Featured Research

from universities, journals, and other organizations

Trouble In Paradise? "Natural" Pest Control Requires Careful Planning, Science Authors Conclude

Date:
August 17, 2001
Source:
American Association For The Advancement Of Science
Summary:
Mixing exotic plants and animals with native species doesn’t always lead to a happy ending, especially in the tropical paradise of Kauai Island, Hawaii. Biocontrol—the introduction of real organisms to control pests—can lead to community-wide ecological harm if not planned carefully, researchers report 17 August 2001 in the international journal, Science.

Mixing exotic plants and animals with native species doesn’t always lead to a happy ending, especially in the tropical paradise of Kauai Island, Hawaii. Biocontrol—the introduction of real organisms to control pests—can lead to community-wide ecological harm if not planned carefully, researchers report 17 August 2001 in the international journal, Science.

Some agricultural experts, foresters and conservationists favor biocontrol over chemical solutions such as insecticides and pesticides to eradicate or maintain weeds, bugs, and sometimes disease. Yet, if not tested properly beforehand, in a community-wide context, introduced species can do more harm than the plant or animal they target, the new study suggests.

Jane Memmott and M. Laurie Henneman of the University of Bristol in the United Kingdom bring new scientific insights to the ongoing debate concerning widespread impacts of biocontrol.

The use of biocontrol to fight pests—and even invasive species, the second largest problem in biodiversity and conservation, next to habitat destruction—has clear environmental benefits, Memmott emphasized. But, she added, a biocontrol agent gone wild may have the potential to impose adversely cascading events in the food chain, either directly or indirectly.

Since 1945, Hawaii has had a history of non-native, or exotic species being purposefully introduced into the ecosystem. Memmott and Henneman wanted to examine, in a calculable way, the degree to which certain biocontrol species are interacting with native species. So, they constructed food webs of Hawaiian plants, butterflies and moths, and parasitoids.

The Lepidoptera (butterflies and moths) feed on the plants. Parasitoids, such as alien wasps, lay eggs on the bodies of Lepidoptera caterpillars, causing an early death before the parasite larvae metamorphose into winged insects. Researchers wanted to map out exactly “who eats what,” to keep track of the real impact of non-native species on the Hawaiian island of Kauai.

The food webs, which drew lines between the three members of the food web—plants, Lepidoptera and parasitoids—provide scientists with real numbers to draw conclusions about the proportions of organism types that depended on another for reproduction or food. These food webs allow ecologists to establish how much an alien parasitoid species has penetrated the food chain, and to predict the direct and indirect effects of biocontrol agents on species. These webs open up doors for more meaningful research to take place, according to the biologists.

Memmott and Henneman collected over 2,000 caterpillars, which they checked for parasitoids. Some 20 percent of the caterpillars died from parasitoid attacks, the majority of which were biological control agents people had introduced to fight pests. Accidentally introduced, or immigrant wasps, constituted the next most lethal group of parasites. Because native parasites only constituted three percent of all parasitoids, they were responsible for low levels of mortality, overall.

The food web approach to this ecological question still provides only a “snapshot” of the whole story, Memmott said, because the most vulnerable Lepidoptera species may have already disappeared from the radar screen. The low number of native parasitoids also presents a puzzle, because it is not known if the alien wasps out-competed the natives, or if the natives were already small in number.

“Some of the biocontrol agents released in early biocontrol programmes have left the agricultural habitats in which they were released, and turned to attacking native species,” Memmott noted. “However, no agents released post-1945 were found in the web, suggesting that biocontrol may be much safer today than in the past.”

Memmott and Henneman expressed the “critical importance” of completely understanding the ecological costs of biocontrol species over the species that humans intend to target, in Hawaii and elsewhere.

Support for this research was provided by the Leverhulme Trust Foundation, UK; as well as the University of Hawaii Department of Entomology; the State of Hawaii Department of Land and Natural Resources; and Kokee State Park.


Story Source:

The above story is based on materials provided by American Association For The Advancement Of Science. Note: Materials may be edited for content and length.


Cite This Page:

American Association For The Advancement Of Science. "Trouble In Paradise? "Natural" Pest Control Requires Careful Planning, Science Authors Conclude." ScienceDaily. ScienceDaily, 17 August 2001. <www.sciencedaily.com/releases/2001/08/010817081808.htm>.
American Association For The Advancement Of Science. (2001, August 17). Trouble In Paradise? "Natural" Pest Control Requires Careful Planning, Science Authors Conclude. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2001/08/010817081808.htm
American Association For The Advancement Of Science. "Trouble In Paradise? "Natural" Pest Control Requires Careful Planning, Science Authors Conclude." ScienceDaily. www.sciencedaily.com/releases/2001/08/010817081808.htm (accessed July 23, 2014).

Share This




More Earth & Climate News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Observation Boat to Protect Cetaceans During Ship Transfer

Observation Boat to Protect Cetaceans During Ship Transfer

AFP (July 22, 2014) As part of the 14-ship convoy that will accompany the Costa Concordia from the port of Giglio to the port of Genoa, there will be a boat carrying experts to look out for dolphins and whales from crossing the path of the Concordia. Duration: 01:02 Video provided by AFP
Powered by NewsLook.com
New Orleans Plans to Recycle Cigarette Butts

New Orleans Plans to Recycle Cigarette Butts

AP (July 21, 2014) New Orleans is the first U.S. city to participate in a large-scale recycling effort for cigarette butts. The city is rolling out dozens of containers for smokers to use when they discard their butts. (July 21) Video provided by AP
Powered by NewsLook.com
Shark Sightings a Big Catch for Cape Tourism

Shark Sightings a Big Catch for Cape Tourism

AP (July 21, 2014) A rise in shark sightings along the shores of Chatham, Massachusetts is driving a surge of eager vacationers to the beach town looking to catch a glimpse of a great white. (July 21) Video provided by AP
Powered by NewsLook.com
Spectacular Lightning Storm Hits London

Spectacular Lightning Storm Hits London

AFP (July 19, 2014) A spectaCular lightning storm struck the UK overnight Friday. Images of lightning strikes over the Shard and Tower Bridge in central London. Duration: 00:23 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins