The shed exoskeleton of an annual, “dog day” cicada seen in Chicago’s Lincoln Square neighborhood on July 9, 2024. (Patty Wetli / WTTW News)
From emergence holes in the parkway to molted shells on trees to ear-splitting mating calls, cicadas have very much arrived in Chicago.
Just not the ones everybody was obsessing over a month ago.
Some folks have mistakenly identified the newest arrivals as late-comers to Illinois’ historic party of 13-year and 17-year periodical cicadas, which briefly dominated the news cycle and popular culture when they first appeared.
But there’s no fancy Roman numeral brood name attached to the current swarm.
Because they turn up every year beginning in July, these bugs are all simply lumped together as “dog day” cicadas, even though there are roughly a dozen different species of “dog days” and as many sub-species in the U.S., not counting a member of the family that’s now extinct but formerly existed solely in Bermuda.
An annual cicada, left, photographed in Chicago on July 8, 2024, and a periodical cicada, photographed in a suburban Cook County forest preserve in May 2024. (Patty Wetli / WTTW News)
Up close, it’s easy to distinguish an annual cicada from a periodical thanks to some telltale differences.
Annual cicadas are not only noticeably bigger than their periodical cousins but the real giveaway is their coloring: the annual’s signature hue is green versus periodical’s red.
In terms of lifecycle, the annual cicada’s is almost an exact duplicate of the periodical’s. The insects spend their juvenile stage underground, living off tree roots; they emerge, find a surface to climb and shed their exoskeleton; fly into a tree; mate; lay eggs in a tree limb (if female); and die.
The eggs hatch and then the larva head underground and repeat the cycle within two to five years, rather than periodical’s longer 13- or 17-year waits.
Annual cicadas also stagger their emergence over a longer timespan, and they live slightly longer than periodicals, all of which means they’ll be serenading each other — and us — well into September.
Contact Patty Wetli: @pattywetli | (773) 509-5623 | [email protected]
