Nitrogen sources for neotropical nasute termites: Fixation and selective foraging.

Studies with Nasutitermes and Rhynchotermes (Isoptera, Nasutitermitinae) in a Costa Rican rainforest suggest that nitrogen fixation by gut symbionts may play a significant role in termite nutrition. Leaf-litter feeders ingest more and fix less nitrogen than do wood-litter feeders; both species feed preferentially on N-rich foods in their foraging repertoire. Unusually high N2 fixation (acetylene reduction) rates were found in Nasutitermes soldiers, thereby reducing their nutritional dependence on workers. Finally, N2 fixation rates of termites diminished rapidly within 24 h after removal of a colony from the field, underlining the importance of conducting future N2 fixation studies under field conditions.