Many insects reach their largest and hungriest growth stage in late summer. In our plant pests class at Trident Technical College, we study insects up close — some students can’t bring themselves to even touch them. We identity them for an insect collection. There is one insect that is easy to find this time of year.
It’s the cicada.
Cicadas have a distinctive song. It sounds like summer vacation and passes through the trees like an audible wave, starting on one side of the woods and gently moving to the other side. The male adult cicadas do all the singing during the day in hopes of finding a mate. The female responds to the male’s siren song with a wing click. Not exactly the sound of summer, but it’s enough to signal the male to come hither. The male’s song changes the closer he gets to the female until the magic is made.
You might not like the cicada song; it depends on the cicada. There are over 150 species of cicada in the United States. Seven of the species are periodical cicadas that emerge all at the same time. They’re called periodical because of the extremely long development: 13 and 17 years.
Once the singing male cicada finds the female, she lays her eggs in a woody stem. A few weeks later, the nymphs drop to the soil. The nymphs are strange grubby-looking creatures with forelegs made for digging. Now, here’s the crazy part: The juvenile nymph burrows in the ground and lives for 13 or 17 years, depending on the species. For an insect, that’s ancient. Your kid could go from diapers to driving a car by the time a 17-year cicada emerges from the ground.
When the long cycle of immaturity is over, periodical cicada nymphs surface nearly all at the same time. The synchronized emergence makes for very loud song. In some cases, it’s greater than 90 decibels — that’s like standing next to a lawn mower.
There are plenty of sources that chart the emergence of periodical cicadas and predict when and where future developments will take place. While some occur in the Upstate, none of the sources I found predicted an emergence in the Lowcountry.
However, we do have plenty of non-periodical cicadas. Annual, or dog-day, cicadas begin emerging in late spring in the Charleston area when the nymph climbs up a vertical surface, like a tree or fence post. There are creepy time-lapsed transformations on YouTube that show how the adult bursts from the nymph like an alien. Once the adults’ wings harden, they leave the nymphs’ empty exoskeletons behind like a hollowed-out shell.
The adults are big, bullet-shaped insects with green exoskeletons and clear wings. The bulbous compound eyes are about the only resemblance they have with the nymph. They don’t sting or bite. What little feeding and egg-laying they do on trees is relatively harmless. What do they do besides sing the song of summer?
They feed other organisms.
Rodents, birds, fish, fungi and other insects eat cicadas. One of the most dramatic displays of a predator-prey interaction involves the cicada killer wasp. This large, solitary wasp paralyzes a cicada with her stinger. Often times the cicada is almost too big for her to carry and you can hear the cicada let out an alarming cry. The wasp eventually flies her paralyzed victim to a burrow she previously dug in the soil where she will lay her eggs. Her larva hatch and feed on the cicada.
Nature can be cruel.
My students will find plenty of cicada exoskeletons for their collection during the fall semester and occasionally an expired adult. Every once in a while, someone finds a cicada killer wasp. With unlimited extra credit, the record-setting score keeps getting higher. Trevor Alderson had what seemed like an untouchable grade a few years ago. Addison Braswell topped his score last year.
This year’s challengers have already begun collecting.