Fruit Flies Use Alcohol To Fight Parasites
February 17, 2012

Fruit Flies Use Alcohol To Fight Parasites

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According to new research, alcoholic beverages might just be a new form of medication to help fight off parasites.

Researchers reported in the February 16 edition of Current Biology that fruit flies will actually seek out alcohol to kill off blood-borne parasitic wasps living within them.

They said that the discovery offers some of the first evidence that alcoholic drinks may be useful in fighting infections.

"We found that environmental alcohol protects fruit flies from being parasitized by wasps, and that, even after being infected, fruit fly consumption of alcohol leads to death of the wasps growing within them," Todd Schlenke of Emory University said in a press release. "Surprisingly, fly larvae actively seek out ethanol-containing food when infected, showing they use alcohol as an antiwasp medicine."

They found that fruit flies have a tolerance for alcohol after generations of the species have fed on rotting and fermented fruit.

"D. melanogaster has a special ability to tolerate high levels of alcohol," Schlenke said in the press release. "It seemed possible that this ability might protect the flies from generalist parasites."

He said that parasites might even have helped push the flies toward an alcohol-drinking existence.

Wasp mothers lay their eggs in fruit fly larvae and eject venom to suppress their hosts immune response.

If the venom is effective enough, the wasp egg hatches, and the wasp larva begins to eat the fruit fly larva from the inside out.

The researchers wondered if the fruit flies could be using the toxic effects of alcohol in their natural habitat to fight off the wasps.

They used a bisected petri dish filled with the yeast that fruit flies are normally fed in a lab environment, and released fruit fly larvae into the dish.  On one side of the dish, the yeast was mixed with 6 percent alcohol, while the other side remained alcohol-free.

After 24 hours, 80 percent of the fruit fly larvae that were infected with wasps were on the alcohol side of the dish, while only 30 percent of the non-infected fruit fly larvae were on the alcohol side.

The infected fruit flies that consumed alcohol beat out the wasps in about 60 percent of the cases, compared to a 0 percent survival rate for fruit fly controls that fed on plain yeast.

As for the wasp born on the alcohol side of the dish, its " internal organs disperse and appear to be ejected out of its anus," Schlenke says. "It's an unusual phenotype that we haven't seen in our wasps before."

The researchers say that this study could be evidence that alcohol might have applications for the medical industry.

They said alcohol could be added to parasite culture in the lab to find out what sort of effect it might have.

"These little fruit flies, the same that hover around the brown bananas in your fruit bowl, are making complex decisions about how much alcohol to consume based on whether or not they have internal parasites," Schlenke said. "Who knows, maybe they can teach us something about how to fight off our own parasites."


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