Waving a Red Flag

Autumn leaves: warning signal to insect pests

  • NWF Staff
  • Oct 01, 2001

The flaming fall displays of sugar maples and other deciduous trees may have a function beyond luring tourists. Two British scientists believe that the spectacular red and yellow leaves are actually a warning signal to insect pests that typically attack the trees in autumn. The trees are essentially alerting the pests that they face a variety of countermeasures--from thickening leaves to chemical defenses--if they attack. The scientists base their hypothesis on their finding that the trees with the brightest displays are the most likely targets of sap-eating aphids. "In short," says Sam Brown, one of the experts, "they are pick on someone else' signals to specialist autumn-flying insects."

Get Involved

Where We Work

More than one-third of U.S. fish and wildlife species are at risk of extinction in the coming decades. We're on the ground in seven regions across the country, collaborating with 52 state and territory affiliates to reverse the crisis and ensure wildlife thrive.

Learn More
Regional Centers and Affiliates