In celebration with the upcoming Endangered Species Day (May 17) and World Bee Day (May 20), we're re-introducing the following blog post that was originally posted by Jillian Neece on May 19, 2021.

The wait is finally over! After seventeen years, cicadas of the Northern Illinois brood (Brood XIII) will be emerging from their time underground to reproduce and complete their life cycles. The last time these bugs emerged was in 2007, and after this summer, they won’t be back again until 2041. I saw cicadas last year. What makes this year so special? Well, there are two different types of cicadas in our area: annual and periodical cicadas. Annual cicadas, also called “dog days” cicadas, emerge every year during the height of summer. These species have a life cycle that lasts between two and five years, but their development is staggered so that some individuals emerge from the ground each year to mate, while others continue maturing underground. The periodical cicadas that will emerge this spring have a much longer life cycle- one of the longest life cycles of any insect- with some species developing on a 13 year cycle and others on a 17 year cycle. Instead of staggering their development so that some bugs emerge each year, periodical cicada species all emerge together. This means that every time a periodical cicada brood emerges, we can expect hundreds of thousands of them to crawl out of their home in the soil and gather on trees and shrubs to look for a mate. We will still get the annual cicadas appearing in the late summer as they do every year, but this year we will also experience the emergence of the 17-year periodical cicadas. Why are the brood emergences so spread out? Most researchers think their life cycles are so long in order to avoid predators. When the entire species emerges at once, there are simply too many cicadas for their predators to eat. One study suggested that up to 1.5 million cicadas can emerge in a single acre! Not only will their predators have “forgotten '' that they exist since multiple generations of predators will have occurred without any cicadas emerging, the sheer number of insects overwhelms the predators and decreases the odds of any individual bug being eaten.