Evolution and Systematics
The nutrient-poor diet of cicadas is supplemented thanks to specialized bacterial symbionts.
"In collaboration with his post-doctoral research advisor Nancy Moran — who has NSF support to study insects — McCutcheon began observing the relationship between cicadas and the symbiotic bacteria that live inside them…
"'Certain cicada species occur in overwhelming numbers,' he says. 'And they are estimated to the most abundant herbivores in terms of both their total weight and the total number of individuals in some North American forests.'
"But even more amazingly, cicadas achieve such success despite their reliance on a nutrient-poor diet. Most species of cicada spend most of their lives (from two to 17 years) underground before emerging en masse at regular intervals. While underground, cicadas feed solely on the sap of plant roots, which is the most nutrient-poor and unbalanced part of plants.
"So how do cicadas gather the nutrients they need to survive, despite their low-nutrient diet? McCutcheon says that cicadas supplement their diet by maintaining complicated relationships with two species of specialized bacteria [Sulcia muelleri and Hodgkinia cicadicola] that live inside their cells. The bacteria produce essential nutrients for the cicadas that the animals neither receive from their sap diets nor produce themselves…these bacteria have extreme and unique features." (Whiteman 2009)
Learn more about this functional adaptation.
- McCutcheon JP; McDonald BR; Moran NA. 2009. Convergent evolution of metabolic roles in bacterial co-symbionts of insects. PNAS. 106(36): 15394-15399.
- Whiteman L. 2009. Secret to cicada's abundance: bacteria. LiveScience [Internet],