Scanning electron micrographs of Oryzophagus oryzae (Coleoptera, Curculionidae), plastron structure and swimming behavior

Abstract

The morphological structures that permit Oryzophagus oryzae aquatic activities and swimming behavior were studied and compared with various weevils and other relevant species. The use of scanning electron microscopy facilitated the recognition of three different hydrofuge scales and sensilla. Based on the microscopic observations of behavior, morphological evidence, and comparisons with other curculionid species, it was supported that the gas exchange in O. oryzae adults relies on a subelytral air store maintained by hydrofuge scales and a ribbed margin on the adult elytra. The plastron structure is identical to Lissorhoptrus oryzophilus supporting the application of similar control measures for both species.