S2E2: Insects

This week on the Petri Dish:

Science News

Remember This Fact?: What is an insect?

Science Myth: Flies fly north for the winter.

Science Controversy: Insecticide usage.

Film of the Week: Starship Troopers


Further Thoughts
In his seminal poem, If, Rudyard Kipling said, "Yours is the Earth and everything that's in it." It's a thought that's cropped up in a lot of societies (especially in religions) over history: the Earth belongs to us.

Unfortunately, in reality, the Earth does not belong to us. The world probably belongs to bacteria, but even just within the animal kingdom, we aren't the masters of the world. The world belongs to insects.

There are somewhere between 6 and 10 million species of insect on Earth, only about a million of which have been described. According to some estimates, 90% of the differing visible life forms on earth are insects.

To talk numbers, there are approximately 2,200 species of praying mantis, 5,000 dragonfly, 20,000 grasshopper, 82,000 true bug, 120,000 fly, 110,000 bees, wasp, ant and sawfly, 170,000 butterfly and moth, and 360,000 beetle species described to date (and remember there are 6 to 10 times that waiting to be described). There are so many species of beetle that, when asked if anything could be concluded about the Creator from the study of creation, J. B. S. Haldane said, "An inordinate fondness for beetles."

In contrast, there are only about 5,400 species of mammal.

Insects range in size from 0.14 mm (the fairyfly) to 57 cm long (a stick insect). The largest overall, though (as in, the heaviest and the bulkiest) are the Goliath beetles, which can be 11 cm long but weigh up to 50 g. The biggest insect in history is a species of dragonfly named Meganeura, which had a wingspan of 75 cm. They are the only class of animals (except birds and bats) that can fly, and can have more complex societies than any animal except humans.