Posts Tagged ‘pollination’

Moth Brains

Saturday, March 7th, 2009

Just when you think you can’t bear wading through one more impenetrable paper in a research journal, you stumble across an experiment that makes you fall in love with science all over again. Who could possibly resist the image of researchers wiring up moth brains to study how they perceive flower odors wafting through the air?

The sacred datura, an impressive (and hallucinogenic and poisonous) U.S. native perennial that produces huge, white, trumpet-shaped, and irresistibly fragrant blooms, is the favorite nectar source of the tobacco hornworm moth. To find the food, the moths must recognize the faintest whiff of datura and then track the scent upwind to the flower. In return for the meal, the moths pollinate the plant. To learn how the moth pollinator reacts to the 60 different chemicals that comprise the plant’s irresistible perfume, biology geeks at The University of Arizona in Tucson engulfed 20 flowers with Reynolds® Oven Bags and sucked the air out of the bags into a charcoal filter to capture all the chemicals. Back in the lab, they created a solution of the chemicals and injected it into a gas chromatograph. The chromatograph separated the chemicals and spewed them out one by one into a branched tube—one branch led to a wired-up moth and the other to a machine that identified and recorded the individual chemicals as they breezed by. Speakers attached to this gizmo emitted a rapid pop-pop-pop-pop sound if the moth was turned on by a chemical. Turns out the moth brains “popped” to only nine chemicals from sacred datura’s complex bouquet.

The scientists proceeded to study how 420 moths behaved toward the chemicals by putting a moth at one end of a wind tunnel and an artificial flower made of white filter paper doused with datura odors at the other. The insects were not impressed by the chemicals if they were presented one at a time. But when all nine chemicals that had made the moth brains “pop” were put on a paper flower, they stuck out their tongues to imbibe nectar, just as they would when faced with a real sacred datura flower.

Lead researcher Jeffrey A. Riffell’s first-hand account of the experiment is in today’s Science Daily. The paper, “Characterizing and Coding of Behaviorally Significant Odor Mixtures,” is in the current issue of the journal Current Biology. The title alone makes a persuasive case for the value of science journalism.

Missing Bees — How You Can Help

Monday, February 23rd, 2009

About a decade ago, bee biologists began to observe that several wild bumble bee species were declining dramatically. Three of them were important crop pollinators: the western bumble bee, once one of the three most common bumble bees in the western U.S. and Canada, the rusty patched bumble bee, which was widespread in 26 eastern and midwestern U.S. states and two Canadian provinces, and the yellowbanded bumble bee, which was frequently found throughout the east and upper Midwest of the U.S. as well as most of southern Canada. A fourth, Franklin’s bumble bee, historically had a small range in southern Oregon and northern California and may now be extinct.

What caused the decline? Commercial rearing of bumble bees for crop pollination may be the culprit. Bumble bee expert Robbin Thorp believes that members of these closely related species probably caught a disease from a European bee in the same rearing facility. The North American bumble bees would have had no resistance to the pathogen, which then spread to wild populations.

The Xerces Society is asking citizen monitors as well as scientists to be on the lookout for these species and report back with any findings. You can find photos, identification tips, information on the life history and habits of the bees, and contact information in the Bumble Bees in Decline section of their website. 

How Valuable Are Pollinators?

Wednesday, September 17th, 2008

Here’s a statistic that will come in handy next time you’re at a one of those cocktail parties where somebody pooh-poohs biological diversity by asking “Who needs insects anyway?” According to a paper in the journal Ecological Economics, the economic value of pollinators, especially bees, is about $217 billion a year. As reported in Science Daily, the study suggests that if it continues, the current decline of pollinators worldwide will have the biggest effect on fruits and vegetables, followed by oilseed crops. Crops that generally don’t depend on pollinators, such as cereals, sugar cane, and spices, would suffer fewer adverse affects.

Be a Bee Watcher

Thursday, June 5th, 2008

Well, after years of writing about bee watching, I’m now an official Bee Watcher. Twice a month, from spring through fall, I’ll be observing which bee species visit six native wildflowers I’ve planted on the roof of my Manhattan apartment building: common sunflower, woodland sunflower, mountain mint, milkweed, beebalm and goldenrod. I’m part of a New York City citizen science program that hopes volunteers like me can help researchers understand the challenges facing these essential pollinators, among them parasitic wasps and the mysterious Colony Collapse Disorder, which continued to decimate managed honeybee hives over the winter. There has been a lot of focus on honeybees of late, but surprisingly little is known about native bee species. Although they are also believed to be declining, there is little hard data to back this up, because most museum bee collections were made before World War II.

Being a Bee Watcher has its advantages. I’ve gotten free seeds and plants, and I’ve even learned a few things – for example, that North America has a very rich bee fauna, even relative to the tropics. This now includes 26 known introduced bee species in the U.S. and probably more – some of which are potential pests. And who knew that although butterflies and moths (except for migrants) tend to be sparse in urban habitats like mine, bees apparently take much better to city living?

The New York City Bee Watcher program is an outgrowth of the nationwide Great Sunflower Project, which is looking for volunteers. Which means you can be a bee watcher, too.  

A Rose by any Other Name Would not Smell as Sweet

Thursday, April 17th, 2008

And now, another reason why air pollution is bad. It not only wrecks our lungs but also destroys flower fragrance. According to a new study, the scent molecules produced by blossoms bond quickly with ozone and other pollutants, producing chemically altered aromas that no longer smell like flowers. This, according to the researchers, could at least partially explain why wild populations of pollinators, especially bees, are declining in some areas, including California.