Figure 3.

Potential trade-offs with pathogen facilitation and protection in symbiont fitness and replication. (a) Covariation between competitive fitness of symbionts in haemocoel (without pathogen) and mortality risk during pathogen challenge. As above, mortality risk is represented as the instantaneous hazard parameter estimates from survivorship analyses. Labels indicate lineages that have evolved significantly different fitness from the ancestor; lineage D4 was the only strain to increase competitive fitness (post hoc comparison t = 2.836, p = 0.0051). (b) Treatment level means for competitive fitness relative to the ancestor. (c) Pathogen facilitation (mortality risk) trades off against an exponential growth rate of E. cloacae in vitro. Labels indicate lineages that have evolved growth rates significantly different than the ancestor (post hoc tests: L4 t = −2.03, p = 0.044; D4 t = −3.04, p = 0.003, D1 t = 9.58, p < 0.001). (d) Treatment level means for live and dead passage lineages (N = 6) relative to the ancestor. Ancestor data points are coloured black, dead passage lineages are orange/red and live passaged lineages light blue throughout. Centroids are means (±s.e.) for both x- and y-axes.