Editing Periodical cicadas (section)

==Life cycle==
[[File:Snodgrass periodical cicada transformation.png|upright|thumb|Transformation from mature [[Nymph (biology)|nymph]] to adult]]
[[File:Cicada Final Molt and Darkening timelapse 14 2021-05-27.webm|thumb|Time-lapse of final molt and darkening, over 4.5 hours]]
[[File:17Year cicada chaos.webm|thumb|right|thumbtime=ghnew123|Emergence! Nearly all at once. Many do not survive, but with mass emergence, many will reach maturity to start the next generation.]]
[[File:17year cicada adults.webm|thumb|right|thumbtime=124|Adult cicada female creating a slit in twig and inserting eggs. The sound is of thousands of cicadas.]]
Nearly all cicadas spend years underground as juveniles, before emerging above ground for a short adult stage of several weeks to a few months. The seven periodical cicada species are so named because, in any one location, all members of the population are developmentally synchronized—they emerge as adults all at once in the same year. This periodicity is especially remarkable because their life cycles are so long—13 or 17&nbsp;years. 

In contrast, for nonperiodical species, some adults mature each summer and emerge while the rest of the population continues to develop underground. Many people refer to these nonperiodical species as [[annual cicada]]s because some are seen every summer. This may lead some to conclude that the non-periodic cicadas have life cycles of 1''&nbsp;''year. This is incorrect. The few known life cycles of "annual" species range from two to 10''&nbsp;''years, although some could be longer.{{cn|date=May 2024}}

The nymphs of the periodical cicadas live underground, usually within {{convert|2|ft|cm|0|abbr=on}} of the surface, feeding on the juices of plant roots.<ref>{{cite book |last=Marlatt|first=C. L.|author-link=Charles Lester Marlatt|title=The Periodical Cicada|location=Washington, D.C.|edition=71|publisher=[[United States Department of Agriculture]], [[Bureau of Entomology]]: [[United States Government Publishing Office|Government Printing Office]]|year=1907|access-date=July 26, 2021|oclc=902809085|lccn=agr07001971|chapter-url=https://archive.org/details/periodicalcicada71marl/page/123/mode/1up|chapter=The Habits of the Larva and Pupa.: The Food of the Larva and Pupa.|pages=123–125|url=https://archive.org/details/periodicalcicada71marl/page/n2/mode/1up|via=[[Internet Archive]]}}</ref> The nymphs of the periodical cicada undergo five [[instar]] stages in their development underground. The difference in the 13- and 17-year life cycle is said to be the time needed for the second instar to mature. When underground the nymphs move deeper below ground, detecting and then feeding on larger roots as they mature.<ref>{{cite journal |last1=White |first1=J |last2=Lloyd |first2=M. |year=1979 |title=Seventeen year cicadas emerging after eighteen years-a new brood? |journal=Evolution |volume=33 |issue=4|pages=1193–1199 |doi=10.2307/2407477|pmid=28563914 |jstor=2407477 }}</ref> 

The nymphs seem to track the number of years by detecting the changes in the [[xylem]] caused by [[abscission]] of the tree. This was supported experimentally by inducing a grove of trees to go through two cycles of losing and re-growing leaves in one calendar year. Cicadas feeding on those trees emerged after 16 years instead of 17.<ref name="Simon et al. 2022"/>

In late April to early June of the emergence year, mature fifth-instar nymphs construct tunnels to the surface and wait for the soil temperature to reach a critical value.<ref name=Williams/><ref>{{cite journal |last1=Heath |first1=J.E. |title=Synchronization of Emergence in Periodical "17-year" Cicadas (Homoptera, Cicadidae, Magicicada) |journal=American Midland Naturalist |date=1968 |volume=80 |issue=2 |pages=440–448|doi=10.2307/2423537 |jstor=2423537 }}</ref> In some situations, nymphs extend mud turrets up to several inches above the soil surface.<ref>{{cite book|last=Marlatt|first=C.L|author-link=Charles Lester Marlatt|chapter-url=https://archive.org/details/periodicalcicada71marl/page/91/mode/1up|chapter=Transformation to the Adult Stage.: Cicada Huts, or Cones.|pages=91–98|url=https://archive.org/details/periodicalcicada71marl/page/n6/mode/1up|title=The Periodical Cicada|location=Washington, D.C.|edition=71|publisher=[[United States Department of Agriculture]], [[Bureau of Entomology]]: [[United States Government Publishing Office|Government Printing Office]]|year=1907|oclc=902809085|access-date=July 26, 2021|via=[[Internet Archive]]}}</ref> The function of these turrets is not known, but the phenomenon has been observed in some nonperiodical cicadas, as well as other tunneling insects.<ref>{{cite journal |last1=Betard |first1=F.|title=Insects as zoogeomorphic agents: an extended review |journal=Earth Surface Processes and Landforms |date=2020|volume=46 |pages=89–109 |doi=10.1002/esp.4944 |s2cid=225534427|url=https://hal.archives-ouvertes.fr/hal-02911647/file/Accepted_manuscript_Betard_2021.pdf }}</ref>

The nymphs first emerge on a spring evening when the soil temperature at around {{convert|20|cm|in|0|abbr=on}} of depth is above {{convert|17.9|°C|°F|0|abbr=on|lk=on}}. The [[Crepuscular animal|crepuscular]] emergence is thought to be related to the fact that maximum soil temperatures lag behind maximum [[Solar irradiance|insolation]] by several hours, conveniently providing some protection for the flightless nymphs against [[Diurnality|diurnal]] sight predators such as birds. For the rest of their lives the mature periodical cicadas will be strongly diurnal, with song often nearly ceasing at night.

