When Spencer Campbell leaves his office at the Morton Arboretum in Lisle, he is almost surrounded by cicadas. “I almost cannot walk without stepping on them,” the Plant Clinic manager at the arboretum said. Just a few miles away, in Kane County, for example, some people have yet to see their first cicada.
Such is the unpredictability and uneven nature of the emergence of the 17-year life cycle insect that will devour young trees, but is not dangerous – maybe just annoying – to humans. “It’s not evenly spread throughout the area,” Campbell said. Historically, the insects have been seen more heavily in DuPage County, where there a lot of mature trees, rather than in Kane County, where there is more recent construction and a lot of agricultural land.
The cicadas spend 17 years in the ground, feeding on tree roots. When they emerge every 17 years, they look for more trees to feed on, and then mate. If an area, such as farmland or developed land, does not have a lot of trees, they likely would not be in that area.
People living in an area of newer construction might be in a place where the insects were disturbed when the ground was dug up. Campbell said the insects do not fly very far from their original location, maybe about a half-mile from where they come up from the ground. So it is possible some will see a lot of cicadas in their yards or nearby areas, and others will not.
In some places in the world, New York City, for example, there was so much development ove.