FIG 7.

Model for intraspecific competition during initial colonization of the E. scolopes light organ. The cartoon shows the six crypts (indicated by Roman numerals) of a juvenile light organ cocolonized with FQ-A001 (yellow) and ES114 (blue). FQ-A001-ES114 symbiont diversity can arise in the nascent light organ only through colonization of distinct crypts. Multiple cells of the same type can serve as founder cells for the resulting populations, e.g., FQ-A001 cells 1 and 2 or ES114 cells 2 and 3. FQ-A001 outcompetes ES114 during crypt colonization, which leads to a higher abundance of FQ-A001 than of ES114 in whole animals. (ES114 cells 4 and 5 fail to colonize.)