Periodical Cicadas

By Taylor on July 11, 2014 in Blog

INHF President Joe McGovern with Alex and Henry, 2014 land stewardship interns, at Snyder Heritage Farm. Henry is holding one of the 17-year cicadas as Joe explains their life cycle.

This summer marks the emergence of the 17-year-cycle Brood cicadas III, Magicicada spp, in Iowa and  northwestern parts of Illinois. There are three species of 17-year-cycle cicadas, and they can be found in the northern part of the United States. Most of them emerge during the months of May and June.

The 17-year cicada spends its juvenile years in underground burrows. A few weeks before emerging in its seventeenth year, the cicada begins to tunnel upward. The day of exit seems to correspond to soil temperature, and they emerge in large quantities. Many people mistakenly refer to cicadas as locusts; however, a locust is a type of grasshopper. Cicadas have black bodies, red eyes and orange-veined wings.

When the cicadas emerge, males make a loud buzzing noise, which is a species-specific mating call that is sexually attractive to female cicadas. Males will make short flights until they locate a female partner. Females then lay up to 600 eggs in tree limbs and twigs. After six to ten weeks, the eggs hatch, and the newborn cicadas burrow underground where they spend their first five juvenile life stages. By the time the newborns hatch, the adults have died.

Cicadas do not possess defense mechanisms (stinging, biting, etc.), and they are not poisonous. When approached, a cicada will simply try to fly away. They can cause damage to young trees and shrubs if too many feed on or lay eggs in the same plant. This damage is referred to as “flagging,” which is the breaking of peripheral twigs. To tell if flagging has occurred, look for twigs turning brown from distress and breakage. Orchard and nursery owners should avoid planting new trees or shrubs in a year cicadas are set to emerge. Mature trees should not be affected.

To learn more on cicadas, click here.