Bees Reveal the Buzz on Smell
Studies of bee brains are helping scientists unravel the mysteries of how animals smell, suggesting genetics play a key role in the detection of odors.
Neurobiologist Giovanni Galizia of the Freie Universitaet in Berlin and colleagues found that different odors trigger activity in different combinations of nerve cells in the brains of bees.
And since these combinations are nearly identical among individual bees, Galizia believes genetics are crucial in setting up this code. Their findings appear in the latest journal Nature Neuroscience.
Scientists have long known that most animals, including humans, detect smells when the nerve cells in their noses -- or antennae -- relay signals to grape-like clusters of cells in the brain, called glomeruli. Each odor activates a particular set of glomeruli, such that different odors are represented by different combinations of glomerular activity.
But exactly how this system is set up remained uncertain. If experience were important, scientists reasoned, then individuals should have different codes depending on their life histories. If the genes were the main determinant, however, then closely related individuals should share similar codes.
Studies in mammals and fish suggested that the latter was true, but the complexity of their brains limited scientists' ability to say for sure.
So Galizia and colleagues turned to the simpler brains of bees. "What's special in the bee is that you can recognize and identify the single glomeruli," says Galizia. "You can see that, for example, one is triangular, one is round, one is very big, and one is small."
Galizia and colleagues made a small opening in the heads of bees to monitor the activity of their glomeruli while they puffed odors onto their antennae.
To see the activity, they bathed the brains in a dye that seeps into nerve cells and brightens each time the cells become active.
The patterns of activity they observed were almost identical between bees, supporting the notion that genetics play a key role in determining the code. The scientists believe their data are also likely to apply to most other animals, where it is harder to obtain such clear-cut results.
"This is what has been predicted," says neurobiologist Albert Farbman of Northwestern University. "But it's nice to see it demonstrated. It's nice to see it's real."
By Marina Chicurel, Discovery Online News
Monarchs at Risk From Mexican Logging
Illegal logging is endangering the monarch butterfly, which winters in Mexico after migrating yearly from Canada and the United States, an environmental group says.
Environmentalists fear the loss of the forests will hurt the butterflies, which rely on oyamel pines west of Mexico City to spend the winter and breed.
The oyamel forests are owned by dozens of impoverished and overcrowded rural communities, which cut the trees for firewood, lumber or to clear the land for farming.
Mexico, Canada and the United States have tried to cooperate in protecting the butterflies, whose unusual migration has attracted the interest of experts and science projects by schoolchildren across North America.
But Mexico's environmental Group of 100 said Sunday the two northern governments had not done enough.
According to the group, recent surveys by the federal environmental prosecutor's office showed that four out of 10 communities in the region had cut twice the amount of wood authorized. The six other communities surveyed also had cut more wood than allowed.
The government has tried to limit cutting to a sustainable level, but illegal woodcutting persists. Enforcement is often left to state police agencies, which have been chronically corrupt.
Homero Aridjis, leader of the Group of 100, suggests that the governments or environmentalists buy the reserves to protect the butterflies. Similar plans have been criticized by those who fear they would leave the communities with too little land or force them to relocate.
Killer Bees Claim Two Lives in Argentina
Africanized "killer" bees stung a mother and her daughter to death in northern Argentina during a violent attack over the weekend.
Four other family members were taken to a hospital after they were stung by the bees in an elementary school near the tourist town of Rio Hondo, in the northern province of Santiago del Estero. Survivors escaped by throwing water at the insects.
The African bee arrived in the Western Hemisphere in the 1950s, when Brazilian geneticists decided the tropical bees might be better suited for South America's tropical climate than European honey bees.
African bees were released from the breeding program before selection was
completed. The bees have spread across the Americas at a remarkable 300 miles
(480 km) per year ever since.
Killer Bees Swarm Somalia
NA swarm of honey bees has killed seven people in southern Somalia, local authorities reported on Tuesday.
The bees attacked their victims as they were searching for food for their
livestock near the village of Tikhsile, located 25 miles (40 km) west of
the capital Mogadishu. The victims included three children, their mother
and three other adults.
Dogs Believed Killed by Killer Bees
Authorities in Boulder City, Nev., suspect killer bees are responsible for the death of one dog and the multiple stinging of another in their owner's backyard. Each dog was stung more than 100 times on Saturday.
State agriculture officials are studying some bees captured in the area to determine if they are the aggressive Africanized variety. Swarms of killer bees were found in nearby Pahrump earlier this year and may have migrated across the Nevada Desert to Boulder City.
The so-called killer bees have killed more than 1,000 people across Latin America since a colony escaped from a laboratory in Brazil in 1956. They appear to have reached their northernmost ability to migrate since they arrived along the U.S.-Mexico border region from California to Texas.
Madagascar Grasshopper Swarms
Update: The infestation of grasshoppers that has devoured a large portion of Madagascar's crops during recent months spread into the capital city of Antananarivo on Monday. A swarm at least 7 miles (11 km) long flew into the capital of the Malagasy Republic, prompting the government to set up a crisis center to deal with the worst insect plague in 50 years. Farmers in the central highland continued to struggle to protect their rice and other crops from the massive invasion.
Authorities asked the public not to ignite fires in the bush as a way to combat the swarms, but rather to find places where the insects sleep so that the areas can be targeted for aerial insecticide spraying.
Invading Ants Kill Texas Trout
An estimated 22,000 trout died in Texas' Guadalupe River last week after eating dead fire ants that fell into the waterway after mating in the sky. Some of the trout had ingested as many as 500 of the toxic insects, according to Texas Parks and Wildlife Department officials.
Trout kills of lesser magnitude occur on the Guadalupe every May, when tens of thousands of the winged ants embark on mating flights after the first heavy rain of the month. Males die, fall to the ground and roll into the river, where they are eaten by hungry trout. Females survive the mating ritual, land and start new colonies.
Fire ants migrated from South America, reaching the southern United States
during the 1930s. They can inflict painful and sometimes deadly stings on
humans and animals.
One of the more bizarre effects of the ongoing El Niño ocean warming phenomenon is a sudden invasion of grasshoppers in parts of western Arizona and southern Nevada. Swarms of pale-wing grasshoppers thrived in this year's moist and mild winter along the lower reaches of the Colorado River. Millions of them have descended on the cities of Laughlin, Nevada, and Lake Havasu City, Arizona, causing traffic accidents when motorists slid across insect-covered roads.
Street sweepers were dispatched to vacuum up masses of the hoppers and to haul them off to a landfill. Officials believe the insects will be swarming over the area until midsummer.
P.S. A visitor to Planet Insect wrote: . I'm in south central Texas and before I come in the house, I have to brush off my body and stomp my feet. I feel like I've got a breeding farm that's gone nuts!
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