It’s been about six weeks since the emergence of Brood VIII in Pennsylvania, Ohio, West Virginia and Oklahoma. Now (first week of August) is a good a time as any to check for periodical cicada nymphs that have hatched from eggs laid in branches. Once they hatch they’ll find their way to the ground, where they’ll find and begin feeding on roots for the next 17 years.
Look on branches where cicada laid their eggs.
An illustraition of egg nests:
A nymph on a branch with adult male finger for comparison:
One of the most frequently asked questions we receive is: “what do cicadas do“? This question is similar to the question “what is the purpose of cicadas” — the answers to both questions help people understand why these fascinating, unusual creatures exist at all.
The simplest reduction of their life cycle is:
1) They hatch from an egg.
2) They burrow underground where they will drink from plant roots for most of their lives.
3) They leave the underground and become adults.
4) The males make sounds that attract females.
5) Males & females court & mate.
6) Females lay fertilized eggs in the branches of plants, and the cycle continues.
7) They die.
The specifics of a cicada’s life cycle varies from species to species, but here is a more detailed view of what cicadas do:
From egg to 1st instar nymph:
1) Cicada nymphs hatch from eggs.
2) Nymphs feed on plant fluids which they access thanks to the egg-nest groove made by their mothers.
3) They leave the groove, and drift to the ground. Their descent to the ground doesn’t hurt them because they weigh so little.
4) Once on the ground, they dig into the soil until they find small rootlets, from which they will feed.
5) Underground, they will tunnel/dig…
6) and establish a cell…
7) from where they’ll comfortably feed. Cicadas feed on the xylem sap of plants. With the help of bacteriathey transform the water, minerals and amino acids found in tree fluids to the tissues of their own bodies.
8) They pee, in fact they seem to use excess plant fluid to moisten soil to help mold the walls of their cells.
9) Throughout their life underground they will move from root to root… as plant root systems change with the seasons, when roots die off, or perhaps to avoid predators.
23a) If you are a Male cicada, you are going to sing… unless you belong to a species that cannot sing, in which case, you’ll move your wings in a way that will produce a sounds.
There are many types of songs: a) distress calls, b) calls to establish territory, c) calls to attract females, d) including choruses of many cicadas and e) courting calls
23b) Female cicadas, and some male cicadas, move their wings to make sounds, also in an effort to attract and engage a mate.
24) Most cicadas (aside from Magicicada during the early days of their adult lives) will try to avoid being eaten by predators.
25) They’ll fly, of course.
26) Cicadas, like Magicicada, will establish chorusing centers, which are places where the male cicadas sing together and females come to meet them.
27) Male and female cicadas will court…
28) and mate…
29) the female cicada will lay her eggs in grooves (ovipositing) she etches into a suitable plant stem, and we’re back to step 1.
30) The last thing cicadas do, of course, is die, and return the nutrients found in their bodies to the soil, where they will be broken down and absorbed by the plants they fed upon.
Some things cicada do not do:
Here are some things cicadas do not do:
1) They don’t seek shelter during the fall months (i.e. they don’t try to live inside your house), unlike Ladybugs or Stinkbugs.
2) They don’t sting or otherwise pass venom onto people.
3) They don’t chew plant leaves, like caterpillars or grasshoppers.
4) They don’t dump garbage in the ocean.
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.
Cicadas 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.
1The Ecology, Behavior, And Evolution Of Periodical Cicadas, Kathy S. Williams and Chris Simon, Annu.Rev. Entomol. 1995. 40:269-95
2Xylm 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
More than a few people have asked Cicada Mania: “do cicadas pee”? Absolutely, cicadas do pee. There are a couple of reasons why:
They pee to eliminate excess fluids taken in while drinking xylem (1).
They pee to eliminate non-essential amino acids (2).
Underground, they could use excess fluid to help moisten and remold their tunnels & cells (2).
They might, in some cases, even use it to keep ants from attacking… (3)
You may have been under a cicada-filled tree on a sunny day and felt a sprinkle or two. Don’t worry, it is just watery tree sap (xylem) passed through a cicada.
A detailed explanation of the experience courtesy of Les Daniels:
I’ve experienced this several times where I was on the receiving end of this artificial rain. When many cicadas congregate on warm days, they feed on the tree fluids and often urinate ‘piss’ while doing so. This bug urine is called ‘honeydew.’ The little buggers have pelted me several times while I was observing a little ‘too’ close. It isn’t uncommon. Lastly, the ‘honeydew’ does not stain or stink. In fact, it feels like raindrops.
Some cicadas seem to pee more than others, for instance, the Chremistica umbrosa of South-East Asia. If you walk under an umbrosa, you will need an umbrella! (The Latin root of both words, umbr means shade). Here is a video of Chremistica umbrosa:
1Records Of The Cicada, Chremistica Umbrosa (Distant, 1904) In Singapore, With Accounts Of Its Mass Emergence (Homoptera: Cicadidae: Cicadinae), Tzi Ming Leong, Aminurashid and Benjamin P. Y-H. Lee, NATURE IN SINGAPORE 2011 4: 163—175, 15 June 2011
2The Ecology, Behavior, And Evolution Of Periodical Cicadas, Kathy S. Williams and Chris Simon, Annu.Rev. Entomol. 1995. 40:269-95
3 The documentary The Queen of Trees by Deeble & Stone features a segment about Fig Cicadas, that expel pee, sweet with the phloem sap of the fig tree, which is enjoyed by ants and monkeys, which has the side benefit of keeping those predators and nuisances away.
Yes, cicadas can see. People might assume that cicadas cannot see because they are slow to move when approached or are easy to capture.
Cicadas have 5 eyes. Two large compound eyes, which are used to visually perceive the world around them, and three small, jewel-like, simple eyes called ocelli. We believe the ocelli are used to perceive light & darkness. The fact that there are three of them, arranged in a triangle, may help them triangulate the direction of the sun or the movement of a shadow.
The reason they are easy to capture right after they have molted is that their body parts are not hardened and ready to react quickly. The reason they are easy to catch once their bodies are hardened is often that they want to be caught, due to a species survival strategy called predator satiation (more on that in a future article).
No. When many types of cicadas first emerge from their nymphal skin they are white in color. Gradually, their bodies become a darker color. Some take longer than others to change. Some die before the change can occur, and their corpses remain white.
This is a photo of a teneral (soft) Magicicada:
Its skin will eventually turn black and orange.
The are some cicadas, like the Tibicen pruinosus fulvus Beamer, 1924, that retain their lighter, teneral colors, but they are not albinos. Note: fulvus means yellow.