During most years in the United States this emergence cue translates to late April or early May in the far south, and late May to early June in the far north. Emerging nymphs may [[Ecdysis|molt]] in the grass or climb from a few centimeters to more than 100 feet (30 m) to find a suitable vertical surface to complete their transformation into adults. After securing themselves to tree trunks, the walls of buildings, telephone poles, fenceposts, hanging foliage, and even stationary automobile tires, the nymphs undergo a final molt and then spend about six days in the trees to await the complete hardening of their wings and [[exoskeleton]]s. Just after emerging from this final molt the [[Ecdysis|teneral]] adults are off-white, but darken within an hour.

Adult periodical cicadas live for only a few weeks; by mid-July, all have died. Their ephemeral adult forms are adapted for one purpose: reproduction. Like other cicadas the males produce a very loud species-specific mating song using their [[tymbal]]s. Singing males of the same ''Magicicada'' species tend to form aggregations called ''choruses'' whose collective songs are attractive to females. Males in these choruses alternate bouts of singing with short flights from tree to tree in search of receptive females.<ref name=magiiii/> Most matings occur in so-called chorus trees.<ref name=species/>

Receptive females respond to the calls of conspecific males with timed wing-flicks (visual signaling is apparently a necessity in the midst of the males' song) which attract the males for mating.<ref name=wingflick>{{cite web|title=Sexual Signals in Periodical Cicadas|url=http://www.magicicada.org/cooley/reprints/Cooley_Marshall_2001.pdf|publisher=Behaviour|access-date=17 January 2014|archive-url=https://web.archive.org/web/20130616091322/http://www.magicicada.org/cooley/reprints/Cooley_Marshall_2001.pdf|archive-date=16 June 2013|url-status=live}}</ref> The sound of a chorus can be literally deafening and depending on the number of males composing it, may reach 100&nbsp;[[Decibel|dB]] in the immediate vicinity. In addition to their "calling" or "congregating" songs, males produce a distinctive courtship song when approaching an individual female.<ref name=species />

Both males and females can mate multiple times, although most females seem to mate only once {{Citation needed|date=January 2024}}. After mating, the female cuts V-shaped slits in the bark of young twigs and lays about 20 eggs in each, for a total clutch of 600 or more. After about 6–10&nbsp;weeks, the eggs hatch and the nymphs drop to the ground, where they burrow and begin another 13- or 17-year cycle.
<gallery mode="traditional" heights="100px">
File:Magicicada emergence holes.jpg|''Magicicada'' nymph emergence holes
File:Brood X emergence turrets.jpg|Mud turrets that emergent [[Brood X]] ''Magicicada'' nymphs created in [[Potomac, Maryland]] near Washington, D.C. (June 30, 2021)
File:Premolt Brood XIII.JPG|Brood XIII ''Magicicada'' nymph prior to final molt in suburban Chicago (May 24, 2007)
File:MoltingMagicicadaCrop.jpg|''Magicicada'' molting
File:White cicada.jpg|[[Ecdysis|Teneral]] [[imago|adult]] Brood XIII ''Magicicada'' and [[exuviae]] after [[Ecdysis|molting]] in [[Highland Park, Illinois]] near Chicago. (May 2007)   
File:Newly molted Brood XIII.JPG|Teneral adult Brood XIII ''Magicicada'' in suburban Chicago (May 24, 2007)
File:Magicicada young.jpg|Mass of ''Magicicada'' Teneral adults and exuviae on vegetation
File:SD-1071.jpg|An adult Brood X ''Magicicada septendecim'' in [[Princeton, New Jersey]] (June 6, 2004)
File:Cicada Sex Brood X 2021-05-31 092614 1 crop.jpg|Two Brood X ''Magicicada''s mating in [[Bethesda, Maryland]] near Washington, D.C. (May 31, 2021)
File:Magicicada ovipositing.jpg|A Brood X ''Magicicada'' ovipositing eggs in a tree branch near [[Baltimore]], Maryland (May 26, 2021)
File:17 Year Cicada - Brood X laying eggs in a tree branch 2021-06-01 13 59 48.webm|A Brood X ''Magicicada'' laying eggs in a tree branch (video) (June 1, 2021)
File:cicada egg slits 20040606 200213 1.jpg|''Magicicada'' egg slits (circled in red)
</gallery>