Fleas! What good are they? For two things, they teach us lessons about life.

When I was a kid, I loved to watch Superman. He was “able to leap tall buildings in a single bound.” Actually, if a person could jump like a flea, that would be no feat at all. A flea can jump 100 times it height, and 150 times its length. So for someone six feet tall, that would be 600 feet up and 750 feet forward! He’d win the Olympics in track events for sure!
Fleas go through the typical four stage insect development- egg, larvae, pupa, adult. Female fleas can lay close to 20 eggs at a time, a total of 500 eggs during her lifetime. She cannot lay eggs without blood. This is why fleas like to live on pets. The white eggs are tiny and slippery and thus, if your dog or cat has fleas and is in the house, you surely have plenty of fleas in your carpet. (By the way, a suggested way of getting rid of them is to put a piece of a flea collar into the vacuum cleaner bag. The collar gives off a poisonous nerve gas that will kill them in the bag instead of incubating them.)
The eggs hatch to larvae and after a week or two, spin a cocoon and inside are transformed into the little pest we see. They prosper in moist humid air and live about 500 days, but can actually live over 2000 days without food or water if kept just below freezing.
Before the 1800’s people actually trained fleas in what were called flea circuses. However we generally wish God hadn’t made fleas. Today they are not admired for their jumping ability but rather hated for their destructive power. Fleas spread disease by biting people. They don’t like our blood so will move over and try again. This way, the three millimeter long insect has killed over 50 million people through spreading bubonic plague, the famous Black Death. In Rome around 262 A.D. as many as 5,000 people a day died from the plague, and in London, from 1603 to 1665, over 150,000 lost their lives. The worse plague was in Europe from 1347 to 1350. Nearly 25 million people died from the flea spread plague, ¼ of the entire population. Fleas can also spread tapeworm and typhus to animals and people.
This tiny creation has two lessons to teach us. First, God cares about details. In observing a picture of a flea magnified 80 times, I marvel at the detail God gave it. David compared himself to a flea when running from Saul (1 Samuel 26:20). He wanted Saul to know he wasn’t worth his time and effort to kill. Of course we know that God was watching over David and protecting him through those years. He does the same for us. (1 Peter 5:7)
Second, small things can have big consequences. Fleas have killed more people than guns. David’s one evening of sin almost destroyed a nation. Solomon reminds us the little foxes can spoil the vine (SS 2:15) and a little folly can ruin a good reputation (Ecc. 10:1). Perhaps the Lord gave us the flea to teach us not to underestimate the power of little things, whether good or evil.