Washington is preparing for an invasion. Several weeks from now billions and billions of insects will ascend upon the city from their hiding places under the ground to be begin two weeks or so of frenzied sex followed by egg-laying and dying. I know what your thinking – there goes Tabarrok again with his apocalyptic visions of doom and gloom.
The invaders, however, are not the biblical locusts of old but cicadas and they are going to be sex-starved because they only do this every 17 years. Why 17? No one knows for sure but 17 is prime so to meet the cicadas every time they appear a predator must lock-on to the exact frequency (while if they appeared say every 12 years then predators appearing every 2,3,4,6, or 12 years would be sure to meet them). There is another variant of periodical cicada that appears every 13 years, supporting the prime theory.
The cicadas are loud and the WashPost notes that the 1970 appearance of brood X inspired Bob Dylan to pen these lines:
And the locusts sang, well, it give me a chill,
Yeah, the locusts sang such a sweet melody.
And the locusts sang with a high whinin’ trill,
Yeah, the locusts sang and they was singing for me . . .
Addendum: Thanks to Marc Poitras for correcting me on one point. The cicadas can get plenty to eat underground so they really are coming out for the sex. Makes sense to me.