July 3, 2015

How Long Does a Periodical Cicada Emergence Last?

Filed under: FAQs | Magicicada | Periodical — Dan @ 2:47 pm

People often ask: “how long do cicadas last”, “how long will the cicadas be here”, or “how long do cicadas live above ground”?

People probably ask these questions, sadly, because they are tired of listening to the love songs of these cicadas. Like the saying “it is darkest before the dawn”, however, silence is typically a few weeks away.

The length of a local emergence:

The typical periodical cicada emergence will last between 6 to 8 weeks in a single location, with significant chorusing (singing) lasting about 3 to 4. Cool weather or rain can prolong an emergence.

The research paper Emergence of 13-Yr Periodical Cicadas (Cicadidae: Magicicada): Phenology, Mortality, and Predator Satiation by Kathy S. Williams, Kimberly G. Smith, and Frederick M. Stephen¹ contains a wonderful study of the arc of a periodical cicada emergence. The entire emergence event takes place within 8 weeks, from the first emerged cicada to the last dead cicada (see Fig 4 in that document ¹). The number of live adults reached its peak within two weeks and then began to die off in significant numbers two weeks after that, due mostly to natural causes. After that, the population of cicadas gradually dwindles due to natural deaths and predation.

Length of the chorusing:

Male cicadas will not begin chorusing at the start of an emergence, for a couple of reasons: 1) the first cicadas to emerge, which are primarily males (Fig 3 in ¹), are mostly lost to consumption by predators (Fig 6 in ¹), 2) Males can’t sing until their adult bodies are fully sclerotized, and 3) they need a significant number of males present before they will chorus. That said, chorusing typically begins within two weeks ². Males will continue to chorus until enough cicadas die to no longer sustain the chorus, which is why the chorus lasts less than a month.

Length of the emergence of an entire brood:

An emergence spanning multiple states could last between 8 to 10 weeks from when the first cicadas emerge in the South to when the last cicada dies in the North. For example, Brood XXIII began appearing the second to last week of April in Mississippi, and there were likely some left in southern Illinois up until the last week of June.

References:

¹ Kathy S. Williams, Kimberly G. Smith, and Frederick M. Stephen, Emergence of 13-Yr Periodical Cicadas (Cicadidae: Magicicada): Phenology, Mortality, and Predator Satiation, (1993), Ecology, Volume 74, Issue 4 (Jun., 1993), 1143-1152
² Kathy S. Williams and Chris Simon, The Ecology, Behavior, and Evolution of Periodical Cicadas, (1995), Annu.Rev. Entomol. 40:269-95

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June 28, 2015

How many kinds of cicadas are there?

Filed under: FAQs — Dan @ 12:46 pm

How many kinds of cicadas are there? That depends on what you mean by kinds.

There are over 190 species in the U.S.A. and over a dozen in Canada. Australia has hundreds of cicadas and you can find a list of them here.

World wide, there are over 3,390 species, with new species described every year (I counted them all in this book)!

A good source of papers about new cicadas is Zootaxa.

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Do Cicadas Stink?

Filed under: FAQs — Dan @ 10:21 am

Unlike an insect like the Stink Bug (Pentatomidae) cicadas do not stink while alive.

When cicadas are dead though, their rotting bodies can be quite putrid, especially periodical cicadas.

Even in my collection of deceased cicadas, only the periodical cicadas smell bad.

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What do Cicadas Eat and Drink?

Filed under: Anatomy | FAQs — Dan @ 9:52 am

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.

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

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Do cicadas pee?

Filed under: Anatomy | Chremistica | FAQs | Magicicada — Dan @ 8:11 am

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:

Sources:

¹ Records 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

² The 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.

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June 27, 2015

Can you see letters like W & P on a cicada’s wings?

Filed under: FAQs | Pop Culture — Dan @ 9:45 pm

If you use your imagination, you can see the shapes of letters on the wings of some cicadas.

W in cicada wing

There is an “urban legend” that W means there will be a War, and P means there will be Peace.

Aside from letters, some people say they see a lightning bolt! âš¡ï¸

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What is Predator Satiation?

Filed under: FAQs | Magicicada | Periodical — Dan @ 9:24 pm

Why are there so many Magicicada periodical cicadas, and what does it have to do with the survival of their species? One of the answers is: Predator Satiation.

A predator is any animal that would eat a periodical cicada, i.e., birds, raccoons, squirrels, dogs, snakes, etc. Satiation, in the case of cicadas, means to supply predators with enough cicadas to eat until they are wary of eating and thus avoid them completely.

Predator satiation works like this:
1) Periodical cicadas emerge in tremendous numbers.
2) Adult cicadas are often timid, even after having sclerotized.
3) The first cicadas that emerge are eagerly consumed by predators.
4) The predators are so overwhelmed by the bounty of easily eaten cicadas, that they fill themselves to the point of disgust and exhaustion.
5) This gives the remaining cicadas a chance to escape the predators.

