13. Parasitized Ants Get Berry Sick A nematode parasite causes ants to look like berries that birds like, putting ants on the diet and helping to spread the parasite. Cynthia Graber reports. ------------ When is an ant like a piece of fruit? When it’s infected by a parasite. Researchers affiliated with the Smithsonian Tropical Research Institute discovered this bizarre occurrence in Central America as they were studying the gliding ability of a certain species of ant. They found some colony members with bright red swollen abdomens. The scientists took specimens back to the lab and discovered they were full of hundreds of nematode eggs. The bright red bellies look suspiciously like the brilliant red and pink berries that proliferate in the rainforest. Researchers think that the nematode makes the ant look like fruit to get birds to eat the ants. Birds usually keep the ants off their menu because of armor and a bad chemical taste. The birds then spread parasite eggs in their droppings. Ants forage through bird droppings for seeds. They feed the infected droppings to ant larvae, beginning the infection process all over again. The red-bellied ant is the first known case of a parasite causing fruit mimicry. One of the researchers was surprised that something “dumb as a nematode” can manipulate its host in such a sophisticated way. But evolution works no matter how dumb organisms are. --Cynthia Graber
13.Parasitized Ants Get Berry Sick A nematode parasite causes ants to look like berries that birds like, putting ants on the diet and helping to spread the parasite. Cynthia Graber reports. ----------- (Whenis the ant like a piece of fruit, (when it's infected by) a parasite. Researchers affiliated with (Smithsonian Tropical Research Institute) discoverred that bizarre occurrence in central America as they (were) studying the gliding ability of certain species of ant. They found some (colony) members with bright red (swollen abdomens 腹部鼓胀). The scientists took (specimens)back to the lab and discovered they were full of hundreds of nematode eggs. The bright red (bellies腹部) look suspiciously like the brillion red(and)pink (berries) that proliferate in (the rainforest).
Researchers think that the(nematode) makes the ant (looklike a fruit (to get)birds(to) eat the ants. Birds usually keeps the ants off their menu. Because (of armor盔甲 and a bad) chemical taste. The birds then spread parasite eggs in(their)dropping. Ants (forage) through(bird) dropping for seeds. They feed (the infected) droppings to (ant larvae), beginning (the infection)process the all over again. The (red-bellied)ant is the first known case of parasite causing fruit mimicry. One of the researcher was surprised that something(dumb)as nematode" can manipulated its host in such sophisticated way. But evolution works no matter how (dumb) organisms are.
14. Electric Gold The lure of gold can be electric to some people, even though the element is chemically inert—on the large scale. But researchers from Georgia Tech report that, down at the level of atoms, gold can conduct electricity and act as an insulator as well. When an oxygen molecule is embedded into six atom-long gold wire, the wire can conduct electricity. But, when the wire is longer than six atoms, the oxygenated gold becomes an insulator. The scientists reported their discovery in the journal Physical Review Letters. The researchers say these properties mean that gold nanowires might be used as sensors to detect motion in nanoscale situations such as neurons or nanomachines (futuristic devices built from individual atoms that might enter cells and fight disease). The wire could be a sensor because when it’s extended even slightly, it could switch from a conductor to an insulator. Using gold as a sensor in this way could never have been predicted from what is known about gold in bulk. But being very small can lead to some big changes. —Steve Mirsky, with reporting by Harvey Black
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发表于 2011-10-15 21:50:52
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