You might notice that some cicadas have shriveled-up or otherwise damaged wings. Most of the time, wings become damaged during the molting process (ecdysis), specifically while their wings harden (sclerotize). Their wings and body are most vulnerable when they are still soft.

Some reasons why a cicadas’s wings might not get the chance to inflate and harden:

• If a cicada molts and its wings are not able to hang downward they won’t inflate with fluids and form properly.
• Cicadas often trample each other in the rush to find a place on a tree to molt.
• Harsh weather, like wind and rain, knock them to the ground or bend their wings when they’re soft.
• Malnutrition.
• Physical weakness or defects.
• Fungi infection.
• Predator attacks.

Just 10 Magicicada (American periodical cicadas) generations ago, the U.S. was mostly forest. Back then it was easy to find a vertical surface to molt on, or a plant stem to hang from. Today most forests have been replaced with agriculture, buildings, lawns, roads, sidewalks, parking lots, etcetera — so it has become increasingly difficult for periodical cicadas to find a good place to hang.

Magicicada can afford to lose a large number of their population due to wing malformations and other critical defects because there are simply so many of them — this loss falls in line with their predator satiation strategy.

However, if Magicicada cicadas lose too much habitat, they will go extinct (brood XI went extinct about 60 years ago). Lawns, roads, sidewalks, and other features of our human habitat create surfaces that are insalubrious for cicada molting.

In the video below, you will see a cicada molting. Note that its wings are able to hang downward and inflate to form properly shaped wings. If the cicada tried to molt on a vertical surface, the odds are its wings would be crumpled.

In the image below, there is a Neotibicen tibicen (not a periodical cicada) that sclerotized (hardened) before completely shedding its nymphal skin.

Although adorable, this Neotibicen will never sing or fly.

Cicadas “eat” / drink something called xylem (sap), which is a watery tree fluid containing amino acids and minerals. Cicadas drink rather than eat.

People probably ask “what do cicadas eat” because they are afraid that cicadas will eat their flowers and garden fruits and vegetables. Cicadas lack mouthparts that can chew and swallow vegetation. Your tomatoes and marigolds are safe.

How does a cicada drink xylem? The cicada’s mouth parts (aka rostrum or beak) are in the shape of a straw, which can pierce rootlets, roots and branches.

• The labium form the outside of the beak of the cicada; inside the labium is the stylet which is comprised of the mandibles and maxillae, which the cicada uses to pierce plants and drink their sap.
• The labrum connects the labium to the rostrum…
• The rostrum, or what people call the “nose” of the cicada, contains enourmous pumping muscles (1) that suck the xylem up into the cicada.
• The cicadas’s polymerized, viscous saliva plugs up any holes their mouth parts create (2), so a root will not continue to leak xylem when the cicada moves on to a new root. They put the cork back in the wine bottle, so to speak.

Cicadas are able to derive nutrition from the xylem thanks to bacterial endosymbionts that live in the cicada’s gut.

Cicada are known for drinking xylem from tree roots (as nymphs) and branches & twigs (as adults), however, when they are small they must rely on grasses, and possibly other small plants for nourishment.

• Young cicada nymphs are smaller than a grain of rice when they first begin feeding so the tiny roots of grasses are the best fit for their small beaks.
• Grass roots are likely the first roots a young cicada nymph will encounter, as they are close to the surface.
• Deciduous trees shed their rootlets in winter months, but grasses do not (2). This is not an issue in tropical regions.

Perhaps the reason why periodical cicadas are “attracted to woodland edges and exposed aspects, especially for chorusing and ovipositing” (1) is their offspring will be more likely to find the roots of grasses in those areas. Young nymphs would be unlikely to find suitable tiny roots deep in a shady forest.

Once the cicada nymph is larger, they can burrow to larger and more permanent tree roots, and feed on there.

It is interesting to note that not all cicadas feed on trees. Some feed on sugarcane, which is a giant grass (we’re back to the grasses again). The Brown sugarcane cicada (Cicadetta crucifera) and Yellow sugarcane cicada, (Parnkalla muelleri) of Australia feed on the sugarcane plants and cause damage to plants.

Read more:

Do cicadas bite or sting.

Sources:

• ¹ The Ecology, Behavior, And Evolution Of Periodical Cicadas, Kathy S. Williams and Chris Simon, Annu.Rev. Entomol. 1995. 40:269-95
• ² Xylm Feeding by Periodical Cicada Nymphs on Pine and Grass Roots, With Novel Suggestions for Pest Control in Conifer Plantations and Orchards, Monte Lloyd and Joann White, OHIO J. SCI. 87 (3): 50-54, 1987