The emergence of cicadas may be triggered by their sensing of cyclical cues from nearby tree roots.
"Three species of cicada (genus Magicicada) with remarkable rhythms live in the United States. In the south, nymphs spend 13 years underground before emerging within a few days of each other and transforming into adults. In the north, the nymph stage lasts 17 years…However, recent studies suggest that the cicadas may use cues from nearby tree roots (such as sap quality, which varies cyclically) to time their emergence." (Shuker 2001:97)
Learn more about this functional adaptation.
- Shuker, KPN. 2001. The Hidden Powers of Animals: Uncovering the Secrets of Nature. London: Marshall Editions Ltd. 240 p.