Presidential Politics Meet Parasites!

By Carl Zimmer | October 27, 2008 3:31 pm

psyttalia.jpgI’ve been quietly watching scientists flip out about Sarah Palin’s recent scoff about the US funding research on fruit flies in Paris–even Christopher Hitchens is now championing those fine insects today in Slate. But, thanks to a little grant-digging by PZ Myers, I discover that, in fact, all this brouhaha comes down to those dear friends of this blog, parasites. Frankly, if you wait long enough, everything comes down to parasites.

A lot of people thought at first that Palin was dismissing basic research on Drosophila melanogaster, which has yielded lots of profound insights about human biology. Palin herself hasn’t cleared up the issue, but on further reflection, the consensus is that she was complaining about research on the olive fruit fly. That insect is a nasty crop pest in the US. It’s also a pest in Europe, where people have been studying ways to control it–hence the need for funding research there.

So–how do they plan to control these pests? By unleashing a vicious, brutal death on their babies! (Apologies to any insect-rights people out there…)

Pests often become pests by getting shipped to new places where they can thrive without all the parasites and pathogens that kept them in check back home. So a promising way to rein them in is to go back to where they were evolved, and find some really nasty parasites that evolved with them. Happily, scientists have found a wasp in Africa, where the olive fruit flies came from, that appears to be specialized to lay their eggs only in the larvae of the flies. The wasps then drink up the larvae’s bodily fluids and crawl out, leaving behind the dried up corpse of their host. So the scientists have shipped the wasps to California and done a lot of testing on the them (you have to make sure they won’t go off and start killing harmless native insects). Their goal is to shower the wasps across the olive fields of America.

This may seem outlandish, but it’s actually a fairly well-developed technique for controlling pests. In my book Parasite Rex, I describe a devastating outbreak that threatened Africa’s cassava plant–a staple for millions of people across the continent. The cassava were being wiped out by mealybugs from South America. In the late 1980s, entomologist Hans Herren and his colleagues found a South American wasp and brought it to Nigeria. Then he had to figure out how to get the wasps to their hosts.

The wasps were put to sleep with carbon dioxide and then lodged in cylinders of foam rubber, 250 in each one, which were loaded into a magazine that had been custom-built for Herren at an Austrian camera factory. As the pilot passed over a field, Herren intended for him to be able to drop the wasps precisely. “It was like in fighter aircrafts. You know when to drop the bomb by looking at the crosshairs. We tried this over a swimming pool in Ibadan. We’d fly over and drop the wasps. At 180 miles per hour, we were able to get them in there.”

Once Herren figured out how to drop his parasitic payload precisely, he started showing millions of wasps on African farms. After a few years, Herren had driven down the mealybugs to tiny numbers.

So please, my fellow Americans, think kindly on parasites this election year. If handled right, they can save your dinner.

[Image Source]


Comments (7)

  1. Scott Belyea

    Fascinating stuff. When Palin next reads your blog, I’m sure she’ll realize the error of her ways.

    “…if you wait long enough, everything comes down to parasites.”

    Odd … all these years, I thought it was turtles …

  2. The parasites stand on the back of a turtle, and then it’s turtles all the way down. 😉

  3. Mus

    “When Palin next reads your blog, I’m sure she’ll realize the error of her ways.”

    OMG, she can read?!!!

  4. The wasps then drink up the larvae’s bodily fluids and crawl out, leaving behind the dried up corpse of their host.

    I think you meant the larvae drink up the fly’s fluids, no?

    I saw PZ’s excellent detective work on this. I was disappointed a little because on, Richard Dawkins coined the word “Drosophilistinism.” It made me happy. 😀

  5. David B. Benson

    Wow! The bottled green stuffed olives I buy are from Spain and Agentina.

    Do some bombing there, too.

  6. Jen

    Yes. And the olive fruit fly ONLY attacks Olive Trees. And the EARMARK–outside of millions already spent on OLFF control in California–was given as a POLITICAL favor to Thompson’s donor community. There are already very effective methods of Organic Pest control available to Olive growers. If they want the addition of African wasps–they can pay for it themselves. They’ve got the money.It’s not like eliminating $50.00 a gallon artisan crafted olive oil from the American food supply is going to cause widespresd hunger.

    You can try to spin this sick little episode of Palin bashing all you like.

    The fact is that PZ Myers, Hitchens and the rest have spread a hateful disinformation campaign with false information. It had not a damned thing to do with Drosophila. They just–in a very unscientific manner–assumed that it did. TO any rational, honest, thinking person–they are the ones who look “anti-science” because they are promoting the awarding of funding based not on merit–but on a congressman’s donor list.


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The Loom

A blog about life, past and future. Written by DISCOVER contributing editor and columnist Carl Zimmer.

About Carl Zimmer

Carl Zimmer writes about science regularly for The New York Times and magazines such as DISCOVER, which also hosts his blog, The LoomHe is the author of 12 books, the most recent of which is Science Ink: Tattoos of the Science Obsessed.


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