Column: Exactly what is a locust?

Published 6:42 am Thursday, January 11, 2007

By Staff
I must be getting more weird than I normally am. For no particular reason, over the last few weeks thoughts of locusts keep popping up in my mind. Not locust trees, but bug type locusts. I'm even dreaming about them. I have no idea why, other than maybe it bugged me (pun intended) that I knew nothing about them. I didn't even know for sure what a locust was until now. I had a hunch the term locust was just another word for a grasshopper. But, if so, why don't we have the big, crop devastating locust swarms today that we heard about in history class? Hopefully, filling this knowledge void will get the stupid thought out of my mind.
It turns out I was partially right in thinking a locust was a grasshopper. Locusts are grasshoppers but a unique kind spawned by weather. There's a family of grasshoppers called short horned grasshoppers consisting of a half dozen or so species that under certain conditions transform into one of the terrors of the world. It's when they go awry that we call them locusts. When an area inhabited by one of the locust species experiences extremely wet and hot weather the locusts go on a breeding orgy. The females dig holes in the ground where they lay egg pods containing about 100 eggs. In just two to three weeks the eggs hatch. The newly hatched nymphs look like grasshoppers but are flightless. Under ideal circumstances the success rate is great and things start to get a little crowded. Normally solitary, the overcrowded grasshoppers become gregarious and begin wandering about in packs chomping down anything that resembles food, including agricultural crops. It's when they swarm like this that they are called locusts.
As the nymphs enter the adult stage they grow wings and become more mobile. With the right weather locusts can produce four generations per year and by the time the fourth generation appears overcrowding is severe beyond belief, as in 5000 locusts per square yard! It's the stumbling, bumping and jostling of each other that sets them into motion. When their hind legs get bumped by other locusts several times a minute for a period of four hours it triggers them to swarm together en masse and hit the road. These swarms are typically several miles across and the cloud can extend up to a mile in the air. An average swarm contains about 70 million locusts per square mile. The swarm travels great distances in a rolling, leap frog-like wave consuming every edible plant in its path. They can destroy entire crop fields in just minutes. From time immemorial locust swarms have devastated entire populations with famine. The Bible refers to locusts as the Eighth Plague of the world.
The locusts that plagued North America until the twentieth century were Rocky Mountain locusts. These were the most prolific locusts on the planet, forming swarms encompassing up to 250,000 square miles, an area larger than Colorado. In 1875 at Plattsmouth, Neb. a swarm was recorded 1,800 miles long by 110 miles wide. It took five days for the seething mass to pass through the town, leaving the inhabitants literally bug nuts. For reasons not totally agreed upon the Rocky Mountain locust suddenly went extinct in the late 1800s. The most plausible theory is that when the valleys of the Rockies, which were the breeding grounds of the locust, were inundated by farms in the late 1800's the locust eggs were plowed up and destroyed to the point the population could not sustain itself.
Locusts are still a major problem in other parts of the world, especially Africa and Asia. Swarms have been recorded somewhere on earth each and every year since 1860. Locusts are controlled to a degree with pesticides but at the toll to the environment and human health that comes along with heavy pesticide use. Ironically, the Rocky Mountain locust is the only major pest species that man has ever totally eradicated and we didn't even do it on purpose. Carpe diem.