Evolutionary dynamics of insect symbiont associations.

Bacterial symbionts of insects are pervasive and influence several ecologically relevant traits of their hosts. Although there has been rapid progress in understanding the extent and phenotypic outcome of these associations, there is a paucity of empirical data on fine-scale evolutionary processes that operate between the genomes of host and symbiont. Recently published papers examining symbiont relationships of aphids, fruit flies and butterflies are starting to reveal that these associations might be more dynamic than was appreciated previously.