Archive for April, 2016

Bee learning ability slowed by pesticides, study finds

April 28, 2016 Leave a comment
Bumble bee - courtesy Wikimedia

This image shows a bumble bee loaded with pollen. Image courtesy Wikimedia.

Bees exposed to pesticides might have a harder time learning how to pollinate flowers than those who are not exposed to the substances, a new study suggests.

The paper, which was published in the March 14 edition of Functional Ecology, is the first to show that neonicotinoids, a class of pesticides that is now commonly used to protect a variety of agricultural crops, may impact the ability of individual bees to forage for nectars and pollen. It examined the impact of a compound called thiamethoxam on bumblebees.

“What we found is that bees exposed to pesticide initially collected more pollen, but it took them more visits to flowers to properly ‘learn’ this behavior,” Dr. Dara Anne Stanley, the lead author of the paper and a researcher at the University of KwaZulu-Natal in South Africa, said. “Control bees collected less pollen, but learned the behavior properly after visits to less flowers. Therefore control bees may be investing more time in learning this behavior properly.”

That result is consistent with the findings of other recent studies. For example, a paper published last year showed that bumblebees exposed to pesticides suffer memory loss. Another paper published in 2015 demonstrated that bumblebee colonies that encounter neonicotinoids tend to forage for pollen less than those colonies that do not come into contact with the compounds.

Neonicotinoids appear to target the area of a bee’s brain that governs the insect’s behavior.

“Neonicotinoid pesticides in particular target a region of the insect brain called the nicotinic acetylcholinase receptors (nAChRs) where they target cholinergic signaling by inhibiting acetylcholinesterase,” Stanley said in an e-mail message. “As the nAChRs have been associated with behavior in insects, in particular learning and memory, this means these pesticides at sub-lethal doses have the potential to cause changes in insect behavior.”

The term cholinergic signaling refers to the movement of neurotransmitters in an organism’s nervous system. Those compounds carry information across synapses.

If the pesticide is used near a bee colony, then its impacts on the ability of individual bees to obtain pollen could negatively affect the whole colony.

“As bees in particular display a range of sophisticated behaviors involved in navigation, foraging etc, these pesticides have the potential to effect foraging success and ultimately colony health,” Stanley said.

That may be less of a worry for honeybees, which live in large colonies. Stanley explained that a recent study conducted in Sweden indicated that honeybees are affected by exposure to pesticide-treated crops less rapidly than bumble bees.

“Honeybee colonies are extremely large with thousands of workers, and therefore the effects of pesticides on individuals would have to be very strong to see any impacts on the whole colony, and if there are impacts it could take many years to become apparent,” she said. “However, bumblebee colonies are much smaller and therefore any impacts on individuals are likely to be much more influential on the colony as a whole. When it comes to solitary bees, each individual female builds her own nest, so they are likely to be even more susceptible to any behavioral effects on individuals.”

While sale of neonicotinoids are now worth about $2.6 billion per year to manufacturers, the substances are thought to be dangerous to many other organisms. A series of papers published in 2014 indicated that they “exhibit very high toxicity” to many invertebrates and that some bird and fish species are especially vulnerable to harm caused by the use of neonicotinoids.

305 million year-old ancestor of spiders is identified

April 28, 2016 Leave a comment
Early arachnid

Idmonarachne brasieri lived about 305 million years ago. Image courtesy University of Manchester.

Paleontologists have identified an ancestor of modern spiders that lived before the dinosaurs began their long domination of the planet.

The arachnid’s fossil remains were found during the mid-1970s in Europe embedded in an iron-rich mineral, siderite, that is difficult for x-rays to penetrate. Researchers used a synchotron, which emits more powerful x-rays, to identify the organism.

Named Idmonarachne brasieri, the organism was likely a member of a group of arachnids called uraraneids. These animals lacked spinarets, which modern spiders use to spin webs, and instead would have discharged silk in sheets.

“Our new fossil occupies a key position in the evolution of spiders,” Dr. Russell Garwood of the University of Manchester, the lead author of a paper documenting the discovery, said. “It isn’t a true spider, but has given us new information regarding the order in which the bits of the anatomy we associate with spiders appeared as the group evolved.”

