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Cicadas are insects from the Cicadidae family. The chimney-building cicadas at Musa belong to the Guyalna chlorogena (Walker) species.

Life cycle

During their brief life, adult cicadas mate, stimulated by the courtship calls
of the males.

B Before they die, the females deposit their eggs on tree branches.

A miniscule larva (2 mm) comes out of the egg, drops to the floor, and burrows.

The larvae live underground for several years, molting a number of times, until they become nymphs almost the size of adult cicadas. They feed on the sap found in the tips of tree roots (meristems).

Using their front legs, they excavate the soil, pushing it backwards. A nymph moves forward in a tunnel it opens ahead of it and close behind it. It sucks the sap of tree roots using its pointy and hard mouthpiece like a syringe, while digging its feeding tunnel at the same time.

At some point, while moving forward and backwards, the nymph changes direction and starts moving obliquely and then vertically.

Working from the bottom up, the nymph excavates a vertical well that can be up to one meter deep, the same way it digs the horizontal tunnel, by pushing the soil backwards; that is why the bottom of the well is closed.

The nymph builds a 15 to 40 cm tall chimney (photos 1 and 2) that is a continuation of the well (photos 3 and 4), raising the top part without ever opening or puncturing it. Building occurs at night between December and March. The chimney grows quickly (3-4 cm per night). During the six to eight months they stay inside the building, the nymphs are very active: they open and close the top in certain instances, repair the tower if damaged, and rebuild whenever necessary.   

Finally, between July and September, the nymph opens the top of the tower (photo 5) before leaving a few hours later (photo 6) to undergo metamorphosis (photo 7).

[1 and 2] Chimneys • [3] Top of a well after the removal of the chimney •
[4] Cement mold (M) of an 88 cm deep well (26 cm excavation) with the location of the chimney (C) •
[5] Opening of the chimney top • [6] Exit of the nymph • [7] Metamorphosis
Photo 1: César Fernandes • Photos 2, 3 and 4: Claude Béguin • Photos 5, 6 and 7: Vanessa Gama