Elastic joints in dermapteran hind wings: materials and wing folding

Representatives of Dermaptera probably have the most unusual hind wing vena tion and folding pattern among insects. Both correlate with unusual wing fo lding mechanics, in which folding is achieved from within the wing and unfo lding is done by the cerci. In this account, the hind wings of the earwig F orficula auricularia were studied by means of bright field and fluorescence microscopy. Resilin, a rubber-like protein, was revealed in several, clear ly defined patches. It occurs dorsally in the radiating veins, but ventrall y in the intercalary vein. This distribution determines the folding directi on, and resilin is the major driving mechanism for wing folding. Resilin st ores elastic energy in broadened vein patches and along the folds. At the o ther locations, the mid-wing mechanism and central area, the primary functi on of resilin is suggested to be prevention of material failure. The arrang ement of resilin patches is such that the wing cannot be unfolded from the thorax proper but must be unfolded by the cerci. In Dermaptera, the antagon istic movements of folding and unfolding are achieved in two different ways , resilin and cerci. To our knowledge this is unique. (C) 2000 Elsevier Sci ence Ltd. All rights reserved.