Fruit Fly Diversity Is in the Details

Many scientists attribute the diversity of plant-feeding insects to plant diversity and to the many ways insects can survive on host plants. An article published this week in Science explores how these niches are used by one group of insects—and also examines evidence that using niche diversity alone to estimate species diversity can result in an undercount. The authors conclude that for this insect group, diversity is greater than the sum of plant parts.

Molecular biologist Sonja Scheffer, in the Agricultural Research Service (ARS) Systematic Entomology Laboratory in Beltsville, Md., teamed up with three colleagues to study the ecological links between tropical fruit flies in the Blepharoneura genus and their host plants. The other researchers were Marty Condon, a biology professor at Cornell College in Mount Vernon, Iowa; ARS support scientist Matthew Lewis, and Susan Swenson, a biology professor at New York’s Ithaca College.

Blepharoneura fly larvae feed within the flowers or fruits of plants in the cucumber family. For their study, the researchers collected and raised 2,857 different Blepharoneura specimens from 24 neotropical host plant species. DNA analysis indicated there were at least 52 distinct species in the collection.

The researchers found that only one of the fruit fly species they raised ate two kinds of plant parts—seeds and flowers. All the others ate only one or the other, and many of the flower-eaters were so specialized that they ate only male or only female flowers.

Most of the fly species were associated with only one host plant species. On the other hand, many of the plants hosted a range of species. One plant species supported at least 13 species of the fruit flies.

Location also played a role in the findings. Some of the fly species were geographically widespread. But others could only be found within a limited geographic range, even though the range of the host plant was much more extensive.

The team concluded that host plant and niche diversity plays a significant role in the extraordinary diversity of Blepharoneura flies. But geographical factors—and the passage of time—may play an even greater role.

ARS is the U.S. Department of Agriculture's chief scientific research agency.

Ozone Might Help Make Bee Hives Cleaner and Safer

Ozone, which is already used to sanitize drinking water and swimming pools, might help make hives cleaner and safer for America's beleaguered honey bees. That's according to results from preliminary laboratory tests by Agricultural Research Service (ARS) entomologist Rosalind R. James. She leads the agency's Pollinating Insects Biology, Management and Systematics Research Unit at Logan, Utah.

James tested ozone's effects on two pesticides, coumophos and tau-fluvalinate, both widely used by beekeepers to control varroa mites, a major enemy of bees. Studies elsewhere indicate that residues of these chemicals can accumulate in hives, including in the honeycomb. Beekeepers typically reuse the honeycomb after the honey has been extracted.

For the experiment, she placed glass vials of the pesticides in a small, tightly sealed chamber, then exposed the chemicals to a flow of ozone gas. Keeping the chamber at 50 percent relative humidity, she tested different temperatures and different ozone and pesticide concentrations.

Applying 500 parts per million of ozone in an approximately 93 degree Fahrenheit chamber for 10 to 15 hours degraded low concentrations of both pesticides, but 20 hours were needed to break down higher concentrations of tau-fluvalinate.

James also looked at ozone's ability to zap the greater wax moth, a honeycomb pest, in all of its life stages, from egg to adult. Wax moths attack bee young and damage the honeycomb.

Young wax moth larvae and adults were killed by just a few hours of ozone exposure. However, eggs, the most resistant life stage, had to be exposed to the gas for a few days.

Further tests are needed to find out whether the breakdown products of the degraded pesticides pose a hazard to bees, James noted.

In related work, James is finding that ozone can destroy microbes that cause major bee diseases such as chalkbrood and American foulbrood, but much higher ozone concentrations and longer fumigation times are needed.

ARS, along with the National Honey Board, headquartered in Firestone, Colo., and O3Co., Inc., of Idaho Falls, Idaho, provided research support.

ARS is the U.S. Department of Agriculture's chief scientific research agency.

U.S. Sunflowers Could "Get a Lift" from Down Under

Improved disease resistance could be in store for tomorrow's sunflower hybrids, thanks to plants that Agricultural Research Service (ARS) scientists collected in Australia last year and are now evaluating in greenhouse trials in Fargo, N.D.

ARS plant pathologist Tom Gulya and botanist Gerald Seiler traveled to Australia in early 2007 in hopes of identifying new genes that could be incorporated into American sunflower hybrids for improved resistance to fungal diseases including downy mildew, rust and Sclerotinia stalk rot.