Scientists know little of the origin of spiders and the evolutionary path by which such anatomical features as spinarets formed is not well understood.

The paper appears in the March 30 edition of Proceedings of the Royal Society B.


Fossils of largest-ever marine crocodile found in Africa

April 28, 2016 Leave a comment

Scientists have found evidence that a ocean-dwelling crocodile about 10 meters long once roamed the area we now know as north Africa.

The beast, which also likely weighed at least three tons, lived about 120-130 million years ago.

Dubbed Machimosaurus rex, the crocodile is the largest known of its kind. A marine reptile, it thrived at a time in Earth’s geologic history when the land now known as north Africa was submerged under an ocean.


Machimosaurus rex was a marine reptile, about 12 meters long, that swam in Cretaceous oceans. Illustration courtesy University of Alberta, illustration (c) Davide Bonadonna. All rights reserved.

Researchers discovered the species in 2014 when a skull measuring almost two meters in length was unearthed in Tunisia. The specimen has teeth that are are shaped like bullets, which the creature may have used to crush the carapaces of marine turtles.

The length of the animal is an estimate, based on the dimensions of similar organisms within the animal’s genus that lived during the Jurassic and Cretaceous periods.

“We have been digging in that area since 2011 because the rocks there are nothing like other places,” Federico Fanti, a paleontologist at the University of Bologna in Italy and lead author of the paper documenting the find, said in a statement. “Globally, good fossils are rare from this age—130 million years ago.”

Fanti and his team later found more of the specimen, including vertebrae, but were not able to remove those parts of the fossil because of ongoing unrest in the country.

The species is part of a larger genus that was first discovered in the nineteenth century. Among M. rex‘s close relatives are crocodilians that roamed Jurassic and Cretaceous period seas that then covered the part of Earth now known as Europe.

M. rex was the largest of the teleosaurids (marine crocodiles) in its genus.

While large, the croc is not the largest known from the planet’s long history of life. At least several species of freshwater crocodile that lived during the time of the dinosaurs, Sarcosuchus imperator and those in the genus Deinosuchus, were more imposing than M. rex.

S. imperator was about two meters longer than M. rex, while some Deinosuchus species may have been only slightly longer than M. rex.

The paper documenting the discovery of M. rex was published online in the Jan. 10, 2016 edition of Cretaceous Research.





Earth experiences 11th straight month of record warmth

April 28, 2016 Leave a comment

This graphic shows how much air temperatures all over Earth departed from the historic average during March 2016. Graphic courtesy NOAA National Centers for Environmental Information.

Humanity’s ongoing alteration of Earth’s atmosphere has now caused eleven straight months of record heat.

The National Oceanic & Atmospheric Administration announced April 19 that March continued the streak with an average worldwide temperature that was 2.2 degrees Fahrenheit above the twentieth century average for the month.

The month cemented the place of 2016’s first quarter as the warmest three-month period, relative to the norm, in recorded history.

“The departures are what we would consider astronomical,” NOAA climate scientist Jessica Blunden told the Associated Press. “It’s on land. It’s in the oceans. It’s in the upper atmosphere. It’s in the lower atmosphere. The Arctic had record low sea ice.”

“Everything everywhere is a record this month, except Antarctica,” Blunden continued in her AP interview. “It’s insane.”

March 2016 exceeded the previous record departure from the March mean for the period 1880-2016 by 0.54 degrees Fahrenheit.

The heat was particularly evident over land, where air temperatures last month were 4.19 degrees Fahrenheit above the twentieth century mean.

The agency also said that the average temperature above both land and sea surfaces across the globe during the first three months of this year was 2.07 degrees Fahrenheit higher than the twentieth century average. That is another record, exceeding the previous record set last year by 0.5 degrees Fahrenheit.

In the United States record heat was experienced in nearly every part of the country.

Deke Arndt, the leader of the climate monitoring branch at NOAA’s National Centers for Environmental Information, wrote in an April 12 blog post that every one of the nation’s climate divisions – sections distinguished by long-term climate patterns – was “warmer than normal” last month.

“The nationwide warmth was the result of unusual, and in some cases, record warmth, generally moving west to east across the CONUS,” Arndt wrote.

The acronym CONUS refers to the continental United States.

