Featured Research

from universities, journals, and other organizations

Phased-Out Bt Corn Variety Dramatically Cut Growth Rate Of Black Swallowtail Caterpillars

Date:
September 13, 2001
Source:
University Of Illinois At Urbana-Champaign
Summary:
Pollen from a Bt corn variety carrying a now-phased-out genetically inserted pesticide known as event 176 dramatically reduced growth rates among black swallowtail caterpillars in University of Illinois field tests, researchers report.

CHAMPAIGN, Ill. — Pollen from a Bt corn variety carrying a now-phased-out genetically inserted pesticide known as event 176 dramatically reduced growth rates among black swallowtail caterpillars in University of Illinois field tests, researchers report.

Related Articles


Because rainfall repeatedly reduced pollen concentrations during the summer 2000 test period, the results “must be considered conservative,” the scientists said.

The findings and those of five other related projects done elsewhere, and which also targeted Bt corn, appear online this week in the Proceedings of the National Academy of Sciences. The papers are being released ahead of publication at the request of the U.S. Environmental Protection Agency.

“The results of this study suggest that pollen from Bt corn varieties engineered with the 176 event may have sublethal effects on black swallowtails (Papilio polyxenes) feeding on host plants situated outside of cornfields,” the authors wrote. Researchers also attempted to study the effects on monarch butterflies (Danaus plexippus), but a high death rate was believed to be more likely the result of predation than proximity to pollen.

Bt corn refers to genetically modified varieties that resist the European corn borer (Ostrinia nubilalis). Bt is short for Bacillus thuringiensis, a soil organism that produces toxic proteins that kills the borers, which cause $1 billion in crop damage annually in the United States. Scientists can control when and in what part of the plant the toxin is produced by combining gene sequences with specific promoters. Successful transformations of corn with the genetically engineered sequences are called “events.”

The UI team, led by entomologists May R. Berenbaum and Arthur R. Zangerl, planted Novartis Max 454 Bt corn, which contains Novartis event 176, in a 30-by-30 meter tract northeast of the UI campus in late May 2000.

This variety of Bt corn is known to produce pollen with higher concentrations of the pesticide than other varieties and has been linked to a reduced survival of monarchs at concentrations naturally occurring in and near cornfields. (Registration of event 176 expires this year and renewal is not expected, the authors noted. Less than 1 percent of U.S. corn acreage in 2000 contained event 176.)

Researchers put 20 potted parsnip plants and 25 potted milkweeds at intervals ranging from one-half meter to 7 meters from the corn when it began shedding pollen in late July. Pollen levels were monitored. Black swallowtails were released to feed on the parsnip and the monarchs on the milkweed, which attracted more predators.

The disappearance of monarch larvae was rapid over the next six days, but the disappearance was not affected by proximity to the crop, Zangerl said. The death rate was lower among black swallowtails and again unaffected by proximity. However, he said, the growth rate of the swallowtails varied dramatically; larvae 7 meters from the corn were three times as large as the larvae located one-half meter away from the corn.

UI researchers last year had reported high death rates of black swallowtail larvae fed high concentrations of event 176-containing corn pollen in laboratory tests. The new study shows that much lower levels can cause significant mortality in the laboratory.

The earlier study also noted that a widely used Bt corn variety containing Monsanto event 810 had no adverse affect on black swallowtails living in weeds near cornfields (see http://www.news.uiuc.edu/news/00/0605btcorn.html).

“Results of this new study tell us again that careful event selection by producers is advisable,” Berenbaum said. “Our findings also suggest that much more research is needed on each new Bt variety to make sure non-target species will not be adversely affected once it is planted in the field.”

Co-authors are Berenbaum, Zangerl, graduate students Duane McKenna and Mark Carrol, and undergraduates C. Lydia Wraight, Peter Ficarello and Rita Warner. The UI Foundation and Center for Advanced Study funded the research.

Berenbaum, a member of the NAS, served as the editor of the six related papers.


Story Source:

The above story is based on materials provided by University Of Illinois At Urbana-Champaign. Note: Materials may be edited for content and length.


Cite This Page:

University Of Illinois At Urbana-Champaign. "Phased-Out Bt Corn Variety Dramatically Cut Growth Rate Of Black Swallowtail Caterpillars." ScienceDaily. ScienceDaily, 13 September 2001. <www.sciencedaily.com/releases/2001/09/010911072733.htm>.
University Of Illinois At Urbana-Champaign. (2001, September 13). Phased-Out Bt Corn Variety Dramatically Cut Growth Rate Of Black Swallowtail Caterpillars. ScienceDaily. Retrieved October 26, 2014 from www.sciencedaily.com/releases/2001/09/010911072733.htm
University Of Illinois At Urbana-Champaign. "Phased-Out Bt Corn Variety Dramatically Cut Growth Rate Of Black Swallowtail Caterpillars." ScienceDaily. www.sciencedaily.com/releases/2001/09/010911072733.htm (accessed October 26, 2014).

Share This



More Plants & Animals News

Sunday, October 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Black Bear Cub Goes Sunday Shopping

Black Bear Cub Goes Sunday Shopping

Reuters - Light News Video Online (Oct. 23, 2014) Price check on honey? Bear cub startles Oregon drugstore shoppers. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Dances With Wolves in China's Wild West

Dances With Wolves in China's Wild West

AFP (Oct. 23, 2014) One man is on a mission to boost the population of wolves in China's violence-wracked far west. The animal - symbol of the Uighur minority there - is under threat with a massive human resettlement program in the region. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
Breakfast Debate: To Eat Or Not To Eat?

Breakfast Debate: To Eat Or Not To Eat?

Newsy (Oct. 23, 2014) Conflicting studies published in the same week re-ignited the debate over whether we should be eating breakfast. Video provided by Newsy
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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