Distribution and relative abundance of three protist genera within the Zootermopsis nevadensis nuttingi hindgut

The termite Zootermopsis nevadensis nuttingi, which inhabits coastal forests of the western United States, plays an important ecological role in the breakdown and digestion of wood. Vital to this role are symbiotic protists residing in the termite’s hindgut. Five protist genera of varying size and morphology make up this gut community, but very little is known about their spatial organization within the hindgut or the number of protist cells per host. To resolve this issue, we used light microscopy and a hemocytometer to determine the distribution of the larger protist genera across hindgut segments. We found that Streblomastix were the most abundant cells in all three segments, but especially in the anterior hindgut. Trichomitopsis cells were significantly more abundant in the posterior hindgut. Trichonympha were the least abundant overall, often reaching their highest abundance in the middle segment but with a more variable distribution. Understanding the distribution of different protists within the hindgut may improve our understanding of the ecological relationships among protists, as well as their individual roles in lignocellulose digestion, contributing to a better understanding of the symbiotic system as a whole.