AUGUST

2008

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

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08-14-08

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Dusty Roads and Grasshoppers

Grasshoppers are one type of insect that lives up to their name. These insects jump, and they feed on plants, primarily grass. There are about 11,000 different species of grasshoppers that have been identified, and these insects can be found almost anywhere in the world.

Grasshoppers have probably caused more loss of crops and associated human famine than any other type of insect. A grasshopper, the migratory locust, has plagued humankind for thousands of years in parts of Africa and the Middle East. The destruction caused by this insect is mentioned several times in the Bible, including the swarms of locusts that became the 8th plague visited upon Egypt preceding the Exodus.

In general, problems with grasshoppers as crop pests are most severe in areas where annual rainfall averages less than 25 inches. Periods of drought, such as that the central part of the United States experienced in the 1930s, can also result in high numbers of grasshoppers and the devastating damage they can cause.

It was during those Dust Bowl years that tales of grasshopper hoards eating everything in sight became legendary. In some areas, hungry hoppers in search of a meal gnawed every plant down to ground level. Nothing was said to be immune to the feeding frenzy of grasshoppers, and even straw hats and pitchfork handles left in the path of the marauding insects suffered damage.

Not all species of grasshoppers benefit from dry conditions, but most major pest species do. So what is it about dry environments that favor grasshoppers? To begin with, warm and dry conditions allow early hatching of egg masses and early maturity of adults. That generally results in more eggs deposited in the fall because of a long egg-laying period. Moist conditions also promote development of natural fungal pathogens that kill grasshoppers. In addition, precipitation will physically kill young grasshoppers. This all adds up to higher grasshopper populations in dry climates and during drier years in wetter climates.

Grasshoppers can be a real menace to gardeners and farmers, but, like all insects, hoppers do have a good side. These insects are a food item for many animals, including birds and fish. Many ground-dwelling wild birds such as quail, pheasant and turkey catch and eat grasshoppers. So do domestic fowl such as chickens and guineas. Fish sometimes prey on grasshoppers that jump and accidentally land in water.

Years ago as a youngster in Kansas, I encountered grasshoppers frequently and found that these insects were good for several things. For instance, big yellow grasshoppers were wonderful bait when trying to catch catfish at the old fishing hole. They were also a source for amusement. I was amazed at the fact that grasshoppers produced what appeared to be tobacco juice from their mouths when captured. I discovered, by doing a taste test, that the juice that oozed from the mouth of a grasshopper was very distasteful! As it turns out, the grasshopper regurgitates the bitter, partially digested plant material to expose predators to a bad taste. Such action leaves a bitter taste in the mouth of the predator and allows the grasshopper to escape and hop yet another day.

The Carolina grasshopper is one species of grasshopper that is distributed throughout the United States. This brown-colored insect is one of North America's largest grasshoppers and is commonly found along roadsides and in sites of disturbed vegetation. When the Carolina grasshopper is at rest, its brown color blends with the soil. However, the back wings of the grasshopper are black in color with a yellow band along the back edge. These wings are in full view when the grasshopper flies. This is what some scientist call the "now you see me, now you don't" approach to protective coloration.

In Kansas, we called this insect the "dusty road grasshopper" because it often could be found sitting on dirt roads that were very dusty in the summer time. Chasing grasshoppers on a dirt road was great entertainment for young farm boys in Kansas. We didn't have computer games in those days!

 

Writer: Tom Turpin
Editor: Olivia Maddox