Even when male cicadas stopped singing for the night, cicada-related chatter seemed to continue during the historic dual emergence in Illinois.

Their mating call and invasion of wooded areas and neighborhoods are the topic of conversation at work, dinner parties and social media. Here are a few answers to questions that may have come up lately.

How much longer will cicadas be around?

Cicadas should be gone by mid-to-late June. Sources vary, but the general timeline is between a month and six weeks after emergence. The Smithsonian National Museum of Natural History projected the emergence would last between three weeks and a month. According to the Illinois Department of Natural Resources, an adult periodical cicada’s life span is one month, and the University of Purdue predicted they would be gone in a month and a half.

How do cicadas know when to emerge?

The emergence of periodical cicadas may be based on a sort of molecular clock that somehow keeps track of the years, according to entomologist Gene Kritsky.

“That is what we’re looking for now,” Kritsky said in an interview with Entomology Today. “We suspect it is tied to yearly cycles of the trees they are feeding upon.”

Emergence is also temperature-driven, Kritsky said. He mentioned placing temperature probes in the ground before a cicada emergence, and said the insects came out over a two-week period after the soil temperature reached about 65 degrees.

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What kind of trees do cicadas like?

Cicadas are generalists that will lay their eggs in nearly any woody plant of the right diameter: about the size of a pencil, according to Ken Johnson, a horticulture educator with University of Illinois Extension.

However, cicadas like some places better than others. Among their favorites are oak, maple, hickory, apple, birch, dogwood, linden, willow, elm, ginkgo, and pear. Cicadas will avoid conifers, cherries, peaches, and plums, because they produce a lot of sap or gum, which could prevent eggs from hatching and nymphs from reaching the ground.

What time do cicadas go to sleep?

While there seems to be no definitive answer as to whether cicadas sleep at night, there is a lull in cicada activity after dusk. According to the University of Connecticut, no cicadas in the United States typically sing in the evening, although they may have periods of intense activity at dusk. Night-time singing is likelier to be the work of crickets, katydids and frogs.

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Are cicadas good for the environment?

Cicadas offer several environmental benefits, according to the U.S. Environmental Protection Agency. They are a valuable food source for birds and other insect-eating wildlife, they can aerate lawns and improve water filtration, and add nutrients to the soil as they decompose.

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Why are cicadas so loud?

That loud trilling is the mating calls of male cicadas, according to the Nature Conservancy. An obnoxious or unpleasant sound to some humans, it helps cicadas find each other and reproduce within a short amount of time. The sound can reach 80-100 decibels in volume — equal to a garbage disposal, lawn mower or jackhammer.

This article originally appeared on Journal Star: When will the cicadas be gone in Illinois?