Gulya considers stalk rot enough of an economic threat to the U.S. sunflower crop that incorporating even partial resistance from the Aussie plants would be worthwhile. He and Seiler, who are both in the ARS Sunflower Research Unit at Fargo, made the trip with funding from the ARS Plant Exchange Office. With the assistance of a team from the Department of Primary Industries and Fisheries (DPIF) in Queensland, Australia, Gulya and Seiler collected 59 populations of the wild sunflower species Helianthus annuus and H. debilis.

In the fall of 2007, they began greenhouse trials to evaluate the plants' fungal disease resistance, as well as to analyze their seed oil content and fatty acid composition. A University of British Columbia collaborator will compare the plants' genetic profiles to those of American wild sunflowers. This could reveal whether the Aussie sunflowers have undergone significant genetic changes since arriving in the Land Down Under more than 100 years ago from America.

Gulya and Seiler estimate their sunflower expedition took them on a journey of more than 6,200 miles through Western Australia, South Australia, New South Wales, Victoria and Queensland. On average, they and the DPIF team gathered 6,000 sunflower seeds per collection. This included plants from yards, hedgerows, municipal garbage dumps and other sites.

Read more about the research in the May/June 2008 issue of Agricultural Research magazine.

ARS is the U.S. Department of Agriculture's chief scientific research agency.

USDA Lab Renamed in Honor of Nobel-Winning Researcher

ITHACA, N.Y., May 12, 2008—A U.S. Department of Agriculture (USDA) laboratory here will be renamed today for a renowned USDA scientist who was awarded the Nobel Prize in Medicine along with two colleagues in 1968.

The U.S. Plant, Soil and Nutrition Laboratory (PSNL), operated by USDA's Agricultural Research Service (ARS), will be renamed The Robert W. Holley Center for Agriculture and Health during a ceremony today. ARS is USDA's chief intramural scientific research agency.

Holley, a former ARS scientist, shared the Nobel award with Har Gobind Khorana and Marshall W. Nirenberg. Holley is the only ARS scientist to receive a Nobel Prize. From 1957 until 1964, he worked for ARS as a research chemist at the PSNL, which is located on the Cornell University campus in Ithaca. Holley died in 1993.

Holley and his research team determined the molecular structure of transfer RNA from concentrated yeast cells, marking the first time that a nucleic acid from any living organism had been sequenced. The majority of this research was conducted by Holley’s research group at the ARS laboratory.

"Dr. Holley’s findings about the genetic structure of living organisms served as a crucial foundation for studies in genetics and genomics, which are essential for our agricultural research," said USDA Research, Education, and Economics (REE) Under Secretary Gale Buchanan. "His work helped us devise tools to search the genetic makeup of plants and animals for beneficial traits such as improved nutritional quality and disease resistance that we can use for developing improved varieties of food, feed and livestock."

Under the supervision of Holley Center Director Leon Kochian, scientists at the ARS lab in Ithaca conduct research that builds on the discoveries of Holley and his team. These studies employ cutting-edge technologies in genomics, molecular and statistical genetics, computational biology, biochemistry and physiology.

Using these tools, ARS scientists investigate ways to improve biologically-based integrated pest management, enhance plant nutritional quality, and improve plant resistance to unfavorable environmental conditions and diseases. A new $40 million facility is being designed for the Holley Center, and will support Holley’s legacy of research excellence.

Rep. Maurice D. Hinchey from New York’s 22nd District will speak at today’s ceremony. Other speakers include USDA-REE Under Secretary Buchanan, ARS Associate Administrator Antoinette Betschart, Kochian, and Steve Kresovich, Cornell University associate provost for life sciences and director of the Institute for Genomic Diversity.

Sizing up Teen Snacking

The effect of snacking on teenagers' dietary intakes of recommended nutrients and MyPyramid food groups has been examined, and the findings are both positive and negative. After analyzing the eating habits of more than 4,000 teenagers surveyed nationwide, Agricultural Research Service (ARS) scientists found that 90 percent reported eating one or more snacks in a day.

The study was led by nutritionist Rhonda Sebastian with the ARS Beltsville Human Nutrition Research Center at Beltsville, Md. The study has been published online and also appears in the May print issue of the Journal of Adolescent Health. ARS is the U.S. Department of Agriculture's chief scientific research agency.

