Fig 1.

Quantification of biofilm biomass of free-living and symbiotic (Euprymna and Sepiola) V. fischeri strains before grazing (gray bars) and after grazing (white bars) on early (R. nauta and N. designis) and late (T. pyriformis) biofilms. The optical densities were measured after solubilization of crystal violet, with the abundance of biofilm considered directly proportional to the optical density reading. Error bars represent the standard deviations. *, P < 0.05 for the difference between grazed and nongrazed bacteria; **, P < 0.01. The composite data are from 13 free-living strains, 8 Sepiola strains, and 12 Euprymna strains (see Table 1).