We have seen that insects have variously modified mouthparts according to the food they eat. However, the alimentary canal of an insect consists basically of three parts: the foregut, midgut and hindgut.
An insect like the grasshopper feeds on leaves. It uses its mouthparts to cut and crush the leaves. saliva is also poured onto the leaves from salivary glands that open into the mouth. The saliva helps to soften the leaves. The chewed food is stored in the crop and broken up further into smaller pieces in the gizzard.
At the junction of the foregut and midgut are finger like projections or caeca. These secrete enzyme rich digestive juices into the midgut. Digestion and absorption of food occurs here.
In the hindgut , absorption of water occurs. Water conservation is important in insects. Only solid faecal pellets are egested from the anus. In addition, body waste is also emptied into the hindgut through the opening of a collection of narrow tubules (malpighian tubes) found at the junction of the midgut and hindgut.
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