State of colonization of juvenile squid encountering two strains presented sequentially. Squids were inoculated with strain D2 or S2 at time zero (t0), and strains D1 or S1 were added into the surrounding water at different times (t, in hours; X-axis). The percentage of squids either co-colonized (gray), or colonized only by the strain added either initially (white) or later (black), were determined. Between 29 and 38 animals were analyzed in three replicates. The graph represents the mean percentages for each result, and the error bars the 95% confidence interval