

"People have long been aware of variation in dragonfly wing color, but what we are showing in this new work is an overlooked environmental factor—how temperature affects coloration," Martin said. "This could turn out to also determine some of the really cool extravagant traits we like to look at, such as coloration in birds."

Their findings follow a two-year study that began with a hunch about how the wing color on male Blue Dasher dragonflies in the western United States was different from their counterparts in Northeast Ohio.

They reviewed vast amounts of dragonfly photographs compiled by citizen scientists on the website iNaturalist.org and then, with the help of graduate student Iulian Gherghel, cross-referenced that information with weather data.

Read more at: 

Temperature helps drive the emergence of different personalities in spiders

July 21, 2016

Like people, animals have personalities. And their personalities differ, sometimes hugely, on traits like shyness and aggressiveness. Among the big questions are where those differences come from, why they exist, and how they are maintained. Now researchers from the University of North Carolina at Chapel Hill have uncovered an unexpected benefit of these personalities: to protect societies from extreme temperature changes.

The work, led in part by Spencer Ingley, a postdoctoral fellow at UNC College of Arts and Sciences, is particularly relevant at a time when the planet's climate is projected to increase on the order of 3 to 12 degrees Fahrenheit by 2100. It could also have far reaching implications on how to restore animals in their different habitats in an increasingly changing world.

"We live in a time of global change," said Ingley. "Scientists are seeing that these changes can have a huge impact on individual organisms and groups of organisms. But people have rarely looked at personalities and how the personalities of groups can alter their response to these changes, particularly in different temperature environments."

This work focused on the tangle web spider, known to scientists as Anelosimus studiosus, which lives in North Carolina and across North and South America. In this species, individual spiders have either one of two personalities: docile or highly aggressive. Together, they not only share the same living space but also share in the duties of brood care and capturing of prey.

Ingley and his team, which included researchers from Israel, Australia, and the U.S., looked at the effect of temperature - 75 to 93 degrees Fahrenheit - on the spiders' ability to survive and reproduce as an individual and within a colony. They found that aggressive spiders were less likely to survive and reproduce at higher temperatures. But the opposite was true for docile spiders: as the temperature heated up, the better they reproduced and survived. The researchers saw the same pattern when the colonies were made up of all aggressive individuals or all docile ones.

But when a colony had different personalities - a mix of aggressive and docile spiders - the aggressive spiders didn't die in hot temperatures and docile ones didn't die in cooler ones.

Continued ...

The Iguana in the Bathtub - via Herp Digest

NOV. 26, 2014, NYtimes Magazine

By ANNE DOTEN

When the temperature dipped below 40, iguanas started falling from the trees. Small, sleek green iguanas; big iguanas as long as four feet from snout to tail, scales cresting gloriously from their heads; orange-and-green iguanas, their muscled, goose-pimpled arms resolving into sharp claws. Iguanas were everywhere: in the bushy areas surrounding canals, on sidewalks, in backyards, lying helpless among the fallen, rotting fruit of mango and orange trees.

The iguanas lay on the ground as if they were dead, a rhapsody of corpses dotting the landscape like musical notation. But they weren’t dead — not at first, anyway. They had lapsed into a sort of hibernation in response to the cold. If it warmed up fast enough, they would awaken from their deep slumbers and climb back onto their perches in trees or return to sunning themselves on rocks and the hot metal encasements of electrical boxes.

Cold snaps do sometimes occur in South Florida, but they usually pass within 48 hours. This time, the frigid temperatures lingered for days, and the iguanas remained motionless where they lay.

On the third day of the iguana plague, my husband, John, arrived home carrying a cardboard box. Inside was a large green iguana, slender and peaceful, lying on its back.

“What the hell?” I said.

“I think it’s still alive,” he said.

I followed him to the bathroom. He placed the box inside the tub and edged past me toward the hallway.

“Where are you going?”

