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Jitterbug Like an Aphid

Wednesday, February 13th, 2013

(Video: Woolly aphids dancing on a beech tree at the Smithsonian Environmental Research Center. Credit: Tyler Bell/SERC)

Any creature with the word “blight” in its name can hardly escape being labeled a pest. Beech blight aphids are no exception. Like mosquitoes of the tree world, aphids have a vampirical tendency to suck the sap out of trees they colonize, and–while they do not usually kill the entire tree–they can take out some of its smaller branches.

But like all names, pest is a matter of perspective. And aphids have evolved some redeeming qualities as well. Not least is their peculiar ability to dance in the face of danger.

This quirk has earned them a more endearing nickname: the boogie-woogie aphid. Whenever aphids feel threatened, they raise their rear ends and sway, sometimes hundreds or thousands at a time. Up close their abdomens resemble white feather dusters. It’s a defensive dance meant to ward off predators. But in a flip of the natural order, it’s generally the children–not the adults–who do the defending. If larger creatures like moth larvae get too close, young aphid nymphs spin around and sting the predators with the same stylet mouth pieces they use to drain the beech branches.

And while aphids mean death for small tree branches, for other creatures they give life. After drinking the tree’s sap, aphids excrete it as sweet-smelling honeydew. Ants and other insects flock to it for the nutritious sugar. So do fungi, which rapidly colonize the honeydew and turn it into black sooty mold. Unlike the aphids, the fungi do not penetrate the tree’s surface. Some researchers doubt whether beech blight aphids have any serious effect on the tree’s health, other than producing “vast amounts of aesthetically displeasing sooty mold.” Which would make the name beech blight aphid, though technically accurate, a bit unjust.

As one reader pointed out, “woolly aphid” and “beech blight aphid” do not mean the same thing. “Beech blight aphid” refers to the species Grylloprociphilus imbricator. “Woolly aphid” is a broader name that includes beech blight aphids and other aphids that secrete waxy threads to resemble wool. The video above shows woolly aphids that are probably beech blight aphids.

Lost Turkey Abandoned in Nature Preserve

Friday, December 21st, 2012

by Kristen Minogue

A white pickup truck prepares to carry Tuck to a nearby farm. Tuck, a bronze heritage turkey, was discovered wandering alone on SERC property last week. His friendliness around people made staff suspect he was an abandoned pet. (Marvin Dorsey)

The following is a true story about how not to break up with a pet. Tuck (left) is a domestic turkey who found himself alone in the woods, presumably abandoned by his keeper and half-starved when SERC security discovered him last Thursday.

It’s not uncommon to hear about pets left on the sides of streets or in vacant houses when their owners, for one reason or another, decide they’re no longer able to keep them. These stories usually involve dogs, cats or the occasional boa constrictor. In their defense, some owners may believe their pets will be able to fend for themselves in the wild. The owner who dropped off Tuck may have been operating under a similar assumption. Unfortunately the assumption is almost always false.

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From the Field: Game Plan for Panama

Thursday, December 6th, 2012

by Kristy Hill, SERC marine invasions technician

Katrina Lohan packs rubber gloves, Ziploc bags and other field essentials for a science expedition. (Kristy Hill)

Katrina and I leave for Panama City in next week, so we’re gathering supplies and mapping out our game plan. We’re stoked to get this project rolling—beautiful surroundings and mandatory snorkeling in the tropics won’t be such bad work!

The critters we’re looking for grow on coral reefs, mangrove roots, sponges, pilings, sea walls and rocks. Our goal is to collect at least 50 to 60 oysters of three or four different species from three sites along the Caribbean coast. At each site, we’ll take water quality measurements such as salinity, temperature and oxygen content. We’ll take additional notes about the oysters’ habitats, such as their distance from the shore, the depth of the water, their proximity to ports or marinas, etc. We want to obtain as much data (or information) as possible so we can better understand the environment where the oysters and their potential parasites live.

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From the Field: Hunting for Parasites

Wednesday, December 5th, 2012

by Katrina Lohan, Smithsonian Environmental Research Center and National Zoo postdoc

Many people cringe when they hear the word “parasite”—not Katrina Lohan and Kristy Hill. Combined, the two of us have spent 12 years conducting research on parasites that infect bivalves (oysters, clams, mussels, etc.), crustaceans (crabs, shrimps, lobsters, etc.), and songbirds. We are both passionate about studying marine parasites and want to better understand how parasitism impacts marine animals. For the next few months, we’ll be searching for these parasites in waters all along the east coast of North America, from Maryland to Panama.

Katrina Lohan (right) and Kristy Hill are preparing to scour the coasts of North America for marine parasites infecting oysters and other shellfish. (Kim Holzer/SERC)

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Climate Change Stimulates Growth of Invasive “Super Weed”

Thursday, November 8th, 2012

by Kristen Minogue

Tom Mozdzer explores a patch of invasive Phragmites in SERC's global change wetland.