The 12- to 19-year-old teenagers—who were selected to be representative of the U.S. population—reported everything they had eaten during a 24-hour time period while participating in the survey What We Eat in America/NHANES 2001-2004. Overall, snacking was found to enhance the intake of some MyPyramid food groups, but it also contributed to the intake of excess discretionary calories as added sugars and fats.

Among the highest snackers—those who consumed four or more snacks in a day—both boys and girls ate more than twice as much fruit as their non-snacking peers. Even so, almost three-quarters of those relatively high fruit eaters failed to meet their MyPyramid recommendation to consume 1½ cups to 2½ cups of fruit daily, depending on age, gender and activity level.

On the positive side, boys who snacked more often were significantly more likely than nonsnacking boys to meet the MyPyramid milk recommendation, which is to consume three cups daily for both boys and girls. High-snacking girls, however, were not more likely to meet the milk recommendation compared to nonsnackers.

Among all of the teenagers surveyed, snack foods on average accounted for 43 percent of the day's total intake of added sugars, which they consumed mostly as soft drinks, fruit drinks, candies, dairy desserts and cakes. The researchers concluded that replacing those snacks with more nutritious foods and beverages would help teenagers consume diets more in step with national recommendations.

Drought Makes Farmers Mind Their Peas and Corn

A continuing drought in parts of the Northern Plains is pushing more and more farmers in dry areas to rethink their crop choices. Of the past nine years, only three have been wet years for these areas.

Some of these farmers put a new CD into their computers earlier this year to help plan their spring plantings. The CD contains the third--and latest--version of the Agricultural Research Service’s (ARS) Crop Sequence Calculator, which was released in February.

Scientists at the ARS Northern Great Plains Research Laboratory in Mandan, N.D., developed the Crop Sequence Calculator. To date, they have sent more than 12,000 copies of the CD free to farmers, ranchers and educators worldwide.

The calculator is a decision tool that deals with 16 crops, including barley, flax, sunflower and crops grown to support grazing cattle. Corn was one of the six new crops added in the latest calculator.

The new calculator, which includes data from the relatively dry years of 2002 through 2005, shows that in dry years, the deep-rooting and water-thirsty corn grown after peas--which are shallow-rooting and light users of water--yields better than when grown after thirstier crops.

The new calculator includes data from the previous CD, version 2.2.5, collected during the relatively wet years of 1998 through 2000. The earlier version similarly showed that growing the deep-rooting sunflowers after peas promised the highest sunflower yield. Users can plug in the prices they expect to get for their crops each year and see predicted gross and net earnings per acre for various combinations of crops in rotation.

Each version of the Crop Sequence Calculator was based on data from growing 100 combinations of 10 crops, with four crops in common to both versions: canola, dry pea, spring wheat and sunflower. Now farmers and ranchers can evaluate those four crops for both wet and dry years.

The new CD can be ordered free online at: http://www.ars.usda.gov/Main/docs.htm?docid=13698

ARS is the U.S. Department of Agriculture's chief scientific research agency.

New Issue of Healthy Animals Now Online

The Agricultural Research Service (ARS) today posted a new issue of Healthy Animals at:

http://www.ars.usda.gov/is/np/ha/han33.htm

This quarterly online newsletter compiles ARS news and expert resources on the health and well-being of agricultural livestock, poultry and fish.

Each quarter, one article in Healthy Animals focuses on a particular element of ARS animal research. The current issue examines efforts to control the biting midges that spread bluetongue virus.

Other research highlighted in this issue includes:

• Nutritious, year-round forage for cattle
• Heat stress model helps keep cows cool
• Improved peanuts for forage and hay

Professionals interested in animal health issues may want to bookmark the site as a resource for locating animal health experts. An index lists ARS research locations covering approximately 70 animal health topics. These range from specific diseases, such as Lyme disease, to broad subjects like nutrition or parasites. The site also provides complete contact information for the more than 25 ARS research groups that conduct studies aimed at protecting and improving farm animal health.

To receive an e-mail alert about each future issue's posting online, contact Laura McGinnis, ARS Information Staff or sign up online.

ARS is the U.S. Department of Agriculture's chief scientific research agency.