Functional morphology and evolution of the hyper-elongated intromittent organ in Cassida leaf beetles (Coleoptera: Chrysomelidae: Cassidinae)

The peculiar phenomenon of hyper-elongation of intromittent organs is well known in a number of insect groups. However, the unresolved questions of how and why such a phenomenon originated independently many times continue to attract biologists' attention. To be able to detect the evolutionary driving mechanisms that enabled insects to repeatedly acquire such a peculiarity, first of all the structural key features and the mechanics of these...