Monday, September 25, 2006

The Screwfly Solution

screwworm fly I thought I would kick off the blog with the Nebula award-winning novelette, "The Screwfly Solution", by "Racoona Sheldon"*. I don't want to spoil the plot, but I will talk a bit about the biology.

The screwworm fly (Cochliomyia hominivorax) is a pest that lives on live mammals and birds, causing severe losses in both livestock and wildlife. The eradication of the screwworm fly has been called "one of the greatest success stories in the history of agriculture in the Americas." Destroying the screwworm fly did not involve spraying with pesticides or other chemicals. Instead, the population was controlled by releasing large numbers of sterile male flies into the wild population. The females would still lay eggs, but they would not hatch, stopping the spread of the pest.

screwwormThis method required several biological advances:
• An understanding of the reproductive cycle and mating patterns of the screwworm fly
• A method for raising large numbers of flies in the lab
• The theory, put forth by Edward Knipling, that the fly population could be controlled by releasing sterile males
• A method for sterilizing male flies by irradiating them, developed during WWII

This "sterile insect technique" was very successful, and the USDA declared the United States free of indigenous screwworms in 1966. Eradication programs moved south, to Mexico in the 1970s, and continue in Central America through the present.

How did Sheldon weave this biology into her story? Read "The Screwfly Solution" for free at and find out!

For more information (and icky pictures and video of screwworm larvae-infested wounds), see the National Agricultural Library's Screwworm eradication collection .

* Racoona Sheldon is one of the pen names of Alice Sheldon, who usually published as James Tiptree, Jr. A recent biography (and accompanying website) describes her fascinating and somewhat tragic life.

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1 comment:

  1. Anonymous10:38 AM

    wow! thanks for pointing me to this story! :)


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