SMELLY chemicals released by plants seem to act as a warning to their insect predators.
Kaori Shiojiri and colleagues at Kyoto University in Japan have shown that corn plants release a volatile chemical when they are being eaten during the daytime. The scents attract predatory wasps that parasitise the caterpillars that feed on the plants. However, the caterpillars seem to be able to use the signals to predict the presence of wasps (Public Library of Science Biology, DOI: 10.1371/journal.pbio.0040164).
By exposing caterpillars to plant scents in both light and darkness, the researchers found that when the higher daytime scent…
