Grasshoppers

Grasshoppers, familiar insects of summer, are found all over the world with about 550 species native to North America.  Grasshoppers, crickets, and katydids make up the insect order Orthoptera, characterized by hard, external skeletons, three pairs of jointed legs, three-part bodies, compound eyes and two antennae.  Their mouths are used to shear vegetation and the palps on either side of the mouth are used for feeling and tasting.  Tympanal organs are holes under the wings, at the base and sides of the abdomen and perform the same function as human ears.  They have a leathery upper pair of wings that folds over to cover and protect a lower pair of wings.  The back legs are large and muscular for jumping.

Grasshoppers are one of the many insects that use singing to attract a mate.  The hind legs are used as a “bow”.  A set of peg-like protrusions on the inside of the leg are drawn across a raised vein on the forewing making a rasping sound.  This is called stridulation.  Other species may use crepitation, the ability to make loud snapping noises with their wings while in flight.  Although both males and females are capable singers, singing is all about staking territory and finding a mate, and males tend to be more vociferous.  Grasshoppers are strictly daytime singers and get more vocal as daytime temperatures soar.

In all singing insects, females will begin searching for a place to lay eggs immediately after mating.  Breeding sites require undisturbed soil found in empty lots, roadsides and open fields.  A female will push her ovipositor into the soil and secrete a frothy substance within which the eggs are suspended.  This dries into an inch long plug containing two to a hundred eggs.  Eggs remain underground over winter and hatch in spring.  Nymphs are simply miniature adults, molting through five instar stages while they grow.  Wings and sexual organs develop during this period.  A large number of eggs are lost each year to soil disturbance and weather, especially flood conditions.

Grasshoppers are a type of locust, a group of insects found in swarms that may be harmful to crop production, although this behavior is rare in Illinois.  They are well adapted to urban environments, feeding mostly on a variety of grasses, but they may also eat leafy vegetables, beans, corn and ragweed.  In agricultural fields their favorite foods include alfalfa, corn, barley, and wheat.  A heavy infestation of 16-17 grasshoppers per square yard will consume one ton of leaves per day in a 40 acre field.  Grasshoppers are particularly hard to control because of their great mobility, but, there are natural controls from predators including poultry, birds of prey, spiders and rodents to diseases caused by fungi, protozoa and nematodes.

Observe a grasshopper while it is eating and notice the ragged, serrated edge left along the chewed area versus the smooth-edge cut from a caterpillar.  When molting, they hang upside down from grass or twigs.  The skin splits open along the back and the insect pushes outward to clear its wings and antenna first from the old casing.  When moving through wet soil, hopping leaves two deep impressions from the rear legs with four much lighter impressions from the front toes and sometimes a line down the center where the abdomen may drag.  Nymphs are able to move long distances by walking, while adults can fly miles at elevations of several  hundred feet.  Have some fun watching these interesting insects and their behaviors in your own backyard.