The beetles, each roughly the size of a sesame seed, are part of a broad strategy to combat the relentless mile-a-minute vine, which has invaded parks and forests from North Carolina to Massachusetts and as far west as Ohio.
Known scientifically as Rhinoncomimus latipes, the insects are considered biological control agents by invasive plant experts and are to be released at two places each in the Bronx and Queens and one on Staten Island.
The vines were first spotted in Pelham Bay Park in the Bronx in 2006. "When we saw that mile-a-minute was growing there, we panicked," said Katerli Bounds, the director of forest restoration for the city's Department of Parks and Recreation. The park, she said, contains one of the best examples of natural forest in the city.
In 2007, the department received a grant from the State Department of Environmental Conservation to eradicate mile-a-minute from Pelham Bay Park. That campaign included the limited use of herbicides but chiefly involved teams of volunteers spending thousands of hours weeding out the vines. Those efforts, which continue, were not enough, Ms. Bounds said.
Mile-a-minute vine is native to Asia, but it is believed that at some point in the 1930s, its seeds contaminated a shipment of holly seeds in Japan, said Judy Hough-Goldstein, a professor of entomology and wildlife ecology at the University of Delaware at Newark. Dr. Hough-Goldstein, who studies the relationship between insects and mile-a-minute, said those holly seeds were shipped to a nursery in York, Pa.
The vine has triangular leaves and can grow up to 20 feet in a single growing season, creeping up and over nearby plants and trees. Under ideal conditions, a single plant can produce thousands of seeds, which can germinate in the soil for up to six years after falling to the ground.
"The spread of mile-a-minute is strongly tied to soil disturbances," Dr. Hough-Goldstein said. Walking paths, roadsides, fallen trees — almost any exposed bit of ground will do.
On a recent sultry summer morning, Ms. Bounds pushed through a nearly shoulder-high wall of herbaceous plants, shrubs and small trees in a particularly lush area of Pelham Bay Park not far from the Orchard Beach parking lot. When she stopped, there was no need to point; a sprawling, strangulating net of mile-a-minute covered hundreds of plants. If nothing is done to curb the vine's spread, native plants like aster, goldenrod and pokeweed stand little chance of survival, she said. The vine can suppress saplings' growth and even lead to the death of mature trees.
"For a forest to remain healthy, you really need many varieties of native plants to survive and thrive," Ms. Bounds said. "You don't want a monoculture."
Plants and animals from foreign lands can take advantage of new ecosystems because they usually enter without the natural predators that have evolved with them. In 1996, entomologists began trying to identify insects that depended on the vine for food. After years of work, some of it in China and Japan, they finally zeroed in on R. latipes.
Dr. Hough-Goldstein then led five more years of research in special federal Department of Agriculture quarantine facilities at the University of Delaware to ensure that the weevil fed only on mile-a-minute. Her findings determined that the weevil's entire life cycle — from egg to larva, pupa and adult — was solely dependent on mile-a-minute. In 2004, the Department of Agriculture granted permission for the use of R. latipes as a biological control.
The weevils destined for New York were bred at the Phillip Alampi Beneficial Insect Rearing Laboratory in West Trenton, N.J., part of the New Jersey Department of Agriculture. In small, beige rooms filled with clear plastic containers, many generations of R. latipes are raised each year.
In the oviposition room, males and females are left undisturbed to mate on bushy mile-a-minute plants grown on site in a greenhouse. "We choose the plants with the thickest stems and the most growing tips because we want the plants to be the most delicious and ideal to lay eggs on," said Cyndi Detweiler, an entomologist at the lab.
The New York weevils were in the development room. But they were still tiny larvae and pupae burrowed away in the stems of the vine or the soil at the bottom of the container, roughly a week from becoming mature adults.
Since 2004, the lab has sent more than 500,000 weevils to 11 states, including New York. Mark Mayer, another entomologist at the lab, cautioned that biological control agents were not the only answer. "The weevils have substantially reduced mile-a-minute at many original release sites, but it will never be eradicated," he said.
Back in Pelham Bay, Ms. Bounds talked about the bigger picture and the role of the parks department.
"The term 'forest restoration' begs the question — what are you restoring to? The point isn't to go back; the point is to go forward," she said. "We know that we can't eradicate all invasive plants, but what we can do is hold them at bay long enough for the native populations to build back up again."
Anda sedang membaca artikel tentang
Urgent Task for Insect: Stop a Relentless Vine
Dengan url
https://scienceteko.blogspot.com/2013/08/urgent-task-for-insect-stop-relentless.html
Anda boleh menyebar luaskannya atau mengcopy paste-nya
Urgent Task for Insect: Stop a Relentless Vine
namun jangan lupa untuk meletakkan link
Urgent Task for Insect: Stop a Relentless Vine
sebagai sumbernya
0 komentar:
Posting Komentar