bryophagy; consumption; detritophagy; feeding pattern; Orthoptera; Tetrigoidea; tropical zone

Groundhoppers (Tetrigidae) are a basal group of Caelifera that exhibit a conservative feeding strategy associated with the consumption of detritus and lower plants. We studied the feeding strategies and associated morphology of the mandibles of seven tropical groundhoppers from three different subfamilies occupying three different habitats in Borneo. We investigated (1) whether the feeding strategies and associated mandible structures of tropical species are more diverse than those of previously studied groundhoppers from temperate zones and (2) whether the feeding strategies of studied tropical species were more closely associated with subfamily membership or with occupied habitat. All the studied species displayed similar feeding patterns, with detritus being the main food component, followed by mosses and other particles (algae, invertebrates, fungal hyphae and mineral particles), and quantitative morphometric analysis of mandibular variability confirmed a partial association of their morphology with the occupied habitat. We found that phylogenetic relationships were less significant for the evolution of feeding patterns and mandibular morphology than were species-level habitat associations. Moran's phylogenetic autocorrelation coefficient did not confirm the association of feeding preference with subfamily affiliation. We confirmed that dietary pattern is strongly conserved in Tetrigidae but that the ratio of the main food components is influenced by the type of habitat occupied.