Effect of temperature and termite starvation on phagocytosis by protozoan symbionts of the eastern subterranean termite Reticulitermes flavipes Kollar

摘要

Many termite species rely on intestinal protozoan symbionts to digest their cellulosic foods. Cellulose acquisition by the symbionts of the Eastern subterranean termite Reticulitermes flavipes was examined by following their phagocytosis of red paper fed to the termite host. The effects of termite host starvation and environmental temperature on feeding activity were studied in the zooflagellates Trichonympha agilis (Trichonymphidae), Pyrsonympha vertens, Dinenympha fimbriata, and D. gracilis (Pyrsonymphidae), which are among the largest residents in R. flavipes' hindguts. Protozoans in termites starved for 24 h ingested red paper significantly sooner than protozoans in termites with continuous access to food. Trichonympha, Pyrsonympha, and Dinenympha all ingested red paper particles at approximately the same rate. Red paper appeared significantly sooner in protozoans in termites maintained at 32deg C than in those maintained at 22deg C or 26deg C. At 32deg C, numbers of Trichonympha per gut remained constant over 96 h. Pyrsonympha and Dinenympha cells were absent or significantly reduced in number by 72 h at that temperature. These results provide insight into the environmental factors that shape the termite-protozoan symbiosis. They may aid in the development of protozoicides used to control pest termites.