Planthopper nymph (Nogodinidae)
Image by Trond Larsen
If you are thinking “that thing looks like fireworks are coming out of its butt” then I wholeheartedly agree with you. Reminiscent of the popular song “Firework” by Katy Perry, the “thing” is a member of the superfamily Fulgoroidea and is more commonly known as a planthopper (or specifically this one is a planthopper nymph, its juvenile stage). The “fireworks” are actually a waxy substance, produced mostly from glands on its abdominal section that nymphs and adult females of different species extrude for a number of reasons:
1) To protect their eggs
2) To act as a buffer to slow down descent when falling through air
3) To distract predators
4) To act incognito and conceal themselves
5) To acts as a rain repeller due to its hydrophobic attribute
And obviously to look snazzy. Which is somewhat contradictory to its whole survival tactic of avoiding unwanted attention by walking slowly and jumping as quickly as hallelujah to keep away from the clutches of those who want to devour them. In its mature form, they add to their incognito skills the power to look like the leaves and plants of the environment they dwell in. Many species also excrete honeydew, a mixture of partially digested phloem, which serves as a carbohydrate-rich food source for other organisms like bees, ants, cockroaches, and even geckos. Yum.
Another amazing feature of this creature is that it is the first ever animal discovered to have functional gear mechanism. One species of the planthopper, Issus coleoptratus, was studied by a pair of zoologists, Malcolm Burrows and Gregory Sutton from the University of Cambridge. They found that gears, that include 10 to 12 tapered teeth, located at the top of the insects hind legs interlock to propel it forward. The synchronization of both legs occur within 30 millionths of second and insure a smooth catapult. Coordination is key to this motion and if one leg lagged behind a fraction of a second after the other, the insect would be pushed off to the right or left, instead of straight forward.
However, these are only a temporary asset in a planthopper’s life. When nymphs reach maturation, it ceases to have this characteristic and instead it uses friction between its legs to synchronize jumps. The researchers hypothesized that because of the nymph’s consistent molting stage, breakage of one of the tooth in the gears can easily be replaced thus still retaining its full ability to travel, but it would prove unbeneficial to the adult planthopper, who would have to live with broken legs the rest of its life.
The existence of the biological form of mechanical gears is truly a great design by nature. Prior to this discovery, it was thought that humans had invented gears by Greek mechanics that lived in Alexandria around 300 B.C.E. It has been used over and over again as the basic concept for modern mechanization of cars and bicycles. But planthoppers have been in existence for millions of years before humans! It seems like Mother Nature was already one rotation ahead of us. Well done evolution, well done.