Posts Tagged ‘Fly Control’

Tale of the Headless Dragonfly: Ancient Struggle, Preserved in Amber

In a short, violent battle that could have happened somewhere this afternoon, the lizard made a fast lunge at the dragonfly, bit its head off and turned to run away. Lunch was served.


Headless dragonfly. This ancient species of dragonfly is seen largely intact in amber, missing only a few feet and its head – presumable in the mouth of the lizard seen fleeing at the left. (Credit: Photo by George Poinar)

But the battle didn’t happen today, it happened about 100 million years ago, probably with dinosaurs strolling nearby. And the lizard didn’t get away, it was trapped in the same oozing, sticky tree sap that also entombed the now-headless dragonfly for perpetuity.

This ancient struggle, preserved in the miracle of amber, was just described by researchers from Oregon State University in Paleodiversity, a professional journal. It announced the discovery of a new sub-family of dragonflies in the oldest specimen of this insect ever found in amber.

More importantly, the study and others like it continue to reveal the similarities of behaviors and ecosystems separated by many millions of years, said George Poinar, a professor emeritus at Oregon State University. Poinar is one of the world’s leading experts on life forms found preserved in this semi-precious stone that acts as a natural embalming agent.

“Dragonflies are still eaten by small lizards every day, it’s a routine predator/prey interaction,” Poinar said. “This shows once again how behaviors of various life forms are retained over vast amounts of time, and continues to give us insights into the ecology of ancient ecosystems.”

Dragonflies are one of the world’s more colorful, interesting and successful insects, Poinar said, having managed to survive for a very long time. This is the oldest fossil ever found in amber, but other stone fossil specimens of dragonflies date back as much as 300 million years, including some that were huge, with wingspans up to three feet.

Amber is a semi-precious stone that originates as the sap from certain trees. Later fossilized through millions of years of pressure, it’s unique for the ability to capture and preserve in near-lifelike form small plant, animal or insect specimens that provide data on ancient ecosystems.

“Dragonflies are now, and probably were then, very quick, evasive, and greedy predators,” Poinar said. “They feed on other larvae and insects, mosquitoes, gnats, lots of things. Some are quite beautiful, very popular with insect collectors. And some modern populations like to migrate regionally, going south to mate.”

But as the new amber specimen shows, dragonflies are now and for a long time have also been prey, particularly of small lizards. Young and hatchling dinosaurs also probably dined on them, Poinar said.

The quick and merciless battle preserved in this stone took place in the Early Cretaceous somewhere between 97 million to 110 million years ago in the jungles of the Hukawng Valley of Burma, now known as Myanmar. The dragonfly — with one notably missing part — is preserved almost perfectly. Only the foot and tail of a small lizard remains in the stone, presumably as the animal was trying to flee.

“It’s unfortunate we don’t have the entire specimen of the lizard, because it probably had the dragonfly’s head in its mouth,” Poinar said. “Both died when they were trapped in the tree sap in the middle of this duel.”

Like a never-ending feud, these battles are still going on today. Scientists have documented in some sites near waterfalls in Costa Rica that there are many dragonflies of a certain species. But if lizards are present, there are no dragonflies — it appears they all get eaten.

Sometimes things change. Sometimes they don’t.

 

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Asian fruit fly may plague state next year

A spotted wing drosophila stands on a raspberry leaf at Upper Mountain Research Station in Ashe County

RALEIGH — An Asian fruit fly recently discovered in North Carolina could create problems next year for gardeners and commercial farmers who grow small fruits such as blueberries and apples.

A county extension agent in Asheboro this past summer captured the state’s first confirmed spotted wing drosophila in a trap in her backyard. The fruit fly, native to cooler parts of east Asia, was discovered in the mainland United States in California in fall 2008. By 2009, it had appeared in Florida, said Hannah Burrack, an extension specialist and assistant professor of entomology at N.C. State University.

“We don’t have a clear idea of how it got into the U.S.,” Burrack said.

A taste for soft skin

Fruit flies typically feast on the fungus of rotting fruit, Burrack said, which is why they appear in your kitchen near overripe bananas. But the spotted wing drosophila feeds on fresh, soft-skinned fruits, which means it can cause much more damage. The Asian pest is capable of destroying 20 percent of a fruit crop.

After its appearance in Florida, Burrack organized a trapping project in North Carolina, South Carolina and Virginia to gauge the fly’s migration. Adult flies were trapped during the summer, and the first significant North Carolina larval infestation was discovered in September at the Upper Mountain Research Station in Ashe County, in the northwest corner of the state.

The flies found this year were discovered after most of the state’s small fruit had been harvested, so their true effect won’t begin to be felt until next year.

“It’s going to be another added challenge that growers have to deal with,” said Burrack, who emphasized that common insecticides have been effective with spotted wing drosophila on the West Coast.

But fighting the flies could mean a change in routine for backyard gardeners, said Mary Helen Ferguson, the Randolph County extension agent who trapped the first fly.

“There are so few problems with blueberries that most gardeners would never need to spray a blueberry plant,” Ferguson said.

The flies have not been confirmed on commercial farms, although there have been reports that need to be investigated.

“It’s causing significant issues for the folks on the West Coast,” Burrack said. In North Carolina, “we’ll see where it shows up and in what numbers next year.”