What’s so special about periodical cicadas?

So. Short and easy question.

Why do people love the periodical cicadas?

Most cicadas don’t have a 17 year life cycle

The periodical cicada is one of our national treasures, simply because it’s the insect with the longest developmental cycle. Well, the longest developmental cycle under normal conditions.

The cicadas most people encounter in the US are Tibicen cicadas. These are about the size of your thumb, camouflaged, and scream from the trees in the middle of the summer. They typically develop between 4-7 years, and some may take up to a decade. It’s kind of hard to study them, so it’s really a best guess based on observations of nesting sites.

Magicicada on the other hand, takes either 13 or 17 years to develop. The reasons aren’t entirely clear, but it appears their strategy is to emerge in massive numbers to feed all the predators. The 13 or 17 year lifecycle helps with that, because the prime numbers keeps predators or parasites from synching up with their lifecycles.

This isn’t to say these cicadas are parasite-free; parasitic fungi have adapted to take advantage of them. Specialists this long-lived are uncommon, and the fungi’s spores just kind of hang out in the soil until the proper host shows up. Fungi spores can stay dormant for a long time, so it kind of makes sense.

There are some insects which can take longer than 17 years to develop. If challenged with bad conditions, Yucca moths can sleep for as long as 30 years. If a tree is cut down and made into a table, some beetles can extend their development by 50 years or more to make up for the loss of nutrition from the tree dying so suddenly.

There are some reports that queen ants or termites can live for 50 years or more. These reports are difficult to determine in the field, because queens can be replaced pretty easily by members of the colony. While it’s possible, and while these are long-lived for insects, it’s really hard to know for sure.

I apologize for the short post, but I’m being asked to move apartments due to COVID so I needed a bit of a short post. The cicadas are capturing a lot of people’s imaginations this year, though, so I wanted to give them a shout-out and mention that this is a REALLY cool thing to see. Definitely worth a road trip if you can make it!

About Polistes fuscatus

Hello, I'm the friendly admin for the Ask an Entomologist blog
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