What are those alien like shells that you can see hanging on trees and plants?
That, my friend, is an exuviae, our new word for today. These are the remains of an exoskeleton after a Cidada has moulted.
Side note: This is not like a chrysalis from a butterfly, as this is only a “moult” or shedding of the skin, not a complete metamorphosis.
Cicadas have prominent eyes set wide apart that you can see clearly on the shed, with short antennae, and membranous front wings. They have an exceptionally loud song, produced in most species by the rapid buckling and unbuckling of drumlike tymbals.
When the eggs hatch, the newly hatched nymphs drop to the ground and burrow. Cicadas live underground as nymphs for most of their lives at depths down to about 2.5 metres In the final nymphal instar (development stage), they construct an exit tunnel to the surface and emerge They then climb up a handy tree or plant and moult (shed their skins) for the last time, and emerge as adults. The exuviae or abandoned exoskeletons remain, still clinging to the plant.
Most cicadas go through a life cycle that lasts from two to five years.
Here are two pictures of adult cicadas of different species. And yes, these are the very noisy insects you can hear in spring and summer.