Figure 1

Cumulative offspring between days 2 and 6 of aphids from multiple clonal lines, without facultative symbionts, when exposed to a bacterial challenge, sterile stab or handled as a control (experiment 1a). Cumulative offspring between days 2 and 6 $\left(\overline{X}\pm \text{ SE}\right)$ of aphids challenged with a bacterial stab, sterile stab, or handled as a control pooling four aphid lines without secondary symbionts. Groups with different letters are significantly different from one another based on Tukey's HSD test. Exposure did not alter reproduction immediately after challenge so is not presented.