From Sci-Fi to mosquito research a repellant odor to make humans disappear to mosquitoes


The  female Anopheles gambiae mosquito pictured at the right, shows her weapons researchers are trying to combat in this ancient war of man against mosquito. It is only the female mosquito that bites and can spread disease using these parts of olfactory (smelling) appendages (antennae, maxillary palps and proboscis) as so graphically seen in this electron micrograph image.

Dr. Leslie Vosshall and two colleagues at Rockefeller University published a series of experiments that seemed to settle the 50-year-old question of how the insect repellent DEET kept mosquitoes at bay (Science, 319:1838-42, 2008).

Vosshal explained their findings “It doesn’t smell bad to insects. It masks or inhibits their ability to smell you.”
The Bill & Melinda Gates Foundation funded the research to understand how and why DEET works. This is critical to creating the next generation of chemicals, which may head off insect-borne diseases such as malaria and dengue fever.
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Laurence Zwiebel of Vanderbilt University (also a Gates’ grantee) and  Ulrich Bernier of the US Department of Agriculture are not sure the findings just didn’t make sense, given everything they knew about this system

In Vosshall experiment,  the response of the mosquito’s olfactory neurons to two separate, attractive odors in human breath. Then, she combined each odorant with DEET in a single odor cartridge and noticed a smaller neural response. Vosshall believes DEET was blocking the mosquito’s olfactory co-receptor.
Another teams experiment another interpretation

Using gas chromatography, Leal confirmed his suspicions this year. When he repeated Vosshall’s experiment using separate odor cartridges that blended DEET and each attractive odor only at their tips, the mosquito’s neural response was no longer diminished. Then, Leal identified a 19-1DEET-sensitive odor receptor neuron and showed that mosquitoes avoid passing through a “curtain” of DEET vapors.
Leal’s paper surprised Vosshall, but is unconvinced by Leal’s results, and has been trying to reproduce the effect in her own lab. “Competition in science is good,” she says, “It can be difficult when it’s a small field, and this is a very small field.”

Genomic studies in 2005 have since shown that this co-receptor is found in insects ranging from mosquitoes to moths,  making humans invisible to insects. Using tissue cultures, she uses targeted drug discovery to screen 91,520 compounds from a chemical library, short-listing about 150 that she believes have the potential to be insect “confusants.”

Even Vosshall’s skeptics admit the confusant strategy is fundamentally sound. Zwiebel says his unpublished molecular work confirms the existence of confusants, but when it comes to DEET, he and Vosshall aren’t willing to budge. “We have agreed to disagree on the DEET story,” he says.

Resources

Smells funny? – Brendan Borrell  The Scientist.com Volume 23 | Issue 1 | Page 19.

http://www.the-scientist.com/2009/01/1/19/1/

Mosquitoes smell and avoid the insect repellent DEET – Leal and Zainulabeuddin Syed,  PNAS 105:13598-603, 2008 September 2008.


Image courtesy
of LJ Zwiebel, colorization by Dominic Doyle / Vanderbilt University

Ladybugs -Healthy plants have lots of helpers


ladybugThe University of Granada found that ladybugs are a useful way of distinguishing organic, conventional and integrated farming systems.The university said a two-year study of three large Spanish olive groves showed the “richness and abundance” of ladybugs was higher in organic orchards. Spanish researchers say ladybugs in olive orchards are a good indicator of the groves’ health and sustainability.
Ladybugs, also called lady beetles or ladybird beetles, are a very beneficial group. They are natural enemies of many insects, especially aphids and other sap feeders. A single lady beetle may eat as many as 5,000 aphids in its lifetime. There are many species of lady beetles.

Protection for the plants and the ladybugs

Adult lady beetles have very characteristic convex oval shaped bodies that can be yellow, pink, orange, red, or black, and usually are marked with distinct spots. This bold coloring, noxious fluid that seeps out of their joints when they are disturbed and strong odor they give off warns other animals to stay away. when the insects are disturbed.

ladybug eggs on leaf

Adult females will lay clusters of yellowish eggs on plants in the vicinity of aphid, scale, or mealybug colonies.

The alligator-like larvae (pictured below) are also predators. They are spiny and black with bright spots.

Adult lady beetles have very characteristic convex, hemispherical to oval shaped bodies that can be yellow, pink, orange, red, or black, and usually are marked with distinct spots. This is a type of warning coloration to discourage other animals that may try to eat them. Like many other brightly-colored insects,they are protected by an odorous, noxious fluid that seeps out of their joints when the insects are disturbed. The bright body coloration helps some predators to remember the encounter and avoid attacking insects with similar markings.