He didn’t answer but returned a minute later wearing yellow rubber gloves and carrying a stethoscope in his hands, the cheap one he used when he was in nursing school. He perched on the edge of the bathtub, stuck the rubber buds in his ears and carefully lifted the iguana out of the box. Its limp, lean arms looked strangely graceful. Balancing its body with one hand, John placed the flat circular end of the stethoscope against the reptile’s chest.

“I should get my camera,” I said. “Do you know how crazy this looks?”

“I’m checking for a heartbeat,” he said.

I was quiet for a few moments, then said: “Well? Did you find one?”

“Shh.” John stared at a space on the green tiled wall, face crimped in concentration. Then he frowned. “Maybe the stethoscope isn’t strong enough. Iguanas have really thick skin.”

“How about some chest compressions? Maybe a little mouth to mouth?”

He gave me a withering look as he gently returned the iguana to its cardboard cradle. He pulled the stethoscope out of his ears.

“Can you get a towel?” he said. “I want to keep him warm.”

why not run hot water over it? it needed to really warm up.also - why did you drop it in the dumpster? you could have at least buried it....

Iguanas are invasive, usually dumped as former pets, and are not great for Florida. Thankfully, there's one less to breed.

Well, all the love? was it sincere and compassion, was shown, but the two of them dumped the Iguana in a dumpster? I question their concern?...

I went to the closet and chose an old green towel that was badly pilled and fraying at the edges. I handed it to John.

“Let’s just wait until the morning,” he said. “Maybe he’ll come out of it.”

I peered down at the iguana. It did look as if it was sleeping. Maybe John was right. Maybe it was still alive, and it just took a while to thaw out of its hibernation. Its hands looked almost human, only they were green and slender and elongated, with sharp talons on the ends. I fought the insane impulse to reach out and grab its fingers, imagining it would squeeze back, like a newborn infant.

John laid the towel over the iguana, as if tucking it into bed.

We rose early the next morning. John put his ear to the closed bathroom door to listen for movement. Hearing nothing, he slowly opened it. I flinched, picturing the iguana lunging toward us, claws bared, ready to shred our skin like Cheddar. But nothing stirred. Together we tiptoed toward the tub and peered inside the box. The iguana was still immobile, and its skin was pale, almost gray instead of green. The thing was dead. It was definitely dead.

John bent down and lifted the iguana’s cardboard coffin. Still in my pajamas, I slipped on a pair of shoes and opened the front door. Our funeral procession to the Dumpster was short and somber. I held the lid open, and John dropped in the box. The thud reverberated inside the steel tomb.

We stared at the Dumpster for a few moments. “I thought I could save it,” John said.

Regret etched lines around his eyes. I grabbed his hand and squeezed.

“Sugar,” I said, using our pet name for each other. “Some things are just beyond saving.”

How honey bees stay cool

Honey bees, especially the young, are highly sensitive to temperature and to protect developing bees, adults work together to maintain temperatures within a narrow range. Recently published research led by Philip T. Starks, a biologist at Tufts University's School of Arts and Sciences, is the first to show that worker bees dissipate excess heat within a hive in process similar to how humans and other mammals cool themselves through their blood vessels and skin.

"This study shows how workers effectively dissipate the heat absorbed via heat-shielding, a mechanism used to thwart localized heat stressors," says Starks. The research is published in the June 10 edition of the journal Naturwissenschaften, which appeared online April 24.

This discovery also supports the theoretical construct of the bee hive as a superorganism—an entity in which its many members carry out specialized and vital functions to keep the whole functioning as a unit.

Read more at: 

Dispersal 'key to reptile survival'

By Zoe GoughReporter, BBC Nature

Reptiles whose gender depends on temperature must become more widespread to survive the effects of climate change, according to new research.

Temperature of egg incubation decides gender in some reptile species, such as alligators and some turtles.

Australian researchers found that in populations where more females are produced, male dispersal is vital.

