They have 'ears' at the base of their front wings. When they hear bat echolocation sounds, they close their wings and drop down. They can escape spider webs, because, being so light, they do not create much vibration to alert the spider. Instead of struggling like most insects, the lacewing bites through the strands holding its legs and antennae. When it is stuck only by its wings, it become completely immobile. Slowly, the lacewing slides downwards out of the web. Tiny hairs on the wings prevent the sticky spider silk from touching the wings' surface. 