Insects: Biggest! Littlest!

A Hercules beetle can be more than two inches long, and a pea aphid can fit on the head of a pin. How does it help one insect to be big and another to be little? Noted science writer Sandra Markle presents twenty-one six-legged wonders from around the world - the biggest and the littlest - and explores how their size helps them find food, avoid enemies, and fight for mates.