The first periodical cicadas are literally “fodder”, in the battle between predators and periodical cicadas, to use a war/video game analogy.

Look at this periodical cicada: it is thinking “hopefully this creature will eat me, so my siblings will live on!”

Magicicada on my finger by Dan from Cicada Mania on Vimeo.

The research paper Emergence of 13-Yr Periodical Cicadas (Cicadidae: Magicicada): Phenology, Mortality, and Predator Satiation by Kathy S. Williams, Kimberly G. Smith, and Frederick M. Stephen (Ecology, Volume 74, Issue 4 (Jun., 1993), 1143-1152) is worth reading if you are interested in this topic. They found that predation of cicadas peaks during the first few days of the emergence, and doesn’t resume in significant numbers until three weeks later (see figure 6, if you read the paper).

Unfortunately, this strategy could be detrimental to periodical cicadas in areas with dwindling populations, where there isn’t enough of them to satiate the predators completely.

This strategy might also be used by other types of periodical cicadas like the Chremistica ribhoi of India, or cicadas that emerge in large numbers like Callogaeana festiva of south-east Asia.

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What eats cicadas?

Filed under: FAQs | Massospora — Dan @ 1:32 pm

What eats cicadas? A better question is: what doesn’t eat cicadas?

Pretty much every creature with a mouth will eat a cicada, given the chance. Even organisms without mouths like fungi will consume cicadas.

People, pets, rodents, marsupials, reptiles, birds, fish, insects, arachnids — virtually any creature will eat them.

Some insects are known for specifically preying on cicadas, for example, Cicada Killer Wasps are well known for capturing cicadas for their larvae to eat them.

What eats them when they’re underground? When they’re underground they’re often eaten by moles and other furry insectivores, but enough of them escape the moles for the species to survive.

Read are cicadas safe to eat if you’re planning a cicada buffet.

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What are stragglers?

Filed under: Accelerations | FAQs | Periodical | Periodical Stragglers — Dan @ 1:02 pm

Periodical cicadas often emerge in years before or after they are expected to emerge. When periodical cicadas don’t emerge on schedule we call them stragglers, regardless of whether they show up early or late. Typically cicadas with a 17-year lifecycle will emerge 4 years early, and cicadas with a 13-year cycle will emerge 4 years late.

Probability of Straggling chart from Chris Simon
This image indicates the probability of Magicicada straggler emergences. Courtesy of cicada researcher Chris Simon.

People hear the word straggler and assume it means something that lags behind, but that is a laggard. A straggler can mean something that has deviated from an expected date/time or moved away from others of its kind. That said, periodical cicadas that emerge early can also be called precursors, but in the scientific literature, they are called stragglers.

Visit Brood Chart to see when stragglers will be most likely.

Extremely likely stragglers in the next few years:

2020: Brood XIII 4 years early.
2021: Brood XIV 4 years early.
2025: Brood I 4 years early.

Likely stragglers in the next few years:

2020: Brood X 1 year early.
2021: Brood IX 1 year late.
2022: Brood X 1 year late.
2023: Brood XIII 1 year early.
2024: Brood XIV 1 year early.

Accelerations

An acceleration occurs when periodical cicadas straggle in numbers significant enough to sustain future generations. In other words, a large population of a 17-year brood emerge in just 13 years, they avoid being eaten by predators, they mate and reproduce, and then 17 years later their offspring emerge in large enough numbers to reproduce and sustain their population. This is one reason why two different broods might exist in the same area. ¹

It is thought that Brood X was formed when a group of Brood XIV accelerated 4 years (they emerged in 13 years, rather than 17). Then Brood VI came from Brood X, and Brood II came from Brood VI. Brood XIV -> X -> VI -> II is called the “main sequence”¹.

Accelerations may have been more prevalent and successful (successful in terms of sustaining future generations) in the past when much of eastern North America was forests, and there was no human intervention or destruction of habitat to interfere.

References

¹ Monte Lloyd & Jo Ann White. Sympatry of Periodical Cicada Broods and the Hypothetical Four-Year Acceleration. Evolution, Vol. 30, No. 4. (Dec., 1976), p. 795.

Here’s a paper that discusses 13-year Magicicada emerging 4 years early: David C. Marshall, Kathy B. R. Hill, and John R. Cooley “Multimodal Life-Cycle Variation in 13- and 17-Year Periodical Cicadas (Hemiptera: Cicadidae: Magicicada),” Journal of the Kansas Entomological Society 90(3), 211-226, (1 July 2017). https://doi.org/10.2317/0022-8567-90.3.211

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Can cicadas see?

Filed under: Anatomy | FAQs — Dan @ 12:45 pm

Yes, cicadas can see. People might assume that cicadas cannot see because they are slow to move when approached or are easy to capture.

Cicada Eyes

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).

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