Fig. 2.

Buchnera haplotype frequencies within individual mothers and daughters, over five generations. (A) Frequencies starting with a single female heteroplasmic for Buchnera haplotypes 5AY and LSR1. (B) Frequencies in aphids starting with a single female heteroplasmic for Buchnera haplotypes 5A and LSR1. (A and B, Right) Lines kept at constant 20 °C (“Cool” treatment), and (Left) lines subjected daily to 4 h at 33 °C (“Heat” treatment). Lines connect the mother–daughter pairs and are colored to enable visualization of individual matrilines within experiments. For Generations 0 to 3, each mother produced three sampled daughters, each of which became mothers for the next generation. Generation 4 mothers each produced two daughters, and Generation 5 was the last one sampled. In some cases, an aphid died, ending that subline prematurely. The overall death rate was 8.0%.