Ladybug larvae are helpful to humans because they eat the insect pests in the garden. After feeding on insect prey for several weeks, the larva pupates on a leaf.

ladybug larva feeding on aphids

Ladybug larva feeding on aphids

Some lady beetle species have several generations each year while others have only one. During the summer months, all stages can often be found at the same time. Adults of some species spend the winter clustered together in large groups under leaf litter, rocks, or other debris.

Resources

Ladybugs a sign of healthy olive trees - Staff Writers, Granada, Spain (UPI) January 7, 2009.
http://www.seeddaily.com/reports/Ladybugs_a_sign_of_healthy_olive_trees_999.html

LADYBUGS - Ric Bessin, Extension Entomologist University of Kentucky College of Agriculture
http://www.ca.uky.edu/entomology/entfacts/ef105.asp

Images courtesy of

Image 1: http://groups.wfu.edu/Phi-Mu/ladybug.JPG

Image 2 & 3: Ric Bessin, Extension Entomologist
University of Kentucky College of Agricultur

What other topics do you want to know more about? Let us know.

Fewer birds, frogs… increase toxins-thanks to shortsighted wetland management


shorbirdIn Bismarch, N.D. Federal wildlife officials are taking applications from farmers who want the government to remove cattail-infested wetlands, the preferred habitat of sunflower-snacking blackbirds.

Phil Mastrangelo, the state director for the U.S. Department of Agriculture’s Wildlife Services agency, said applications will be accepted from January until June.

More than 60,000 acres of cattail marshes in North Dakota have been destroyed since 1991, to try to keep blackbirds from attacking sunflower fields, he said. (This is a repeat ofc the Misissippi Delta mess and we wonder why our wildlife is decreasing!)

Cattail eradication leaves blackbirds without a place to nest or roost and makes them more vulnerable to predators, said Larry Kleingartner, executive director of the Bismarck-based National Sunflower Association.

“It has been the most effective tool we have in dealing with blackbirds,” he said.

Last year in North Dakota, about 3,700 acres of wetlands in seven counties were treated, Mastrangelo said. (Poisoning our native lands should never be allowed! -Short sighted)

A herbicide is applied in late summer from a helicopter, at a cost to the government of about $22 an acre, Mastrangelo said. The agency had hoped to treat double the amount of wetlands last year but the cost of the herbicide doubled, he said.

“The increased cost in herbicide reduced the amount of acres we could treat,” Mastrangelo said.

The amount of acres that will be treated this year is still unknown, he said.

“We won’t know for at least a couple of months if the herbicide stabilizes in price, goes up or hopefully goes down,” he said. (May the price go through the roof.)

Although the program targets only cattails on private land this herbicide kills lots more animals them anyone is willing to admit..

Kleingartner said blackbirds eat more than $20 million worth of sunflowers each year in North Dakota, which accounts for about half the nation’s sunflower production.

Some 70 million blackbirds come through the Northern Plains each year, including about 6 million that stop in North Dakota, biologists say. Each blackbird can eat about an ounce of sunflower seeds daily.

Cattails cover some 600,000 acres of wetlands in North Dakota. Mastrangelo said wetlands treated with the herbicide are typically free of cattails for about five years. (The pesticide will live on in the water and soils and run the risk of seeping into the water table and crops in the area.)

Noise cannons also are used to shoo blackbirds off sunflower fields.

Sometimes nothing works, so farmers have either quit growing the crop or planted in other areas, Kleingartner said.

“Some farmers have just found out that they can’t competitively produce the crop without blackbird damage,” he said.

Increased corn production in North Dakota has helped sunflower farmers some, Kleingartner said.

“Additional acres of corn have provided an additional feeding source,” Kleingartner said. “But definitely, blackbirds still prefer sunflowers to chew on.”

Stop this stupidity.

Resources

National Sunflower Association: http://www.sunflowernsa.com

USDA taking applications for Cattail eradication
– JAMES MacPHERSON, AP January 8, 2008.

http://news.yahoo.com/s/ap/20090108/ap_on_bi_ge/farm_scene_killing_cattails;_ylt=AogpeBnY_U7jWN4O6F4FLgwPLBIF

Wildlife Services: http://www.aphis.usda.gov/wildlife_damage/

Image courtesy of

image

Killer whales disappearing why?


