Updated: Apr 16
Cicadas are most well known for being loud insects found clinging to trees. They tend to be quite large and some people have a genuine fear of them. But is there anything to be afraid of? Let's delve into the curious world of the cicada to find out more.
There are many species of cicada and each has a number of amazing characteristics: from defense mechanisms to colorization, so this article will be a general overview of the family from a more broad perspective.
Cicadas have been around since before the dinosaurs. Their size has remained somewhat consistent over the last 100 million years (between 0.75 to 2.25 inches). They have large powerful wings and a broad thorax (middle section). Modern cicadas tend to have large heads with eyes placed far apart on the head. They are classified as True bugs. So, they are more closely related to aphids and water bugs than beetles, ants, or wasps. However, like ants, they have three mini-eyes (ocelli) in the center of their head. This places them apart from many other true bugs.
Urban legend has it that adults don't have mouthparts. This is not true. Like mosquitos and waterbugs, they have a rostrum that is designed to pierce flesh. In their case, the flesh of plants as they are sapsuckers. They have a symbiotic relationship with bacteria that allows them to get sufficient nutrition from their diet (much like how our gut biome provides nutrients for us). Though they are not bloodsuckers, they may try to probe you for food if one lands on you. Luckily, you are too squishy. Just gently remove the insect. Do not crush the poor creature. It's just looking for a meal or a mate.
When swarming in groups, they are known as a cloud or a plague. They are often colloquially called locusts as well. This is unfortunate, however, as cicadas do not destroy crops.
Cicadas are victims of a number of creatures such as ants, parasitic wasps, rodents, reptiles, birds, and various small mammals. As they emerge at various times it is difficult to say that there is a predator/prey relationship in the strictest sense. They are just like Manna from Heaven when they emerge as they are slow-moving and most have no major defenses. They survive through sheer numbers.
Cicadas have the longest insect life cycle. It is often stated that cicadas emerge every seven years or every 17 years. Obviously, something is wrong with this statement as we hear them every year, sometimes multiple times a year (depending on the species). What's going on? Well, in fact, different populations and species of cicada mate in different seasonal years and thus emerge at different times. The 'seven years' is often confused with the seven periodicals (the Magicicada genus). There are seven known species of cicadas that have 13 to 17-year life cycles. Populations of the same species that reside near each other and have taken to the soil at the same time, all tend to emerge together. But not all populations are periodicals. Some are annuals[sic] emerging every 2 to 10 years. Essentially, you have different species and populations emerging at different times throughout the year. So, even though one group may not emerge for 13-17 years, another populations' 13-17 years may be up. They commonly emerge in late April and early May.
After the female cicada mates, it places eggs on either a leaf or usually in the bark or flesh of a plant. The nymphs hatch and bury themselves underground. There, they feed for between 2 to 17 years from the nutrients within the roots of plants.
Fun Fact: The mating calls of the males differ between species. Some can reach loud enough sounds to damage human hearing at 100 dB. Sounds at just 70 dB for prolonged periods is considered harmful to human hearing. The most familiar cicada call in the US South is this one from the species Neotibicen superbus.
They have a worldwide distribution with annuals being more common in the US. They are not present in regions where temperatures do NOT have seasonal changes warm enough to develop their young.
Watch this video below where David Attenborough narrates the emergence of periodic cicadas.
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