Species unable to disperse could become extinct from some areas, suggested the research reported in BMC Ecology.

Alligators, some turtles, and the tuatara - found only in New Zealand - all produce offspring whose gender is determined by temperature.

These species are considered to be especially vulnerable to climate warming, because at higher temperatures they produce only one sex.

Previous studies have suggested that the best way for reptiles to respond is to alter the temperature of their nest by seeking shaded areas, digging deeper nests and nesting earlier in the season.

Read more

British butterfly desperate for warm weather this summer

Butterflies are extremely sensitive to changes in temperature and new research has revealed that when summer weather turns bad the Silver-spotted skipper battles for survival.

June 2013. A 27 year study by researchers at the University of Exeter and others estimated changes in temperature across a range of silver-spotted skipper habitats and found that localised fluctuations in temperature lead to extreme fluctuations in the butterfly population size and in the probability of the butterflies colonising new sites. The butterfly, which previously faced extinction from habitat loss, is recovering following conservation efforts but the recent cool wet summers in England have almost stalled its progress.

Lead author Dr Jonathan Bennie from the Environment and Sustainability Institute at the University of Exeter said: "Although we know that the climate overall is warming there is still much variability in the weather from one year to the next. This variability presents a threat to southern British butterflies that we might expect to take advantage of warmer conditions to colonise further north. In warmer years the silver-spotted skipper, which needs a balmy 25°C to become fully active, has expanded its range. However during the recent cold wet summers we have found the skipper clinging to the warmest south-facing hillsides waiting for better weather."

Continued

Ants Rise With Temperature

Mar. 21, 2013 — Warm nights might be more important than hot days in determining how species respond to climate change. "Rising minimum temperatures may be the best way to predict how climate change will affect an ecosystem," said Robert Warren, assistant professor of biology at SUNY Buffalo State. "Cold extremes that once limited warm-adapted species will disappear in a warming global climate."

Global Change Biology published a study conducted by Warren with Ph.D. candidate Lacy Chick of the University of Tennessee-Knoxville. The study shows that the lowest- -- not the highest--temperatures are critical in determining the migration of warmth-loving ants, Aphaenogaster rudis, to higher elevations.

As they migrate, A. rudis--a reddish ant with light-colored legs -- displace Aphaenogaster picea, a dark ant with dark legs. A. picea thrive at temperatures about 2ºC colder than A. rudis can tolerate. Aphaenogaster ants are the dominant woodland seed dispersers in eastern forests. "So it's possible that the displacement of A. picea may affect the spread of seeds produced by early spring ephemerals," said Warren.

By comparing data collected in 1974 to current data, Warren and his team were able to compare the percentage of A. rudis and A. picea at different elevations in the Southern Appalachian Mountains in Georgia. In 1974, A. rudis accounted for less than 60 percent of the two species at 500 meters and less than 20 percent at 700 meters. At 900 meters (nearly 3,000 feet), A. rudis were almost nonexistent.

Continued:  http://www.sciencedaily.com/releases/2013/03/130321081505.htm

Cities Affect Temperatures for Thousands of Miles – via Herp Digest

Jan. 27, 2013 — Even if you live more than 1,000 miles from the nearest large city, it could be affecting your weather.

In a new study that shows the extent to which human activities are influencing the atmosphere, scientists have concluded that the heat generated by everyday activities in metropolitan areas alters the character of the jet stream and other major atmospheric systems. This affects temperatures across thousands of miles, significantly warming some areas and cooling others, according to the study this week in Nature Climate Change.

The extra "waste heat" generated from buildings, cars, and other sources in major Northern Hemisphere urban areas causes winter warming across large areas of northern North America and northern Asia. Temperatures in some remote areas increase by as much as 1 degree Celsius (1.8 degrees Fahrenheit), according to the research by scientists at the Scripps Institution of Oceanography; University of California, San Diego; Florida State University; and the National Center for Atmospheric Research.

