|
|
|
Order
ORTHOPTERA(Greek, orthos = straight; pteron = wing)
Common Names
grasshoppers, locusts, crickets, katydids
Description
Orthopterans have antennae which may be extremely long (extend beyond the insect�s body length) or relatively short (less than one third of the body length) but in all cases the antennae are constructed of short, straight segments (filiform). Prominent compound eyes are usually present and simple eyes (ocelli) may be present. All species have well developed mandibles which in some cases may be so large as to be capable of producing an unpleasant bite (e.g. the tree cricket, Paragryllacris combusta). The rear pair of legs are almost always modified for jumping and are frequently spiny. Numerous species use the leg spines and/or specially modified sections of the wings to produce sounds that are used in courtship; the "chirping" of crickets at dusk is commonly heard in gardens. There are two pairs of wings but the forewings are usually modified so that they become leathery wing protectors (tegmina).
Life Cycle
Females are equipped with a tube at the end of the abdomen (ovipositor) which is used to insert eggs into a suitable substrate. Many species of locust lay their eggs directly into soil but other species glue their eggs onto leaves. The young emerge from the eggs as wingless miniatures of the adults (nymphs) and mature through moults. In some cases it is difficult to distinguish between the last few stages of winged insects and sexually mature adults.
Food
Most grasshopper and katydid species eat plants, either fresh or dry. Many crickets actively hunt insects or similar prey.Importance
Grasshoppers and katydids are more of a nuisance than damaging pests in household gardens. However, locusts have always been known as major pests to farmers. Enormous quantities of eggs are laid by locust swarms and some estimates have been as much as one billion eggs per hectare. Huge locust swarms can totally destroy cereal crops and have contributed to famine in Africa and Asia. The insects are wasteful feeders as they tend to attack stems and the whole plant is then destroyed.