Skip to main content

#23: Cicadas

From <https://en.wikipedia.org/wiki/Cicada> © Bruce Marlin
Litinsects #23: Cicadas

When I was a kid, I once found this crazy looking thing attached to a tree in my yard and I kept it because I was so fascinated. It wasn’t until a decade later that I realized what that thing had actually been... the exoskeleton of a cicada.
Cicadas might be a pain because of the deafening noise they can make but they are really interesting and cool-looking insects.


  • Cicada calls are produced by TYMBALS, which are complex structures on the abdomen with membranes and thickened ribs. The membranes vibrate extremely quickly and the cicada’s body acts as a resonance chamber to amplify calls

  • The calls are so LOUD that males disable their own tympana (remember, insect ears?) so that they don’t damage them. At close enough range, they can actually damage human hearing!

  • ANNUAL CICADAS appear every year. Most species spend years underground during their nymphal stages but there is no sort of coordinated emergence

  • PERIODIC CICADAS, on the other hand, time their life cycle so that all members of a population reach adulthood at the same time. Their synchronized emergence occurs only once every 13 or 17 YEARS! This is a great strategy because (1) any predators feeding on them will become satiated before being able to make a big impact on the population size and (2) no predators can evolve to depend on cicadas as a food source because they would starve until the next emergence


Fun fact: The cycles of period cicadas are PRIME NUMBERS and there’s a pretty cool reason for that. Many predators have population cycles of a few years (meaning their population size peaks in some years but is lower in others). Low and even numbered cicada cycles would synch up with predator cycles much more often, resulting in more cicadas being eaten at every emergence. By timing their emergence as a prime number, the chances that it coincides with a predator’s peak population size OR with that of another species of periodic cicada are massively reduced. Nature is pretty smart that way!
Labels:

Comments

Post a Comment

Popular posts from this blog

#8: Butterfly Wings

Litinsects #8: Butterfly Wings Have you ever heard that you shouldn’t touch a butterfly’s wings or it will die? Well why is that...? Who remembers what I explained yesterday about Latin names? Butterflies and moths belong to the group LEPIDOPTERA, from the Greek words lepis for scale and pteron for wing. You probably guessed it already: butterfly wings are covered in SCALES! (Anyone starting to see a pattern with the names here? 😉 ) Butterfly scales are actually modified, flattened SETAE (aka hairs) that either partially or entirely cover the wings of most species. Some look like roof tiles, like on this here monarch, while some look more thread-like Scales protect and insulate the insect, but underneath the wing is actually transparent! Some species, like the GLASSWING BUTTERFLY, lack scales and have totally amazing see-through wings! Scales are responsible for the coloration of butterfly wings in one of two ways. First of all, scales contain
Post a Comment
Read more

#60: Cockroaches

Litinsects #60: Cockroaches Cockroaches belong to the order BLATTODEA, which is derived from the Greek word “blatta” meaning cockroach. Did you know that the Blattodea contains cockroaches AND termites? That’s right; termites are actually considered a specialized group of cockroaches! They used to be classified in an entirely different order of insects but recent genetic studies found a closer relation to cockroaches than previously thought. -Roaches are characterized by their broad, flat bodies. They have long antennae and generalized chewing mouthparts. In contrast to many other insects, which have 3, cockroaches have only 2 ocelli (or simple eyes) -Most people consider roaches to be disgusting, disease-spreading pests. But of 4,500 species, only 30 live in human habitats and are considered pests -The common name is derived from the Spanish word for the insect, “cucaracha” -Cockroaches can be found in a wide variety of habitats around the world. Many live in the tropics but
Post a Comment
Read more

#41: Centipedes

© Didier Descouens Litinsects #41: Centipedes Now for the centipedes! If you missed my last post on millipedes, go back and check it out... So how do they differ from millipedes? Unlike millipedes, which are mainly detritivores, centipedes are VENOMOUS and PREDATORY. Millipedes have a more cylindrical body whereas centipedes are usually flattened. Millipedes have (as the Latin name Diplopoda suggests) two leg pair per body segment but centipedes have only one pair per segment. As for the number of legs, centipedes can range from having 15 to about 170 pairs; this is generally fewer than millipedes have but it’s not always the case. Finally, millipedes tend to travel pretty slowly while centipedes are fast runners. Centipedes make up the group CHILOPODA. In Greek, “khelios” means lip and “poda” means foot. The name describes a pair of pincer-like appendages called FORCIPULES, located right behind the head, with which they inject venom to paralyze prey. So the “bite” of a centipe
Post a Comment
Read more