Stridulaton in leaf beetles (Coleoptera, Chrysomelidae)

The morphology of all known stridulatory organs of the Chrysomelidae is described. Bioacoustic data are reviewed and phylogenetic considerations are outlined. All stridulatory devices of Chrysomelidae consist of a pars stridens made up of a number of parallel cuticular ribs, and a plectrum which is either formed by a single cuticular ridge (Zeugophorinae, Megalopodinae, Hispinae and Cassidinae) or a patch of uniform cuticular denticles (Criocerinae). Three types of stridulatory organs have been de- scribed in the literature: mesoscuto-pronotal (Zeugophorinae, Megalopodinae, Clytrinae), abdomino-elytral (Crio-cerinae) and vertico-pronotal (Hispinae and Cassidinae).

Those Chrysomelidae possessing a mesoscuto-pronotal organ are probably more closely related to certain Cerambycidae. The particular abdominoelytral organ of the Criocerinae is a synapo- morphy of the taxa belonging to that subfamily. The pars stridens was primarily composed of two medially separated fields of parallel ribs on the 8th abdominal tergite. In the course of evolution these fields fused into a single file. The vertico-pronotal device of Hispinae and Cassidinae is probably a primary feature of these two subfamilies which must have been reduced several times during their evolution.