Local Puget orcas numbers continue to decline. Seven orcas that regularly visit Puget Sound have died since November 2008 the biggest die-off in about 10 years.
One group of scientists will use a dog to help sniff out the answers and another will chase whales in speed boats and catch the water droplets from their blow holes for analysis and yet another will tag some pod members to see where they migrate to when not in the Puget Sound area. All trying to answer the question.

Why the die-off?keiko_bow

Some speculate the continued decrease in population is due to the decrease *chinook salmon a key food. Protecting Puget Sound equals saving salmon, which equals saving orcas. The southern resident population is down to 83 animals from 97 in 1996. The orcas were listed as an endangered species in November 2005

Both Northern Resident and Southern The Puget Sound whales are most PCB-contaminated mammals in the world. PCB effects an increase when food intake decreases, because the animal uses its fat reserves for energy during food supplies are low. This releases more PCBs into circulation, increasing toxins and their effects in the body. PCBs and other toxins come from human waste, agricultural pesticides and cosmetics, fluorescent lighting fixtures, electrical appliances containing PCB capacitors, old microscope oil, and hydraulic fluids, plastics, and oil slicks.
Due to the chemical properties of PCBs they concentrate up the food chain and collect in fatty tissues.

Since all the southern resident orcas have much higher PCB levels than northern residents, this may explain the drastic southern resident decline under comparable nutritional pressures. It would also suggest that efforts should strive to simultaneously address both toxin loads and prey abundance.

* Stress - University of Washington researchers who studied the orcas hormones and toxins from scat (poop) of the remaining 83 orcas have found signs suggesting the mammals may be starving, possibly due to dwindling salmon runs. UW researchers who use a 2-liter bottle on a telescoping pole to collect whale scat for analysis have found a link between whale mortality and low levels of thyroid hormone, which partly controls metabolism. When whale deaths are up, thyroid levels are down, suggesting that the whales are starving.When whales don’t eat much, they draw down their fat reserves, where toxins are stored, said Katherine Ayres, a graduate student doing work under Wasser. When that happens, toxins enter the circulation system and could cause health problems, she said.
* Poor Nutrition - When whales don’t eat much, they reabsorb their fat reserves, where toxins are stored, said Katherine Ayres, a graduate student doing work under Wasser. When that happens, toxins enter the circulation system and could cause health problems, she said. By collecting scat and analyze the fish scales and other remains the orcas leave behind after feeding, Hanson and others run it through a genetic database.

* Ocean pollutants such as oil, plastics, cosemetics, agriculture runoff and sewage
* Vessel noise disrupts the whale’s ability to find food or disease – four citations have been issued under a new state law designed to keep vessels farther away from whales. Among the offenders were two different Canada-based whale-watching operations ticketed for coming within 300 feet of the orcas, said Sgt. Russ Mullins with the state Department of Fish and Wildlife.

* Diseases - Another group scientists from Global Research and Rescue is riding alongside the whales (How much fun is that!), using petri dishes on poles will collect air droplets from the blowholes. The breath samples are being studied to determine potential diseases..

* Decrease in Chinook salmon - A study of the births and deaths of the whales will look for a correlation between births and deaths of orca with the salmon runs. If a positive correlation is found then conservations methods can be put in place to protect the orcas and insure a adequate fish supply.

Where do they go ? – Mystery surrounds the whale’s winter migration

The Center for Whale Research on San Juan Island plans to tag the dorsal fins of six of the southern resident population of killer whales to track where they go and what they eat. For the past seven years, two of the pods have been seen in central California, possibly looking farther for food the endangered salmon.

Policing the waters -protecting the orcas

So far four citations have been issued to vessels invading the orcas waters. Under a new state law vessels farther must stay at least 300 feet away from whales.

NOAA Fisheries is also writing new rules for vessels operating in federal waters.

Resources

Die-off of Puget orcas linked to lack of key food — salmon Tucson, Arizona October.26.2008

Center for Whale Research: http://www.whaleresearch.com/

National Marine Fisheries Service: http://www.nmfs.noaa.gov/

Global Research and Rescue: http://www.grrescue.org/

University of Washington Center for Conservation Biology: http://depts.washington.edu/conserv/
http://news.yahoo.com/s/ap/20081220/ap_on_sc/endangered_orcas;_ylt=An.y4_BpPrNdSGmmhoNSnvoPLBIF
PLBIF

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