As superheroes go, the tiny insect that Ellen Lake holds in her outstretched hand seems preposterous.
For starters, it's no bigger than a speck of dirt.
In magnification, with its bizarre long snout, the insect - a weevil known as R. latipes - looks almost comical, like something Dr. Seuss would have created.
Here's what it's up against: a barbed vine aptly named mile-a-minute. It can grow 20 feet in a summer. It engulfs landscapes, blanketing fields and shrubs, climbing trees, snuffing out plant life. Ultimately, the related and complex web of bugs, birds and other species fades as well.
Yet despite what look like long odds in the battle of weevil vs. weed, the little guy appears to be winning.
If it does, it will be another success story among a proliferating hit squad of imported insects fighting invasive bugs and plants in the United States.
The new Pangaea
The problem of invasive species is daunting.
With ever-increasing global trade and travel has come an onslaught of foreign species. Some that have no natural enemies here go on the rampage.
Land managers have fought back, yanking weeds, squishing bugs, and showering them with herbicides or pesticides.
But money runs out, nobody likes the chemicals, and none of it is more than a stopgap anyway.
So managers have turned to a technique more than a century old, but gaining in sophistication and acceptance.
It's called biological control, and at its basis is the knowledge that the natural world is also a violent one. Every species has its enemies. And they can be recruited.
By now, hundreds of biological control agents have come into the United States, said Edwin Rajotte, an entomology professor at Pennsylvania State University.
These agents can be as common as the milky spore used to kill lawn grubs and as rare as the tiny wasp that researchers are releasing this year in the hope it thwarts the emerald ash borer, which has killed 25 million ash trees and has spread to Pennsylvania.
With so many invasives making their way here and so many biocontrol agents following, "we're re-creating Pangaea," said Dennis Burton, executive director of the Schuylkill Environmental Education Center in Roxborough, in a reference to Earth's original supercontinent.
"We're bringing all the species back together," he said. "It's the new hope."
A hungry helper
Mile-a-minute had a big head start. It came to the United States in 1938, in a batch of holly seeds mailed to a York County nursery. The grower thought the strange vine that sprouted looked interesting, so he let it mature. It produced seeds.
Now the plant has spread to 11 states, maybe 13.
By 1996, enough was enough. The U.S. Forest Service initiated a search for a control.
In China, mile-a-minute's home turf, researchers sought out native patches so they could examine the plant for insects, fungi and pathogens.
What kept the vine in check?
Researchers sifted through 111 species.
Among them, R. latipes - officially, Rhinoncomimus latipes - looked promising.
The weevil was abundant and effective. Adults ate the plant's leaves, then laid eggs. When the larvae emerged, they tunneled inside and gobbled the plant's innards.
The bug was hungry. That was good. But researchers needed to make sure it wouldn't want a more expansive diet, one that might include valuable American crops.
This had been a hard lesson in biocontrol. Probably the best-known fiasco is the case of the 102 cane toads sent to Australia to control a beetle pest of sugar cane. The toads never ate the beetles, but they consumed just about everything else.
In China, the researchers carefully fed R. latipes 49 species of plants.
The weevil would have none of them. In 2000, it was brought to the United States.
Killer on the loose
It fell to Richard Reardon, a program manager with the U.S. Forest Service, to find someone to run the weevil through some more trials.
He contacted Judy Hough-Goldstein, a University of Delaware professor of entomology.
She worked near the U.S. Department of Agriculture's Beneficial Insects Introduction Research Unit, which has a quarantine lab.
There, Hough-Goldstein monitored what happened as scientists fine-tuned their examination of the weevil's diet, tempting it with 28 more plant species.
They needed to be sure their weevil was "host-specific" - that it would eat only the target plant.
If the beetle failed the test, it would be dispatched to the autoclave, just like the kudzu beetle that wound up liking soybeans.
But again, R. latipes had an appetite only for mile-a-minute. In fact, the weevil wouldn't even lay its eggs on the wall of its rearing container. It insisted on laying them on the plant. The researchers concluded it would probably die before it would eat a plant other than mile-a-minute.
In 2004, four years after R. latipes arrived, federal officials gave the nod to turn the weevil loose. The next step was to start raising R. latipes in bulk.
Researchers turned to New Jersey's Phillip Alampi Beneficial Insect Rearing Laboratory.
That year, in rooms that are temperature- and humidity-controlled, the lab raised enough weevils for Hough-Goldstein to release 600 in New Jersey and Delaware.
This year, the lab is producing 7,000 a month.
At last count, more than 66,000 weevils have been released at 61 sites in New Jersey, Pennsylvania, Delaware, Maryland and West Virginia.
Exciting times
Researchers hope for a success akin to that of the beetle that tackled purple loosestrife, a weed that has choked many of the region's wetlands and is held at least partly responsible for declines among the endangered bog turtle.
Since 1997, more than 1.6 million Galerucella beetles have been let loose at 93 sites in New Jersey alone. And they've done their job. The plants no longer dominate those ecosystems, said Mark Mayer, the Trenton lab's supervising entomologist.
It has gotten to the point where Mayer can look at a stand of purple loosestrife and appreciate its beauty. "I used to hate that plant," he said. "Now it looks nice. It's part of the environment."
It can - and in the case of R. latipes, did - take a decade to put a bug through its paces, from discovery to release. The cost can run into the millions.
But if the weevil works, it will work in perpetuity for free.
"It's exciting times for biocontrol," Reardon said. In addition to R. latipes, he's keeping a hopeful eye on several weevil species that might work against garlic mustard and a parasite that attacks Japanese knotweed.
'Go, weevils!'
On an overcast day, Ellen Lake, a University of Delaware graduate student working on the weevil project, and an assistant, Kimberley Shropshire, waded through the weeds at the Brandywine Valley Association's Myrick Conservation Center in Chester County.
A little more than two years ago, 450 specimens of R. latipes were released here.
Within seconds, the two women spotted their first weevil. Then more.
They found its orange eggs. They saw stem damage from the larvae and holes in the leaves.
What the women don't know is what will happen next. They don't think the weevil will be appetizing to native species, but they don't know for sure. An ecological system is complicated, and critics of biocontrol wish potential ripple effects were studied more.
Given the threat of invasives, many say biological control is worth the risks that supporters insist are minimal.
"There are consequences to everything you do, including nothing," said Chris Dionigi, assistant director of the National Invasive Species Council, a government agency. "Often, with invasive species, doing nothing results in the greatest impact."
A week and a half ago, Hough-Goldstein stood before a group of experts at an invasive-plants conference at the University of Pennsylvania, providing an update on R. latipes. The prognosis was good.
"A lot of plant mortality this year," she said. "Go, weevils!"
Either way, not even the most optimistic think the weevil will expunge mile-a-minute from the landscape. The idea is to restore balance.
"It's kind of like an arms race," Dionigi said.
Best-case scenario: The weevils will knock back mile-a-minute and then, with few host plants, decline themselves. Then the weed will gain ground, but soon the remaining weevils will proliferate. And so on.
Researchers won't announce a winner in the war of the weevil and the weed until the insect proves it can reduce mile-a-minute so it is no longer out of control.
As Hough-Goldstein finished her talk at Penn, she mentioned she was looking for new release sites. Lake, sitting in the audience, noticed a flurry of land managers reaching for their business cards.
"There are many people," Lake said with a grin, "willing to donate their patch of mile-a-minute to science."Philadelphia Inquirer
