We humans know the olfactory sense to be a very strong one. One whiff of the right perfume can whisk you back to your grandmother's living room; a hint of musty books can return you to the stacks of the college library. And, of course, smell tends to steer us away from bad things too. Lest we think our noses are so special, new research shows that insects also possess the ability to derive meaning from specific scents.
McMaster University professor of biology David Rollo and his team were studying the social behavior of cockroaches when they discovered that their subjects strictly avoided locations scented with an extract from fallen fellows. Turns out a combination of fatty acids present in the decaying husks of roaches and other insects, such as ants and caterpillars, as well as in pill bugs and woodlice—crustaceans which diverged from insects over 400 million years ago— is the chemical blend that creates a death stench that signals the living to stay away. Avoidance of areas where relatives have died raises the chance of evading disease or predators.
This primal intuition may not cause cockroaches to yearn for their youth, but it may explain how they're so good at staying alive.