Image of the Week - November 5, 2002

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Encapsulation of Parasitic Wasp Eggs

Three ESEM images of parasitic wasp (Cotesia flavipes) eggs, dissected from an unsuitable caterpillar host (Ostrinia nubilalis, the European corn borer). The top image, taken in 'wet' mode, is of an unencapsulated, normal egg, at 4 hours after parasitization. The middle and lower images, taken in 'hi-vac' mode, are of eggs at 8 hours following parasitization. The middle image shows two hemocytes (insect blood cells), the spherical bodies at either end of the egg. The bottom image is of an egg that has been completely encapsulated by hemocytes, which flatten against the egg once they have attached. Other, still spherical, hemocytes - more recent arrivals - are also visible in this image. Encapsulation by the host's immune system will kill the parasitic invaders.

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Uploaded Tue Nov 5 08:56:53 2002 by Scott Jay Robinson

Updated Tue Jan 26 22:40:27 2010 by Daniel E. Weber