Evolutionary hypothesis of the symbiotic traits in the Burkholderiaceae. Abilities for initiation, accommodation, and cooperation in the bean bug gut have evolved in the common ancestor of the genera Pandoraea and Burkholderia (black box in the dendrogram), and only the competitiveness in the gut symbiotic organ has evolved in the SBE lineage (blue box in the dendrogram). These traits, except the initiation ability, are lost in BCC&P (white box in the dendrogram).