Figure 2

Cumulative offspring between days 2 and 6 of aphids differing in symbiont status when exposed to a bacterial challenge, sterile stab or handled as a control (experiment 1b). Cumulative offspring between days 2 and 6 $\left(\overline{X}\pm \text{ SE}\right)$ for aphids from the 5A clonal line with Hamiltonella defensa, Regiella insecticola, Serratia symbiotica symbiotic infection or no secondary symbiont (No symbiont) challenged with a heat-killed bacteria or a sterile stab, or that were handled as a control. Fecundity differed significantly depending on the symbiont status, and the conditions to which aphids were exposed. Symbiont effects were similar immediately after challenge and exposure did not influence reproduction on the first day after challenge so these data are not shown.