Friday, May 15, 2015

Fun Friday Facts #106: Weird Insect Behaviors

There are about 950,000 known species of insects – compared to only about 60,000 species of vertebrates (mammals, fish, reptiles, birds, and amphibians), and about 297,000 species of plants, including lichens and red and green algae. Most scientists agree that there are more unknown (unnamed, undocumented) species of insects than there are known ones – between two and 30 million species of insects have yet to be named by scientists. At any given moment, there are ten quintillion (10,000,000,000,000,000,000) living insects on the planet.

And most of them are doing really weird things.

The pine processionary is a moth that lives in North Africa, Central Asia, and southern Europe, where it is most destructive to the pines and cedars of the region. It gets its name from the odd behavior of its caterpillars, which do this:

A single generation of these caterpillars is capable of destroying as much as 73 percent of a pine forest. Though they’re only about 20 millimeters long when they first hatch, they are capable of biting through pine needles at birth. Though the baby caterpillars stick to eating only the needles within their tent-like cocoons at first, they eventually emerge to eat the rest of the forest, forming this caterpillar train in order to bust through the cocoon walls.

Most species of ants are foragers. They pick up whatever food they can find lying around, or maybe they milk some aphids or something. The Allomerus decemarticulatus, an Amazonian species, sets traps for its prey, because of course it does. They do this by cutting plant fibers from the stem of a plant to build a raised, hollow platform that looks like a normal deformity. Holes in the platform allow the ants to hide beneath it, and when an unwary insect ventures onto the platform,  the predatory ant darts out and snatches it by the leg.

The ant then wedges itself in place beneath the platform, a maneuver that allows it to hang on to prey up to 13,000 times bigger than it, and releases a pheromone signal that calls others of its species to its aid. Other ants will appear and pin the hapless insect down by pulling its legs out from under it, while yet another ant will dismember it. Up to 40 of these ants will hide on a single leaf, creating an ambush that no other insect can hope to escape.

Similar to this, but with more dismembering.
Image by PHGCOM from Wikimedia Commons.

Shieldbacked katydids, also known as Mormon crickets, are native to the American Southwest. They occasionally experience a population explosion, leading to swarms as dense as 100 katydids per square meter. These massive swarms sweep through towns, cities, and farmlands covering up to a mile (1.6 km) a day in the search for protein. The ones in the front have to keep moving, because they’re the only ones who find anything to eat. The ones in the back become mad with hunger, if we can accuse insects of suffering from mental illness, and cannibalize the ones in the front.

And then each other, presumably.
Image from Wikimedia Commons.