Science Update - Extreme Family Survival

22 July 2007

Interview with 

Bob Hirshon and Chelsea Wald, AAAS


A ladybird


Bob -   This week for The Naked Scientists we're going to talk about the lengths to which plants and insects will go to help their kin survive. I'm going to talk about some family-oriented plants called sea rockets, but first Chelsea tells us about a surprising ability of a common garden pest.

Chelsea -   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 in their bodies. One of the chemicals comes from the cabbage plant itself: the aphids eat it and store it in their blood. The other chemical the aphids make and store in their muscles. If a predator ladybird (ladybug) takes a bite out of one of the aphids, the two chemicals meet and blast the ladybird with poison.

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

Chelsea -   But Powell says it dies a hero's death, protecting its colony.

Bob -   Thanks, Chelsea. Some plants not only recognize their family members: they even treat them more generously than they treat strangers.  Plant ecologists Susan Dudley and Amanda File, of McMaster University in Canada, discovered this among plants called sea rockets.  Normally, when unrelated sea rockets are potted together, they grow longer roots than they would on their own - to better compete for limited water and nutrients.  But Dudley says things were different when they potted the plants with their siblings.

Susan Dudley (McMaster University, Canada):  The siblings basically didn't respond to sharing the pots.  So they didn't make this competitive response, while the strangers did.

Bob -   Since some other plants might share this behavior, Dudley says gardeners may get better results by planting crops near family. 

Chelsea -   Thanks, Bob. We'll be back next time with more amazing science from the country of family values. Until then, I'm Chelsea Wald...

Bob -   ...and I'm Bob Hirshon, for AAAS, The Science Society. Back to you, Naked Scientists...


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