Plant galls (cecidia) in the neotropical water plant family Podostemaceae induced by larvae of Chironomidae (Diptera)

Abstract

Novel kinds of plant galls (cecidia) induced in aquatic angiospermous macrophytes by larvae of non-biting midges are reported on for the first time, based on observations involving four species of the neotropical flowering water plant family Podostemaceae. The plants inhabit rocks in waterfalls and cascades and provide unique biocenoses in otherwise inanimate, dangerous environments. Assemblages of invertebrates populating the surfaces of the plants are dominated by larvae of Chironomidae. In addition, several species from the same insect family are found exclusively in leaf cavities surrounded by tissues and structures otherwise unseen on the respective host plants. This study reports on the morphological and histological modifications observed on such galls in Podostemaceae, and discusses some aspects of the plants' interactions with gall inducing chironomids.