Divisional Average Temperature Ranks, March 2016 - courtesy NCEI

This graphic shows the departure from average monthly temperatures during March 2016 for climate divisions in the United States. Graphic courtesy NOAA National Centers for Environmental Information.

Up in the Arctic, the seasonal ice cover continued to shrink in March.

NASA Blue Marble image - March 24 Arctic sea ice cover

This NASA Blue Marble image shows Arctic sea ice extent on March 24, 2016, which averaged 14.52 million square kilometers (5.607 million square miles) on March 24, beating last year’s record low of 14.54 million square kilometers (5.612 million square miles) on February 25. Graphic courtesy National Snow and Ice Data Center/NASA Earth Observatory.

The average amount of territory in the Arctic that was covered by ice during the month was 7.02 percent below the 1981-2010 average and was the second-smallest ice cover during March since record-keeping began in 1979.

Arctic sea ice reached its maximum extent on March 24. Covering 14.52 million square kilometers (5.61 million square miles), it was the smallest maximum on record and was 1.12 million square kilometers (431,000 square miles) below average.

“I’ve never seen such a warm, crazy winter in the Arctic,” Dr. Mark Serreze, director of the National Snow and Ice Data Center in Boulder, Colo. and a professor of geography at the University of Colorado, said. “The heat was relentless.”

Serreze explained that, while the powerful El Nino that occurred this past winter may have helped drive down Arctic ice cover by causing circulation of warm air currents, the overall trend downward cannot be attributed to ENSO events.

“The system has always been variable,” he said. “It’s not like we’re going to set a new record each year. That’s not how the system works. If we recovered in the next year or two that would not be a surprise at all, but it would only be a temporary recovery.”

The average air temperature in the Arctic between Dec. 1 – Feb. 28 was 4-11 degrees Fahrenheit above average for that time period, according to an NSIDC press release.




SpaceX lands rocket at sea for first time

April 9, 2016 Leave a comment

A private company succeeded Friday in landing a rocket upright at sea for the first time in history.

SpaceX, which handles cargo launches for the International Space Station, said on its Twitter feed that the first stage of a Falcon 9 rocket that had lifted the Dragon cargo capsule to orbit had landed on a floating barge.

The company posted a video of the landing on its Twitter feed.

President Obama congratulated SpaceX in a message posted to his official Twitter feed, as did NASA.

NASA Image of the Day: Turbulent ocean

April 5, 2016 Leave a comment

NASA’s Image of the Day for April 5, 2016 shows the waters of the north Atlantic Ocean:

Atlantic Ocean, April 5, 2016

The Gulf Stream waters flow in somewhat parallel layers, slicing across what is otherwise a fairly turbulent western North Atlantic Ocean in this March 9, 2016 image collected by the Visible Infrared Imaging Radiometer Suite on NASA-NOAA’s Suomi NPP satellite. The turbulence is made visible by the pigmented phytoplankton it entrains. Photo courtesy NASA.

Some interesting things to see in the night sky during April

April 4, 2016 Leave a comment

Video courtesy NASA

This month provides an opportunity to see a meteor shower and three planets in the night sky.

The highlight will continue to be the chance to see Jupiter, which will shine brightly after being at opposition on March 8. Look to the south-southeast in the early evening, just after twilight; the solar system’s largest planet is in the constellation Leo. On April 17 you can see it moving with the waxing gibbous moon.

Mercury will become visible on April 8 as a fairly bright object with a -1 magnitude. The closest planet to the Sun passed its perihelion on April 5 and can be seen low in the western sky about 30 or 40 minutes after sunset. By April 18 Mercury will become quite a bit less bright, though it will be about 20 degrees east of the Sun by then. That makes it easier to see because it will be higher in the sky and will take longer to set. Whenever you observe the meteor shower, try to find a location away from any artificial lights.

You can best see Mars on or about April 24, when it reaches a magnitude of about -1.2 to -1.4. It will appear below the waxing gibbous moon as a yellowish-orange object. Look to the constellation Opheuchus to find Mars.

The Lyrid meteor shower peaks before dawn on April 22, but its annual visit corresponds with a full moon. However, the meteor shower starts on April 16, which might allow for some visibility of objects falling through the atmosphere before the full moon arrives.



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