FUNCTIONAL-MORPHOLOGY AS AN AID IN DETERMINING TROPHIC BEHAVIOR - THEPLACEMENT OF ASTIGMATIC MITES IN FOOD WEBS OF WATER-FILLED TREE-HOLE COMMUNITIES

The arthropod communities of phytotelmata (plant-held waters) are cons idered excellent subjects for studying and testing community theory. F ood webs constructed for phytotelm communities, however, usually exclu de mites or determine their placement based on little, if any, actual knowledge of their trophic behaviour. Although individually small, man y acarine species attain high population levels and therefore may be i mportant as prey for other inhabitants, as processing chain species in commensal relationships and as competitors of the larger tree-hole in habitants. An understanding of the trophic relationships of acarine in habitants is therefore essential to an understanding of the dynamics o f phytotelm communities. Studies emphasizing the functional morphology of mouth parts of astigmatic species inhabiting water-filled tree hol es in the eastern USA and in Queensland, Australia, reveal a diversity of trophic groups. Among these are 'shredders' who ingest leaf materi al and associated microbes by biting off chunks of leaves, 'scrapers' (= grazers) who crop fungal hyphae and/or other microbes and detritus from the substrate surface and 'collectors' who filter microbes and fi ne particulate matter from the water. This information allows for the more exact placement of acarine inhabitants in food webs of water-fill ed tree holes. Exp Appl Acarol 22. 435-453 (C) 1998 Kluwer Academic Pu blishers.