Research has found an example of extreme reductive evolution in the symbiotic relationships between certain insects and bacteria. The discovery involves a record-breaking small non-organelle genome in symbiotic bacteria found in planthoppers, although similar symbiotic relationships have also been studied in other insects, including cicadas and xylophagous beetles. The specifics of these symbioses vary, with some involving nested symbiosis and endosymbiont replacement, and others involving dual bacterial symbiosis for cuticle supplementation and nitrogen recycling.