Prey assemblages and inhabitant communities in pitchers were compared among 10NepenthesLinnaeus 1753 species with various pitcher morphologies in West Sumatra, Indonesia. There were significant differences in the number of prey organisms trapped per pitcher amongNepenthesspecies and among pitcher ages but no significant differences among localities nor between the vertical positions of pitchers. Prey assemblages of eightNepenthesspecies were predominated by ants.Nepenthes bongsoKorthals 1839 andN. albomarginataLobb 1849 had prey assemblages characterized by high frequencies of midges and termites, respectively. Pitchers captured prey organisms not by random trapping but by attracting specific groups of organisms.