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Extension Entomology

Easy Math: 2015 minus 1998 = 17

—Dr. Robert Bauernfeind

Algebra? Trigonometry? Calculus? Not my strongest subject matter. Never was — never will be! But simple math, I can handle. The answer of “17” can only mean one thing to an entomologist: 17-year periodical cicadas. By the end of May and into June, the “buzz” created by massive numbers of newly emerged periodicals will create quite a “buzz” mainly amongst citizens of eastern Kansas.

With their distinctive appearance (black body, blood-red beady eyes and orange-veined clear/transparent wings), there can be no mistaking periodical cicadas for any other insect. In actuality, the simple above-mentioned descriptors are (for lay people) not utilized in taxonomic keys used by systematists to identify/classify cicadas.

Whereas there is a tendency to lump/consider periodical cicadas as “one”, there actually are 3 separate species of 17- year periodical cicadas. Only Magicicada cassinii and M. septendecim have been officially documented as occurring in Kansas. If one wished to differentiate which is which, the body of the smaller cassinii measures .8-inch long with an abdominal width of ¼-inch, whereas the more robust septendecim measures 1.1-inches in length with an abdominal width of 1/3 – inch (quite evident if comparing specimens side-by-side). If not wanting to take measurements, simply flip the specimens over and examine the bottom of their abdomens: cassinii is entirely black whereas septendecim is orangish. Although discernable but a little more difficult to observe is the area between the eye and base of the forewing: black for cassinii and orangish for septendecim. All this being said, by far, cassinii are more common and likely to be encountered than septendecim. Of the 4,437 periodicals that I collected from 37 counties in 1998, 98.7% were cassinii.

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Without seeing an actual specimen, one can discern whether cassinii or septendecim are present. That is, the call produced by cassinii is a continuous somewhat high-pitched buzzing possibly with come ticks interspersed, while the call of septendecim is a more hollow “weeeee whoa weeeee whoa ………..” (sometimes people say it sounds like “pharaoh ……”. Only males are capable of calling/chorusing —- the purpose being to attract females for mating purposes.

Probably the main complaints lodged by people against periodical cicadas have to do with the appearance of emergence holes in the ground (A), occasionally mud turrets produced by nymphs prior to their emergence (B), large number of nymphal exuvia (“skins”) from which adult cicadas emerged (C), and the noise created by the clusters of congregated males (D).

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Also, the egglaying activities can kill tips of branches thus causing the appearance of dead branch tips, which is but an aesthetically brief and inconsequential event.

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The following color-coded map details the documented distribution of periodical cicadas in Kansas. I would appreciate receiving any reports of periodical cicada activities that you encounter —— Phone: 785-539-7510; e-mail: rbauernf@ksu.edu. Of special interest to me would be reports from Morris, Republic, McPherson and Harvey counties. I would visit those counties/sites for the purpose of collecting specimens for incorporation into our Departmental MEPAR holdings. I plan on visiting specific sites in Reno and Stafford counties (where periodicals were reported in 1998) for collection purposes. And I would especially appreciate reports from “uncolored/blank counties” for the purpose of possibly determining the western range of periodical cicadas in Kansas.

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All this being said, the 2015 emergence of Brood IV periodical cicadas (which includes portions of Iowa, Nebraska, Missouri and Oklahoma) was initiated in 1998 when 1st instar nymphs hatched, dropped to the ground and burrowed in. During the past 16 years, they fed by inserting their piercing sucking mouthparts into the xylem tissues of tree and woody shrub hosts. The now fully-developed 5th instar nymphs currently are waiting for soil temperatures to reach the proper temperature (cited to be 64oF) which signals them that the time has come that they should emerge from their underground habitat. After emerging (A), the skin down its back will split, and a “new adult” will emerge (B). Initially it will be white and soft (C). Over the next several hours, it will darken and take on its characteristic coloration (D). However, the exoskeleton will still be soft. An additional 4-5 days will be required for the exoskeleton to harden. It is at this point that cicadas will take flight, males will call, females will respond and mating will occur.

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The female then will use her serrated ovipositor to slice into and create cavities in twigs into which she will insert up to 20 eggs. She will repeat this activity as many times as is required for her to deposit her full complement of eggs which may total up to 600. Six to 10 weeks later (a time at which all of the periodical cicadas will have died), the newly hatched nymphs drop to the soil burrow into the ground, feed for 16 years and reappear/emerge in 2032!

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