Trigonotylus uhleri, a true bug of the family Miridae, is an herbivore of Spartina spp., native to the Atlantic coast of North America from Massachusetts to Mississippi (Blatchley 1926, Cohen and Carlton 1995). It was discovered in in 1993, in several marshes dominated by introduced Spartina alterniflora (Smooth Cordgrass), transplanted for wetland restoration in the 1970s to South San Francisco Bay (Daehler and Strong 1995; Cohen and Carlton 1995). Densities were high for an insect of this size, averaging about 10 animals per culm of Spartina. This bug has not been found in other West Coast estuaries.
The photo is of the European species T. caelestalinum.