AVOIDANCE-BEHAVIOR IN GREEN LACEWINGS .1. BEHAVIOR OF FREE FLYING GREEN LACEWINGS TO HUNTING BATS AND ULTRASOUND

1. Free flying green lacewings (Chrysopa carnea) fold their wings and nose dive in response to cries of hunting bats. This is an early warning response that tends to take the insect out of the bat's acoustic field (Fig. 1). 2. However, should a bat detect and attempt to catch a falling green lacewing, the insect can switch to a last chance maneuver. This maneuver consists of a momentary extension of the wings, or wing flip, released by the bat's high cry repetition rate during the buzz, which is always associated with an attempted catch (Fig. 2). The last chance response can also be released by using artificial bat cries (Fig. 3). 3. The green lacewing's behavioral repertoire is not limited to early warning and last chance responses. The insects can change their pattern of flight or fall with the wings extended. The release of avoidance behavior depends upon the intensity and repetition rate of the ultrasonic stimulus (Fig. 4). 4. The responses of a single insect can vary for the same stimulus repeated successively. Avoidance behavior and variability are discussed in relation to selective advantage and to the interpretation of physiological results. © 1979 Springer-Verlag.