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Aphid Defense

August 1, 2007

Exploding aphids that foil predators.


The internal explosives of bugs. I’m Bob Hirshon and this is Science Update.

Did you ever secretly mix two chemicals in chemistry class to get an explosion of noxious fumes? Well, biologist Glen Powell of Imperial College London discovered that cabbage aphids do just that inside their bodies. One of the chemicals comes from the cabbage plant itself: the aphids eat it and store it in their blood. The aphids produce the other chemical themselves and store it in their muscles. If a predator ladybug takes a bite out of one of the aphids, the two chemicals meet and blast the ladybug with poison.

GLEN POWELL (Imperial College London):
The type of damage that needs to be done in order to mix the blood with the muscle tissue to actually produce this reaction is fairly extreme, so probably the aphid dies in the process.

But Powell says it dies a hero’s death, protecting its colony. I’m Bob Hirshon, for AAAS, the science society.