MAY
1990

 

 

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

 

 

 

 

05-24-90

The Year of the Cicada

The cicadas are coming!   The cicadas are coming!

Indeed, many folks who live in northern Illinois, southern Wisconsin or in Lake, Porter and LaPorte counties in Indiana will probably see and will certainly hear cicadas this June.  You see, Brood XIII of the 17-year race of the periodical cicada will emerge in 1990, announcing its presence with an incessant cadence of high-pitched sound.

The cicadas that emerge this year are termed XIII to distinguish them from other broods of this insect in different years and localities.  For instance, next year Brood XIV will appear in many counties in southwestern Indiana.

Years ago when much of the eastern United States was covered with hardwood forests, a brood of periodical cicadas probably emerged each year.  Today, some broods have been lost entirely, and most are confined to localized areas.

Periodical cicadas should not be confused with annual cicadas, which emerge during July and August.  Annual cicadas are sometimes called ‘harvestman' or ‘dog-day cicadas' because of their emergence time, which is associated with the dog days of summer.

The periodical cicada has the longest developmental period of any insect.  As the name suggests, it takes 17 years for the insect to complete its life cycle.

This year's brood of the periodical cicada began its life in 1973.  That was before Watergate, so Richard Nixon was still president, and that fall the Oakland A's beat the New York Mets in the World Series.  Students graduating from high school this spring may not have been born by 1973 or, at least, were still in diapers.

Periodical cicadas begin their life as an egg laid under bark of woody plants.  The eggs hatch and the nymphs drop to the ground, where they dig into the soil and feed by sucking sap from the roots of trees.  Seventeen years later, the nymphs emerge from the soil, where they shed their last shell to become winged adults.

Emergence normally occurs during the nighttime hours.  The cover of darkness helps protect the insect because the newly emerged adult is soft-bodied and unable to fly.  At this time, it is easy prey to cicada eaters, of which there are many.

The new adults begin their appointed role in life that of mating and laying eggs.  Male cicadas attract mates by singing.  The noise – or, rather, singing – is produced by two, drumlike membranes on the first segment of the abdomen.

Is it really necessary for the cicadas to make such a racket?   No one knows for sure.  But wouldn't most folks feel like singing at the top of their lungs after spending 17 years underground darkness?

 

Writer: Tom Turpin
Editor: Carol McGrew