PATHOBIOLOGY AND DISEASE TRANSMISSION IN DAMPWOOD TERMITES [ZOOTERMOPSIS-ANGUSTICOLLIS (ISOPTERA, TERMOPSIDAE)] INFECTED WITH THE FUNGUS METARHIZIUM-ANISOPLIAE (DEUTEROMYCOTINA, HYPOMYCETES)

The dampwood termite Zootermopsis angusticollis is susceptible to infe ction by the fungus Metarhizium anisopliae. Termites exposed to filter paper impregnated with one of several spore suspensions (7 x 10(7), 7 x 10(4), 7 x 10(1) and 7 x 10(-2) spores/ml) exhibited a dosage-depen dent mortality. LT,, estimates ranged from 2.7 days (7 x 10(7) spore/m l) to more than 10 days (7 x 10(-2) spores/ml and controls). Infected termites became lethargic and unresponsive to tactile stimulation, and in many instances developed abnormal pigmentation, perhaps as a resul t of melanin encapsulation. Interactions between infected termites (ex posed to a 7 x 10(7) spores/ml concentration) and healthy nestmates fa cilitated the transmission of disease to the healthy individuals. Path ogens may be important agents of selection, and disease may influence many of the biological attributes of termites, including the apparent high degrees of inbreeding. Focusing on the ecological and evolutionar y significance of disease and disease resistance mechanisms of termite s may provide a better understanding of the selective pressures that i nfluenced social organization, and the evolution and maintenance of in sect sociality.