The ancient Chinese verse “dragonflies skim the water and fly gracefully” shows that people noticed the phenomenon of dragonflies skimming the water long ago. However, the ancients did not explain why dragonflies do this. It turns out that dragonflies are different from many other insects because their juvenile stage (about 1-2 years) is spent living in water. In this stage, they do not resemble the dragonflies we see, although they have three pairs of legs, they lack wings for flying. Their lower lip is very long and can extend and retract; the tip has pincers that serve as tools for catching prey. When at rest, the lower lip can fold up to cover the entire mouth. Mayfly or midge larvae in ponds are their main food. When raised artificially, they can be fed cut-up pieces of earthworms and can also eat small fish and shrimp. These dragonfly larvae are called “naiads.” The mature naiad climbs out of the water onto aquatic plants and molts to become a dragonfly. Therefore, when we sometimes see dragonflies flying low over the surface of rivers or ponds, occasionally dipping their tails into the water, it is commonly referred to as “dragonflies skimming the water.” In fact, this “skimming” is the action of laying eggs.
