BOB HIRSHON (host):
Is love useful? I’m Bob Hirshon and this is Science Update.
We often hear that mates pair up based on fitness, to have the strongest offspring. But what about love? In the journal PLOS Biology, Malika Ihle and her colleagues at the Max Planck Institute report letting zebra finches choose mates from a large group. They let some of the pairs stay together; others were separated and assigned partners chosen by other finches. Ihle says those assigned pairs were much less successful in raising their young.
MALIKA IHLE (Max Planck Institute for Ornithology):
In fact, if a chick hatched in such a nest, it only had a fifty percent chance of surviving.
She says the birds that chose each other were more diligent in chick-rearing and were less prone to infidelity. Ihle concludes that beyond general fitness, birds pair up successfully based on what she terms “idiosyncratic sensory biases,” or what others might term “love.” I’m Bob Hirshon, for AAAS, the science society.