Blattodea

Order

BLATTODEA (Greek, blatta = an insect that shuns ligh)

 Description

There are thousands of species of cockroaches worldwide, but only about ten are household pests. All species have a flattened body with the head attached and constructed in such a way that the mandibles open vertically downwards. The compound eyes are generally well developed, but they may be absent in cave dwelling species. Simple eyes (ocelli) if present are represented by two pale spots. Cockroaches have filiform antennae (composed of short, straight segments) and the legs are often spiny. Body colour is generally reddish-brown, brown or black. Wings may or may not be present - many Australian native species of cockroach are wingless. When present, the forewings are often partially hardened into protective covers (tegmina) to prevent damage to the hind wings which are used for flying.

Life Cycle

There is no metamorphic cycle of egg-larva-pupa-adult in these insects. The juveniles emerge from the eggs as wingless replicas of the adults (nymphs) and grow by successive moults until they reach mature size.

Distribution

Cosmopolitan, predominantly tropical

Members

Cockroaches.

Food

Cockroaches are essentially scavengers. The "domestic" species have been known to consume white-wash, books, boots, hair, skin, finger nails, ink, their own egg cases and any material that has food value. The Australian wood cockroaches eat plant debris while other species consume wood by employing flagellate protozoans to digest the cellulose in the same manner as termites.

Importance

To human economics, harm from cockroaches is not so much created by the amount of food consumed by the insects, but rather by the spoilage created through their activities. Faeces are left on any area where they have been feeding and their habit of first softening their meal by covering it with both digestive tract enzymes and stomach contents leaves extremely unpleasant odours behind. They are also well known as disease carriers. Australian wood cockroaches appear to be important in the food chains of arachnids such as spiders. Empty husks of numbers of cockroaches are sometimes found in the web/nest areas of spiders. There are thousands of species of cockroaches worldwide, but only about ten are household pests. All species have a flattened body with the head attached and constructed in such a way that the mandibles open vertically downwards. The compound eyes are generally well developed, but they may be absent in cave dwelling species. Simple eyes (ocelli) if present are represented by two pale spots. Cockroaches have filiform antennae (composed of short, straight segments) and the legs are often spiny. Body colour is generally reddish-brown, brown or black. Wings may or may not be present - many Australian native species of cockroach are wingless. When present, the forewings are often partially hardened into protective covers (tegmina) to prevent damage to the hind wings which are used for flying. Life Cycle There is no metamorphic cycle of egg-larva-pupa-adult in these insects. The juveniles emerge from the eggs as wingless replicas of the adults (nymphs) and grow by successive moults until they reach mature size. Distribution Cosmopolitan, predominantly tropical Members Cockroaches. Food Cockroaches are essentially scavengers. The "domestic" species have been known to consume white-wash, books, boots, hair, skin, finger nails, ink, their own egg cases and any material that has food value. The Australian wood cockroaches eat plant debris while other species consume wood by employing flagellate protozoans to digest the cellulose in the same manner as termites. Importance To human economics, harm from cockroaches is not so much created by the amount of food consumed by the insects, but rather by the spoilage created through their activities. Faeces are left on any area where they have been feeding and their habit of first softening their meal by covering it with both digestive tract enzymes and stomach contents leaves extremely unpleasant odours behind. They are also well known as disease carriers. Australian wood cockroaches appear to be important in the food chains of arachnids such as spiders. Empty husks of numbers of cockroaches are sometimes found in the web/nest areas of spiders.