Cicada Mania In Wisconsin?

. . . . not until 2024

Excerpted from: BIG BUGS, BUGS, IN THE NEWS, ODD INSECTS

Perhaps you’ve heard some buzz about periodical cicadas lately. These insects resemble our Wisconsin's typical “Dog Day Cicadas," which we see in mid-to-late summer they are orange and black with vibrant reddish eyes instead of a dull greenish color.

Parts of the US are currently seeing mass emergences of periodical cicadas, which appear by the millions every 13 or 17 years depending on the species. Wisconsin residents have been asking if this was the year for us to see them, but it’s not time for the big show . . . . yet.

Periodical Cicadas

Periodical cicadas are sorted into cohorts known as “broods”, which occur in particular geographic areas and emerge at specific points in time. For the most part, these insects are excellent timekeepers and some broods have been documented as far back as the 1600’s in the eastern US. There are entire websites and apps dedicated to these insects and their schedules, and scientists have labelled broods with Roman numerals to help differentiate the cohorts.

In Wisconsin, the situation is fairly straightforward as we only see a single brood: Brood XIII. Brood XIII’s 17-year cicadas last emerged in 2007, meaning that we’ve got 4 more years to wait until their mass emergence in 2024.

Interestingly, there have been a number of reports of periodical cicadas in Wisconsin over the last month or so. There are confirmed reports from the Lake Geneva area (Walworth County) a confirmed report from southeastern Dane County, and a suspected report from Sauk County. While most periodical cicadas stick to the schedule, occasionally some of these insects veer off course. These out-of-sync individuals are referred to as “stragglers.”

It turns out that Brood XIII has a history of these stragglers. In the late 1960’s, large numbers of stragglers were documented in the Chicago area. Likewise, many of the Chicago suburbs are seeing a similar phenomenon this year. With that said, we did technically see some periodical cicadas this year, but we’ll have to wait a few more years before the real fireworks.

Cicada Life Cycle

The cicada life cycle has three stages: eggs, nymphs, and adults. Female cicadas can lay up to 600 or more eggs divided among dozens of sites — generally in twigs and branches. After 6 to 10 weeks, young cicada nymphs hatch from their eggs and dig themselves into the ground to suck the liquids of plant roots. They spend their entire developmental period in these underground burrows before molting their shells and surfacing as adults to mate and lay eggs.

The developmental process varies in length, but periodical broods emerge in synchrony depending on the year and soil temperature. They wait for the right conditions for breeding, which are when the ground thaws to 65°F in a brood’s designated year. It’s not clear why these cicadas have such distinct and oddly timed cycles, though some scientists theorize it has to do with avoiding predators.

Periodical cicadas do not create destructive plagues, as some locusts do, though as many as 1.5 million cicadas may crowd into a single acre. Unlike locusts, cicadas don’t eat vegetation but rather drink the sap from tree roots, twigs, and branches. Large swarms can overwhelm and damage young trees by feeding and laying eggs in them, but older trees usually escape without serious damage as cicadas don’t stick around for long. Adults die off within about four to six weeks after emerging.

Vocalizations

Cicadas are also known for their buzzing and clicking noises, which can be amplified by multitudes of insects into an overpowering hum. Males produce this species-specific noise with vibrating membranes on their abdomens. The sounds vary widely, and some species are more musical than others. Though cicada noises may sound alike to humans, the insects use different calls to express alarm or attract mates.

Behavior

Cicadas spend the majority of their lives underground. They spend years developing into adults before they can emerge to sing, mate and lay eggs.

They typically live in trees, feeding on watery sap from xylem tissue and laying their eggs in a slit in the bark. Most cicadas are cryptic. The vast majority of species are active during the day as adults, with some calling at dawn or dusk. Only a rare few species are known to be nocturnal.

Female cicadas usually lay their eggs in woody plant tissues that drop from the plant when, or shortly after, the eggs hatch. Newly hatched nymphs burrow into the ground where they suck juices from roots of perennial plants. Nymphs usually undergo five molts during the several years required to reach maturity. Although not ordinarily considered a pest, the females, if numerous, may damage young saplings during their egg laying.

Further Reading:

 Beavers — Nature's Hydrologist, Part 2
 Garter Snakes — The Gardener's Friend
 Wisconsin Native Salamanders
 Goundhog or Woochuck: All The Facts
 Voles, Both The Good and The Bad