Is it better to be a jack of all trades or a master of some? In the plant world, it’s possible to do both–and that could make a huge difference in deciding which plants dominate under climate change. This holds especially true for one: the invasive reed Phragmites australis. Its ability to alter its anatomy enables it to grow well in just about any environment, including one spiked with CO2 and nitrogen, SERC ecologists discovered in a study published Oct. 31.

Plants like this are called “jack-and-master” plants. Typically, the most competitive plants surpass their neighbors through one of two strategies. “Jack-of-all-trades” plants do moderately well under most scenarios. Their competitors will surpass them when conditions are good, but if the environment becomes stressful, the jack of all trades will grow better. “Master-of-some” plants do very well under only a few conditions, so if the environment shifts in their favor, they are certain to emerge victorious. But a few types—the jack-and-master plants—can use both tactics. And the invasive Phragmites is one of them.

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What the Plantation Owners Left Behind

Tuesday, October 16th, 2012

by Kristen Minogue

Homestead House, called Woodlawn by its first residents in the early 1700s. (SERC)

On the western shore of Chesapeake Bay, less than a mile from the Rhode River, there is an old red house on an abandoned farm. Once, in the 18th century, it belonged to a thriving plantation. The hilled rows of tobacco have vanished, along with the slaves and field hands who planted them. But the scars on the landscape remain. The surrounding earth carries traces of how each of its inhabitants have used it, or abused it.

The house’s first inhabitants in the early 1700s called it Woodlawn. Today it is known simply as the Homestead House. The building and its surrounding farmland now sit within the Smithsonian Environmental Research Center. Instead of slaves and field hands, teams of volunteers are overturning the soil in search of clues about its past.

Archaeologist Jim Gibb began the excavation at SERC earlier in August. His volunteers come for a single afternoon, or several weeks. He isn’t terribly picky about long-term commitments. Gibb welcomes anyone who can handle a shovel and is at least ten years old (and even that rule is flexible). Under his guidance, they are piecing together the story of one household’s legacy on the land.

The team made one of their biggest discoveries just a few weeks into the project, when they uncovered a brick foundation sprinkled with household artifacts. One possibility is that it was a storage shed. Another, that it was someone’s home.

“If someone was living in that in the early 19th century, and we know where the owners were living, then we do the math,” Gibb said. “They have to be labor. And at that point, probably slave labor.”

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Nightly Oxygen Drops Deadly
for Chesapeake Oysters

Tuesday, September 25th, 2012

by Kristen Minogue

Slide of an oyster completely infected with Dermo.

Oysters in Chesapeake Bay face more dangers than overfishing and habitat loss. Over the last few decades they’ve also had to contend with crippling disease outbreaks. And according to marine ecologist Denise Breitburg, the wild day-night fluctuations in Bay waters aren’t helping.

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Land Hurricanes: The Science Behind the Derecho

Tuesday, July 3rd, 2012

by Kristen Minogue

Derecho storm front over Nebraska in August 2007. (MONGO)

To say the tempests of June 29 took the U.S. by surprise would be an understatement. Near Annapolis, the storms jumped from a mild 10 miles per hour to 54 miles per hour in just five minutes. In other places 70- and 80-mile per hour winds tore through hulking trees and power lines. And yet the most violent part of the storm lasted less than half an hour.

“It all happened in a matter of minutes….I’ve never seen anything like it,” said ecologist Pat Neale, who tracked the wind speeds on SERC’s meteorological tower.

How could something so quick cause so much damage? And how would a storm like that form in the first place?

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The Hidden Eyes of Blind Cats

Monday, April 9th, 2012

by Samantha Reed

Photo courtesy of Samantha Reed

Cats don’t need their eyes to see in the dark. It turns out they have something even better. This spring, 12-year-old SERC student Samantha Reed decided to find out if the same thing could help humans.
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Grimy field work? Give it to the tourists.

Tuesday, July 12th, 2011

Ali Kishwar, a volunteer tourist from Pakistan, navigates the muddy terrain across from SERC's beaver pond with caution. (Credit: SERC)

For most people, summer vacation means stretching out on a beach in the South Pacific, touring the ruins of ancient Greece, or (for the more outdoors-inclined) hiking the Inca Trail in Peru. It does not usually entail wading through ankle-deep mud to measure the diameters of trees.

Paul Smith, a 63-year-old retired engineer, travelled to SERC all the way from the United Kingdom to do it. So did Ali Kishwar, a Pakistani doctorate student who took a break from studying medicinal plants at the University of Reading in Berkshire, also in the U.K. Smith and Kishwar joined a motley group of seven citizen scientists who paid to spend a week at SERC doing field work.
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