At the same time, the changes to atmospheric circulation caused by the waste heat cool areas of Europe by as much as 1 degree C (1.8 degrees F), with much of the temperature decrease occurring in the fall.

The net effect on global mean temperatures is nearly negligible -- an average increase worldwide of just 0.01 degrees C (about 0.02 degrees F). This is because the total human-produced waste heat is only about 0.3 percent of the heat transported across higher latitudes by atmospheric and oceanic circulations.

However, the noticeable impact on regional temperatures may explain why some regions are experiencing more winter warming than projected by climate computer models, the researchers conclude. They suggest that models be adjusted to take the influence of waste heat into account.

"The burning of fossil fuel not only emits greenhouse gases but also directly affects temperatures because of heat that escapes from sources like buildings and cars," says NCAR scientist Aixue Hu, a co-author of the study. "Although much of this waste heat is concentrated in large cities, it can change atmospheric patterns in a way that raises or lowers temperatures across considerable distances."

Distinct from urban heat island effect

The researchers stressed that the effect of waste heat is distinct from the so-called urban heat island effect. Such islands are mainly a function of the heat collected and re-radiated by pavement, buildings, and other urban features, whereas the new study examines the heat produced directly through transportation, heating and cooling units, and other activities.

The study, "Energy consumption and the unexplained winter warming over northern Asia and North America," appeared online January 27. It was funded by the National Science Foundation, NCAR's sponsor, as well as the Department of Energy and the National Oceanic and Atmospheric Administration.

Hu, along with lead author Guang Zhang of Scripps and Ming Cai of Florida State University, analyzed the energy consumption -- from heating buildings to powering vehicles -- that generates waste heat release. The world's total energy consumption in 2006 was equivalent to a constant-use rate of 16 terawatts (1 terawatt, or TW, equals 1 trillion watts). Of that, an average rate of 6.7 TW was consumed in 86 metropolitan areas in the Northern Hemisphere.

Using a computer model of the atmosphere, the authors found that the influence of this waste heat can widen the jet stream.

"What we found is that energy use from multiple urban areas collectively can warm the atmosphere remotely, thousands of miles away from the energy consumption regions," Zhang says. "This is accomplished through atmospheric circulation change."

The release of waste heat is different from energy that is naturally distributed in the atmosphere, the researchers noted. The largest source of heat, solar energy, warms Earth's surface and atmospheric circulations redistribute that energy from one region to another. Human energy consumption distributes energy that had lain dormant and sequestered for millions of years, mostly in the form of oil or coal.

Though the amount of human-generated energy is a small portion of that transported by nature, it is highly concentrated in urban areas. In the Northern Hemisphere, many of those urban areas lie directly under major atmospheric troughs and jet streams.

"The world's most populated and energy-intensive metropolitan areas are along the east and west coasts of the North American and Eurasian continents, underneath the most prominent atmospheric circulation troughs and ridges," Cai says. "The release of this concentrated waste energy causes the noticeable interruption to the normal atmospheric circulation systems above, leading to remote surface temperature changes far away from the regions where waste heat is generated."

Tree Cricket's Song in Tune with the Temperature

Among many male crickets, larger body size means a lower pitched song and more attention from the lady crickets. But male tree crickets break this rule: The pitch of their song changes with temperature. 

The basic mechanics are straightforward, according to new research that explores tree crickets' unusual song. Tree crickets have more elongated wings than other species, particularly field crickets, and tree crickets vibrate their entire wing when they call, rather than just part of it, as other crickets do.

But the discovery points to another, trickier question: Why?

The variability in male tree crickets' call creates a problem. Normally, female crickets find their mates by tuning into the precise frequency at which the males broadcast their chirpy song, tuning out other noise. But if males' calls aren't finely tuned, how do females home in on them?

Continued:  http://www.livescience.com/19992-tree-cricket-mating-calls.html