Cicadas and God

Brood X, also known as the Great Eastern Brood, of cicadas has emerged from the ground, in vast numbers, in at least the following parts of North America: Delaware, Indiana, Maryland, Pennsylvania, Virginia, the District of Columbia, and other places. See the Wikipedia article on this brood, and a fine article on CBS News. This blog post indicates that the Greek poet, Homer, mentioned them (and indicates that they are found outside of North America.)

There are several species of cicada. In fact, the Great Eastern Brood includes three species.

Cicadas and God?

I'd like to muse briefly about a couple of questions:

Why do cicadas emerge from the ground and become adults, every seventeen years? (Some types emerge every 13 years.)

Why are there so many of these insects?

Why 17 years? 

The correct answer is that we don't know. There are various speculations about the emergence cycle, but we don't. Nor, so far as I'm aware, do we know what timing mechanism triggers emergence and adulthood. I would guess that the insects could be ready for emergence and sexual maturity in a shorter time than 17 years. (Actually, one source says that parts of Brood X emerged 4 years early, in 2017.)

If small numbers of the insects emerged in, say, 15 or 19 years, it would be more difficult for them to find mates, hence there would be expected to be selection pressure on emerging with the vast majority. Some scientists believe that the long time underground means that the insects are protected from unusually cold outdoor temperatures. Perhaps.

Why so many? 

This source indicates that Brood IX, which became adults in 2020, had a population density of 1.5 million adults per acre.

Again, we don't know for sure why there are so many cicadas. Probably the large numbers mean that predators can't catch and eat them all, especially if the predators can't "count on" that same food source every year. So many of the insects escape, and are able to reproduce.

Psalm 104 says "24 Yahweh, how many are your works! In wisdom, you have made them all. The earth is full of your riches. 25 There is the sea, great and wide, in which are innumerable living things, both small and large animals." (World English Bible, public domain) The Psalmist doesn't mention cicadas, or even locusts, which occur in areas near Israel, in vast numbers. But the "full of your riches" and "innumerable living things" could refer to cicadas. Their presence, loud as they are, is one indication that God is bountiful, one of many. Like the stars above, the vast numbers of insects on the surface indicate God's majesty and power.

Cicadas are not dangerous. They do attack young twigs of certain trees -- that's where the females lay their eggs, which develop into nymphs, or larvae, which fall to the ground, where the animals spend their 17 years of larvahood. But they don't bite humans, or carry diseases.

The noise made by males, as part of courtship, is almost overpowering. There are a lot of cicadas, and each male makes a good bit of noise. Currently, it's impossible to go outside in Maryland, whre I live, without hearing that loud hum constantly. They can also be heard inside our dwelling, even with all the windows shut.

Thanks for reading.

Added, June 7, 2021: Thanks to a reader for this link, which is from The Washingtonian, and says that there are so many cicadas in the DC area that they are showing up on weather radar.